OSSL-GUIDE-MIGRATION(7ossl)

📦
version 15.1 · 2 versions
, in freebsd 15.1

💅 OSSL-GUIDE-MIGRATION(7ossl)

okay bestie, welcome to ossl-guide-migration (aka migration_guide) — the OpenSSL Guide: Migrating from older OpenSSL versions. this is the glow-up manual. let's get into it ✨

🌸 SYNOPSIS

See the individual manual pages for details.

🦋 DESCRIPTION

So this guide is literally the blueprint for the changes you need to make to migrate to new versions of OpenSSL. rn it covers OpenSSL 3.0 & 3.1. For anything earlier than that, bestie you gotta go look at https://github.com/openssl/openssl/blob/master/CHANGES.md instead. And if you want the tea on the key concepts that got introduced in OpenSSL 3.0, go read crypto(7). 🫶

🎀 OPENSSL 3.1

✨ Main Changes from OpenSSL 3.0

okay so THE thing here: the FIPS provider in OpenSSL 3.1 includes some non-FIPS validated algorithms 😳 which means the property query "fips=yes" is mandatory for applications that want to operate in a FIPS approved manner. no cap. the algorithms in question are:

  • Triple DES ECB
  • Triple DES CBC
  • EdDSA

and that's it — there are no other changes requiring additional migration measures since OpenSSL 3.0. iconic, honestly. 💅

👑 OPENSSL 3.0

🌈 Main Changes from OpenSSL 1.1.1

🔥 Major Release

OpenSSL 3.0 is a major release, so any application that currently uses an older version of OpenSSL will — at the very least — need to be recompiled in order to work with the new version. it's giving "new era". The intention is that the large majority of applications will work unchanged with OpenSSL 3.0 if those applications previously worked with OpenSSL 1.1.1. That said, this is not guaranteed and some changes may be required in some cases. Changes may also be required if applications need to take advantage of some of the new features available in OpenSSL 3.0, such as the availability of the FIPS module.

📜 License Change

In previous versions, OpenSSL was licensed under the dual OpenSSL and SSLeay licenses https://www.openssl.org/source/license-openssl-ssleay.txt (both licenses apply). From OpenSSL 3.0 this is replaced by the Apache License v2 https://www.openssl.org/source/apache-license-2.0.txt. glow-up on the paperwork fr fr 🎀

🧚 Providers and FIPS support

One of the key changes from OpenSSL 1.1.1 is the introduction of the Provider concept. Providers collect together and make available algorithm implementations. With OpenSSL 3.0 it is possible to specify, either programmatically or via a config file, which providers you want to use for any given application. OpenSSL 3.0 comes with 5 different providers as standard. Over time third parties may distribute additional providers that can be plugged into OpenSSL. All algorithm implementations available via providers are accessed through the "high level" APIs (for example those functions prefixed with "EVP"). They cannot be accessed using the "Low Level APIs". 💀

One of the standard providers available is the FIPS provider. This makes available FIPS validated cryptographic algorithms. The FIPS provider is disabled by default and needs to be enabled explicitly at configuration time using the "enable-fips" option. If it is enabled, the FIPS provider gets built and installed in addition to the other standard providers. No separate installation procedure is necessary. There is however a dedicated "install_fips" make target, which serves the special purpose of installing only the FIPS provider into an existing OpenSSL installation. 👑

⚠️ Not all algorithms may be available for the application at a particular moment. If the application code uses any digest or cipher algorithm via the EVP interface, the application should verify the result of the EVP_EncryptInit(3), EVP_EncryptInit_ex(3), and EVP_DigestInit(3) functions. In case when the requested algorithm is not available, these functions will fail. no silent L's, please check your return values 🙈

See also "Legacy Algorithms" for information on the legacy provider.

See also "Completing the installation of the FIPS Module" and "Using the FIPS Module in applications".

💀 Low Level APIs

OpenSSL has historically provided two sets of APIs for invoking cryptographic algorithms: the "high level" APIs (such as the "EVP" APIs) and the "low level" APIs. The high level APIs are typically designed to work across all algorithm types. The "low level" APIs are targeted at a specific algorithm implementation. For example, the EVP APIs provide the functions EVP_EncryptInit_ex(3), EVP_EncryptUpdate(3) and EVP_EncryptFinal(3) to perform symmetric encryption. Those functions can be used with the algorithms AES, CHACHA, 3DES etc. On the other hand, to do AES encryption using the low level APIs you would have to call AES specific functions such as AES_set_encrypt_key(3), AES_encrypt(3), and so on. The functions for 3DES are different. 💀

Use of the low level APIs has been informally discouraged by the OpenSSL development team for a long time. However in OpenSSL 3.0 this is made more formal. All such low level APIs have been deprecated. You may still use them in your applications, but you may start to see deprecation warnings during compilation (dependent on compiler support for this). Deprecated APIs may be removed from future versions of OpenSSL so you are strongly encouraged to update your code to use the high level APIs instead. bestie please migrate, i'm begging 🥺

This is described in more detail in "Deprecation of Low Level Functions".

🌸 Legacy Algorithms

Some cryptographic algorithms such as MD2 and DES that were available via the EVP APIs are now considered legacy and their use is strongly discouraged. These legacy EVP algorithms are still available in OpenSSL 3.0 but not by default. If you want to use them then you must load the legacy provider. This can be as simple as a config file change, or can be done programmatically. See OSSL_PROVIDER-legacy(7) for a complete list of algorithms. Applications using the EVP APIs to access these algorithms should instead use more modern algorithms. If that is not possible then these applications should ensure that the legacy provider has been loaded. This can be achieved either programmatically or via configuration. See crypto(7) man page for more information about providers. 🦋

🫶 Engines and "METHOD" APIs

The refactoring to support Providers conflicts internally with the APIs used to support engines, including the ENGINE API and any function that creates or modifies custom "METHODS" (for example EVP_MD_meth_new(3), EVP_CIPHER_meth_new(3), EVP_PKEY_meth_new(3), RSA_meth_new(3), EC_KEY_METHOD_new(3), etc.). These functions are being deprecated in OpenSSL 3.0, and users of these APIs should know that their use can likely bypass provider selection and configuration, with unintended consequences. This is particularly relevant for applications written to use the OpenSSL 3.0 FIPS module, as detailed below. Authors and maintainers of external engines are strongly encouraged to refactor their code, transforming engines into providers using the new Provider API and avoiding deprecated methods. it's giving "your fave is problematic" 😭

🔧 Support of legacy engines

If openssl is not built without engine support or deprecated API support, engines will still work. However, their applicability will be limited.

New algorithms provided via engines will still work.

Engine-backed keys can be loaded via custom OSSL_STORE implementation. In this case the EVP_PKEY objects created via ENGINE_load_private_key(3) will be considered legacy and will continue to work.

To ensure the future compatibility, the engines should be turned to providers. To prefer the provider-based hardware offload, you can specify the default properties to prefer your provider.

Setting engine-based or application-based default low-level crypto method such as RSA_METHOD or EC_KEY_METHOD is still possible and keys inside the default provider will use the engine-based implementation for the crypto operations. However EVP_PKEYs created by decoding by using OSSL_DECODER, PEM_ or d2i_ APIs will be provider-based. To create a fully legacy EVP_PKEYs EVP_PKEY_set1_RSA(3), EVP_PKEY_set1_EC_KEY(3) or similar functions must be used. ⭐

🌟 Versioning Scheme

The OpenSSL versioning scheme has changed with the OpenSSL 3.0 release. The new versioning scheme has this format:

MAJOR.MINOR.PATCH

For OpenSSL 1.1.1 and below, different patch levels were indicated by a letter at the end of the release version number. This will no longer be used and instead the patch level is indicated by the final number in the version. A change in the second (MINOR) number indicates that new features may have been added. OpenSSL versions with the same major number are API and ABI compatible. If the major number changes then API and ABI compatibility is not guaranteed. 🎀

For more information, see OpenSSL_version(3).

🚀 Other major new features

Certificate Management Protocol (CMP, RFC 9810)

This also covers CRMF (RFC 4211) and HTTP transfer (RFC 9811). See openssl-cmp(1) and OSSL_CMP_exec_certreq(3) as starting points.

HTTP(S) client

A proper HTTP(S) client that supports GET and POST, redirection, plain and ASN.1-encoded contents, proxies, and timeouts. 🤩

Key Derivation Function API (EVP_KDF)

This simplifies the process of adding new KDF and PRF implementations.

Previously KDF algorithms had been shoe-horned into using the EVP_PKEY object which was not a logical mapping. Existing applications that use KDF algorithms using EVP_PKEY (scrypt, TLS1 PRF and HKDF) may be slower as they use an EVP_KDF bridge internally. All new applications should use the new EVP_KDF(3) interface. See also "Key Derivation Function (KDF)" in OSSL_PROVIDER-default(7) and "Key Derivation Function (KDF)" in OSSL_PROVIDER-FIPS(7).

Message Authentication Code API (EVP_MAC)

This simplifies the process of adding MAC implementations.

This includes a generic EVP_PKEY to EVP_MAC bridge, to facilitate the continued use of MACs through raw private keys in functionality such as EVP_DigestSign(3) and EVP_DigestVerify(3).

All new applications should use the new EVP_MAC(3) interface. See also "Message Authentication Code (MAC)" in OSSL_PROVIDER-default(7) and "Message Authentication Code (MAC)" in OSSL_PROVIDER-FIPS(7).

Algorithm Fetching

Using calls to convenience functions such as EVP_sha256() and EVP_aes_256_gcm() may incur a performance penalty when using providers. Retrieving algorithms from providers involves searching for an algorithm by name. This is much slower than directly accessing a method table. It is recommended to prefetch algorithms if an algorithm is used many times. See "Performance" in crypto(7), "Explicit fetching" in crypto(7) and "Implicit fetching" in crypto(7). ⚡

Support for Linux Kernel TLS

In order to use KTLS, support for it must be compiled in using the "enable-ktls" configuration option. It must also be enabled at run time using the SSL_OP_ENABLE_KTLS option.

New Algorithms

  • KDF algorithms "SINGLE STEP" and "SSH"

See EVP_KDF-SS(7) and EVP_KDF-SSHKDF(7)

  • MAC Algorithms "GMAC" and "KMAC"

See EVP_MAC-GMAC(7) and EVP_MAC-KMAC(7).

  • KEM Algorithm "RSASVE"
  • See EVP_KEM-RSA(7) for the whole story, bestie. 💅
  • Cipher Algorithm "AES-SIV" — peep the "SIV Mode" section in EVP_EncryptInit(3). ✨
  • AES Key Wrap inverse ciphers supported by the EVP layer — okay so these inverse ciphers use AES decryption for wrapping and AES encryption for unwrapping. The algorithms are "AES-128-WRAP-INV", "AES-192-WRAP-INV", "AES-256-WRAP-INV", "AES-128-WRAP-PAD-INV", "AES-192-WRAP-PAD-INV" and "AES-256-WRAP-PAD-INV". 🔥
  • CTS ciphers added to the EVP layer — the algorithms are "AES-128-CBC-CTS", "AES-192-CBC-CTS", "AES-256-CBC-CTS", "CAMELLIA-128-CBC-CTS", "CAMELLIA-192-CBC-CTS" and "CAMELLIA-256-CBC-CTS". The CS1, CS2 and CS3 variants are supported. 🎀

CMS and PKCS#7 updates 💌

  • Added CAdES-BES signature verification support. ✅
  • Added CAdES-BES signature scheme and attributes support (RFC 5126) to the CMS API. 🦋
  • Added AuthEnvelopedData content type structure (RFC 5083) using AES_GCM.

This uses the AES-GCM parameter (RFC 5084) for the Cryptographic Message Syntax. Its whole purpose is to support encryption and decryption of a digital envelope that is both authenticated and encrypted using AES GCM mode. 🔐

PKCS#12 API updates 🌸

The default algorithms for pkcs12 creation with the PKCS12_create() function were changed to more modern PBKDF2 and AES based algorithms. The default MAC iteration count was changed to PKCS12_DEFAULT_ITER to make it equal with the password-based encryption iteration count. The default digest algorithm for the MAC computation was changed to SHA-256. The pkcs12 application now supports the -legacy option that restores the previous default algorithms to support interoperability with legacy systems. 🫶

Added enhanced PKCS#12 APIs which accept a library context OSSL_LIB_CTX and (where relevant) a property query. Other APIs which handle PKCS#7 and PKCS#8 objects have also been enhanced where required. This includes:

PKCS12_add_key_ex(3), PKCS12_add_safe_ex(3), PKCS12_add_safes_ex(3), PKCS12_create_ex(3), PKCS12_decrypt_skey_ex(3), PKCS12_init_ex(3), PKCS12_item_decrypt_d2i_ex(3), PKCS12_item_i2d_encrypt_ex(3), PKCS12_key_gen_asc_ex(3), PKCS12_key_gen_uni_ex(3), PKCS12_key_gen_utf8_ex(3), PKCS12_pack_p7encdata_ex(3), PKCS12_pbe_crypt_ex(3), PKCS12_PBE_keyivgen_ex(3), PKCS12_SAFEBAG_create_pkcs8_encrypt_ex(3), PKCS5_pbe2_set_iv_ex(3), PKCS5_pbe_set0_algor_ex(3), PKCS5_pbe_set_ex(3), PKCS5_pbkdf2_set_ex(3), PKCS5_v2_PBE_keyivgen_ex(3), PKCS5_v2_scrypt_keyivgen_ex(3), PKCS8_decrypt_ex(3), PKCS8_encrypt_ex(3), PKCS8_set0_pbe_ex(3).

As part of this change the EVP_PBE_xxx APIs can also accept a library context and property query and will call an extended version of the key/IV derivation function which supports these parameters. This includes EVP_PBE_CipherInit_ex(3), EVP_PBE_find_ex(3) and EVP_PBE_scrypt_ex(3). 💅

PKCS#12 KDF versus FIPS — ngl, this one matters. Unlike in 1.x.y, the PKCS12KDF algorithm used when a PKCS#12 structure is created with a MAC that does not work with the FIPS provider, because the PKCS12KDF is not a FIPS approvable mechanism. 😭

See EVP_KDF-PKCS12KDF(7), PKCS12_create(3), openssl-pkcs12(1), OSSL_PROVIDER-FIPS(7).

Windows thread synchronization changes 🪟

Windows thread synchronization uses read/write primitives (SRWLock) when supported by the OS, otherwise CriticalSection continues to be used. ✨

Trace API 🧚

A new generic trace API has been added which provides support for enabling instrumentation through trace output. This feature is mainly intended as an aid for developers and is disabled by default. To utilize it, OpenSSL needs to be configured with the "enable-trace" option. 👑

If the tracing API is enabled, the application can activate trace output by registering BIOs as trace channels for a number of tracing and debugging categories. See OSSL_trace_enabled(3). 🦋

Key validation updates 🔑

EVP_PKEY_public_check(3) and EVP_PKEY_param_check(3) now work for more key types. This includes RSA, DSA, ED25519, X25519, ED448 and X448. Previously (in 1.1.1) they would return -2. For key types that do not have parameters EVP_PKEY_param_check(3) will always return 1. 💖

Other notable deprecations and changes 💀

The function code part of an OpenSSL error code is no longer relevant — this code is now always set to zero. Related functions are deprecated. 🙈

STACK and HASH macros have been cleaned up — the type-safe wrappers are declared everywhere and implemented once. See DEFINE_STACK_OF(3) and DEFINE_LHASH_OF_EX(3). ✨

The RAND_DRBG subsystem has been removed — the new EVP_RAND(3) is a partial replacement: the DRBG callback framework is absent. The RAND_DRBG API did not fit well into the new provider concept as implemented by EVP_RAND and EVP_RAND_CTX. 😭

Removed FIPS_mode() and FIPS_mode_set() — these functions are legacy APIs that are not applicable to the new provider model. Applications should instead use EVP_default_properties_is_fips_enabled(3) and EVP_default_properties_enable_fips(3). 💅

Key generation is slower — the Miller-Rabin test now uses 64 rounds, which is used for all prime generation, including RSA key generation. This affects the time for larger keys sizes. 😮‍💨

The default key generation method for the regular 2-prime RSA keys was changed to the FIPS186-4 B.3.6 method (Generation of Probable Primes with Conditions Based on Auxiliary Probable Primes). This method is slower than the original method. 🐌

Change PBKDF2 to conform to SP800-132 instead of the older PKCS5 RFC2898 — this checks that the salt length is at least 128 bits, the derived key length is at least 112 bits, and that the iteration count is at least 1000. For backwards compatibility these checks are disabled by default in the default provider, but are enabled by default in the FIPS provider. 🔥

To enable or disable the checks see OSSL_KDF_PARAM_PKCS5 in EVP_KDF-PBKDF2(7). The parameter can be set using EVP_KDF_derive(3). 🎀

Enforce a minimum DH modulus size of 512 bits — smaller sizes now result in an error. 🚨

SM2 key changes — EC EVP_PKEYs with the SM2 curve have been reworked to automatically become EVP_PKEY_SM2 rather than EVP_PKEY_EC. 🌀

Unlike in previous OpenSSL versions, this means that applications cannot call EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2) to get SM2 computations. 😬

Parameter and key generation is also reworked to make it possible to generate EVP_PKEY_SM2 parameters and keys. Applications must now generate SM2 keys directly and must not create an EVP_PKEY_EC key first. It is no longer possible to import an SM2 key with domain parameters other than the SM2 elliptic curve ones. 💜

Validation of SM2 keys has been separated from the validation of regular EC keys, allowing to improve the SM2 validation process to reject loaded private keys that are not conforming to the SM2 ISO standard. In particular, a private scalar k outside the range 1 <= k < n-1 is now correctly rejected. 👑

EVP_PKEY_set_alias_type() method has been removed — this function made a EVP_PKEY object mutable after it had been set up. In OpenSSL 3.0 it was decided that a provided key should not be able to change its type, so this function has been removed. 💀

Functions that return an internal key should be treated as read only — functions such as EVP_PKEY_get0_RSA(3) behave slightly differently in OpenSSL 3.0. Previously they returned a pointer to the low-level key used internally by libcrypto. From OpenSSL 3.0 this key may now be held in a provider. Calling these functions will only return a handle on the internal key where the EVP_PKEY was constructed using this key in the first place, for example using a function or macro such as EVP_PKEY_assign_RSA(3), EVP_PKEY_set1_RSA(3), etc. Where the EVP_PKEY holds a provider managed key, then these functions now return a cached copy of the key. Changes to the internal provider key that take place after the first time the cached key is accessed will not be reflected back in the cached copy. Similarly any changes made to the cached copy by application code will not be reflected back in the internal provider key. 😵‍💫

For the above reasons the keys returned from these functions should typically be treated as read-only. To emphasise this the value returned from EVP_PKEY_get0_RSA(3), EVP_PKEY_get0_DSA(3), EVP_PKEY_get0_EC_KEY(3) and EVP_PKEY_get0_DH(3) have been made const. This may break some existing code. Applications broken by this change should be modified. The preferred solution is to refactor the code to avoid the use of these deprecated functions. Failing this the code should be modified to use a const pointer instead. The EVP_PKEY_get1_RSA(3), EVP_PKEY_get1_DSA(3), EVP_PKEY_get1_EC_KEY(3) and EVP_PKEY_get1_DH(3) functions continue to return a non-const pointer to enable them to be "freed". However they should also be treated as read-only. 🫶

The public key check has moved from EVP_PKEY_derive() to EVP_PKEY_derive_set_peer() — this may mean result in an error in EVP_PKEY_derive_set_peer(3) rather than during EVP_PKEY_derive(3). To disable this check use EVP_PKEY_derive_set_peer_ex(dh, peer, 0). 🚨

The print format has cosmetic changes for some functions — the output from numerous "printing" functions such as X509_signature_print(3), X509_print_ex(3), X509_CRL_print_ex(3), and other similar functions has been amended such that there may be cosmetic differences between the output observed in 1.1.1 and 3.0. This also applies to the -text output from the openssl x509 and openssl crl applications. 🎀

Interactive mode from the openssl program has been removed — from now on, running it without arguments is equivalent to openssl help. 👋

The error return values from some control calls (ctrl) have changed — one significant change is that controls which used to return -2 for invalid inputs, now return -1 indicating a generic error condition instead. 💅

DH and DHX key types have different settable parameters — previously (in 1.1.1) these conflicting parameters were allowed, but will now result in errors. See EVP_PKEY-DH(7) for further details. This affects the behaviour of openssl-genpkey(1) for DH parameter generation. 🌀

EVP_CIPHER_CTX_set_flags() ordering change — if using a cipher from a provider the EVP_CIPH_FLAG_LENGTH_BITS flag can only be set after the cipher has been assigned to the cipher context. See "FLAGS" in EVP_EncryptInit(3) for more information. ⭐

Validation of operation context parameters — due to move of the implementation of cryptographic operations to the providers, validation of various operation parameters can be postponed until the actual operation is executed where previously it happened immediately when an operation parameter was set. 🦋

For example, when you set an unsupported curve with EVP_PKEY_CTX_set_ec_paramgen_curve_nid(), the function call itself won’t fail — but later keygen operations with the EVP_PKEY_CTX will fail. 😭 It’s giving “delayed rejection,” bestie.

💀 Removal of function code from the error codes 💀

The function code part of the error code is now always set to 0. For that reason the ERR_GET_FUNC() macro was removed. Applications must resolve the error codes only using the library number and the reason code. No cap, that’s the whole vibe now.

🧊 ChaCha20-Poly1305 cipher does not allow a truncated IV length to be used 🧊

In OpenSSL 3.0, setting the IV length to any value other than 12 will result in an error. Prior to OpenSSL 3.0, the ivlen could be smaller than the required 12 byte length, using EVP_CIPHER_CTX_ctrl(ctx, EVP_CRTL_AEAD_SET_IVLEN, ivlen, NULL). This resulted in an IV that had leading zero padding. So yeah, that little shortcut is not it anymore. 💅

🛠️ Installation and Compilation 🛠️

Please refer to the INSTALL.md file in the top of the distribution for instructions on how to build and install OpenSSL 3.0. Please also refer to the various platform specific NOTES files for your specific platform. Like, actually read them — they’re the group chat receipts for your platform. 🫶

🚀 Upgrading from OpenSSL 1.1.1 🚀

Upgrading to OpenSSL 3.0 from OpenSSL 1.1.1 should be relatively straightforward in most cases. The most likely area where you will encounter problems is if you have used low level APIs in your code (as discussed above). In that case you are likely to start seeing deprecation warnings when compiling your application. If this happens you have 3 options:

  1. Ignore the warnings. They are just warnings. The deprecated functions are still present and you may still use them. However be aware that they may be removed from a future version of OpenSSL. It’s giving “living on borrowed time,” but it is allowed. 🙈
  2. Suppress the warnings. Refer to your compiler documentation on how to do this.
  3. Remove your usage of the low level APIs. In this case you will need to rewrite your code to use the high level APIs instead.

🌸 Error code changes 🌸

As OpenSSL 3.0 provides a brand new Encoder/Decoder mechanism for working with widely used file formats, application code that checks for particular error reason codes on key loading failures might need an update.

Password-protected keys may deserve special attention. If only some errors are treated as an indicator that the user should be asked about the password again, it’s worth testing these scenarios and processing the newly relevant codes. Bestie, test the password loop. Do not let it get weird. 😭

There may be more cases to treat specially, depending on the calling application code.

💥 Upgrading from OpenSSL 1.0.2 💥

Upgrading to OpenSSL 3.0 from OpenSSL 1.0.2 is likely to be significantly more difficult. In addition to the issues discussed above in the section about “Upgrading from OpenSSL 1.1.1”, the main things to be aware of are:

  1. The build and installation procedure has changed significantly.

Check the file INSTALL.md in the top of the installation for instructions on how to build and install OpenSSL for your platform. Also read the various NOTES files in the same directory, as applicable for your platform.

  1. Many structures have been made opaque in OpenSSL 3.0.

The structure definitions have been removed from the public header files and moved to internal header files. In practice this means that you can no longer stack allocate some structures. Instead they must be heap allocated through some function call (typically those function names have a _new suffix to them). Additionally you must use “setter” or “getter” functions to access the fields within those structures.

For example code that previously looked like this:

EVP_MD_CTX md_ctx;

/* This line will now generate compiler errors */
EVP_MD_CTX_init(&md_ctx);

The code needs to be amended to look like this:

EVP_MD_CTX *md_ctx;

md_ctx = EVP_MD_CTX_new();
...
...
EVP_MD_CTX_free(md_ctx);
  1. Support for TLSv1.3 has been added.

This has a number of implications for SSL/TLS applications. See the TLS1.3 page https://github.com/openssl/openssl/wiki/TLS1.3 for further details.

More details about the breaking changes between OpenSSL versions 1.0.2 and 1.1.0 can be found on the OpenSSL 1.1.0 Changes page https://github.com/openssl/openssl/wiki/OpenSSL_1.1.0_Changes.

🧚 Upgrading from the OpenSSL 2.0 FIPS Object Module 🧚

The OpenSSL 2.0 FIPS Object Module was a separate download that had to be built separately and then integrated into your main OpenSSL 1.0.2 build. In OpenSSL 3.0 the FIPS support is fully integrated into the mainline version of OpenSSL and is no longer a separate download. For further information see “Completing the installation of the FIPS Module”.

The function calls FIPS_mode() and FIPS_mode_set() have been removed from OpenSSL 3.0. You should rewrite your application to not use them. See fips_module(7) and OSSL_PROVIDER-FIPS(7) for details.

🎀 Completing the installation of the FIPS Module 🎀

The FIPS Module will be built and installed automatically if FIPS support has been configured. The current documentation can be found in the README-FIPS file: https://github.com/openssl/openssl/blob/master/README-FIPS.md.

👑 Programming 👑

Applications written to work with OpenSSL 1.1.1 will mostly just work with OpenSSL 3.0. However changes will be required if you want to take advantage of some of the new features that OpenSSL 3.0 makes available. In order to do that you need to understand some new concepts introduced in OpenSSL 3.0. Read “Library contexts” in crypto(7) for further information.

🦋 Library Context 🦋

A library context allows different components of a complex application to each use a different library context and have different providers loaded with different configuration settings. See “Library contexts” in crypto(7) for further info.

If the user creates an OSSL_LIB_CTX via OSSL_LIB_CTX_new(3) then many functions may need to be changed to pass additional parameters to handle the library context.

🌈 Using a Library Context - Old functions that should be changed 🌈

If a library context is needed then all EVP_* digest functions that return a const EVP_MD * such as EVP_sha256() should be replaced with a call to EVP_MD_fetch(3). See “ALGORITHM FETCHING” in crypto(7).

If a library context is needed then all EVP_* cipher functions that return a const EVP_CIPHER * such as EVP_aes_128_cbc() should be replaced with a call to EVP_CIPHER_fetch(3). See “ALGORITHM FETCHING” in crypto(7).

Some functions can be passed an object that has already been set up with a library context such as d2i_X509(3), d2i_X509_CRL(3), d2i_X509_REQ(3) and d2i_X509_PUBKEY(3). If NULL is passed instead then the created object will be set up with the default library context. Use X509_new_ex(3), X509_CRL_new_ex(3), X509_REQ_new_ex(3) and X509_PUBKEY_new_ex(3) if a library context is required.

All functions listed below with a NAME have a replacement function NAME_ex that takes OSSL_LIB_CTX as an additional argument. Functions that have other mappings are listed along with the respective name. Bestie, this is the glow-up list. ✨

⭐ New functions that use a Library context ⭐

The following functions can be passed a library context if required. Passing NULL will use the default library context.

🌸 Providers 🌸

Okay so providers get their whole own ✨moment✨ — the tea is in "Providers" in crypto(7). Also peek at "OPENSSL PROVIDERS" in crypto(7) if you want the full roster, bestie. 👑

💅 Fetching algorithms and property queries 💅

The whole Implicit vs Explicit Fetching situation is broken down for you in "ALGORITHM FETCHING" in crypto(7). Go read it, it's giving essential lore. 📖

🎀 Mapping EVP controls and flags to provider OSSL_PARAM(3) parameters 🎀

Real talk: all those classic control functions (like EVP_CIPHER_CTX_ctrl(3)) and flag-pokers (like EVP_MD_CTX_set_flags(3)) are secretly, internally using OSSL_PARAMS to shuttle info to and from provider objects. Like, under the hood it's all params, always has been. 💫 Head to OSSL_PARAM(3) for the extra deets on parameters.

😭 Deprecation of Low Level Functions 😭

So. OpenSSL 3.0 deprecated a significant number of APIs. Like, a lot a lot. This section walks you through the common categories of the deprecation era. If you want the actual receipts — the full list of deprecated functions mapped to their categories — jump to "Deprecated function mappings". 🗺️

🧚 Providers are a replacement for engines and low-level method overrides 🧚

Any accessor that touches an ENGINE is deprecated now — yes, even EVP_PKEY_set1_engine(). If your app is out here using engines, the glow-up is providers. Periodt. ✨

And back in the day, before providers existed, algorithms got overridden by swapping out the methods the algorithm used. All those methods — RSA_new_method(), RSA_meth_new(), the whole crew — deprecated. Providers are the replacement. Slay. 💅

🔥 Deprecated i2d and d2i functions for low-level key types 🔥

Any i2d / d2i function that takes a low-level key type, like d2i_DHparams(), has been deprecated. Instead, use the OSSL_DECODER(3) and OSSL_ENCODER(3) APIs to read and write files. It's giving modern. For more, see "Migration" in d2i_RSAPrivateKey(3).

🦋 Deprecated low-level key object getters and setters 🦋

If your app sets or gets low-level key objects (think EVP_PKEY_set1_DH() or EVP_PKEY_get0()), swap to the OSSL_ENCODER (see OSSL_ENCODER_to_bio(3)) or OSSL_DECODER (see OSSL_DECODER_from_bio(3)) APIs — or honestly just use EVP_PKEY_fromdata(3) or EVP_PKEY_todata(3). Pick your fighter. 🥊

🌈 Deprecated low-level key parameter getters 🌈

Functions that reach directly into low-level objects, like RSA_get0_n(3), are deprecated now, bestie. Instead use one of:

EVP_PKEY_get_bn_param(3), EVP_PKEY_get_int_param(3), EVP_PKEY_get_size_t_param(3), EVP_PKEY_get_utf8_string_param(3), EVP_PKEY_get_octet_string_param(3), or EVP_PKEY_get_params(3)

— all of those get you fields out of an EVP_PKEY. And where's the list of gettable parameters, you ask? So glad you asked:

Apps can also flex EVP_PKEY_todata(3) to return all the fields at once. Iconic behaviour. 👑

💜 Deprecated low-level key parameter setters 💜

Same deal for the setters — functions like RSA_set0_crt_params(3) that poke low-level objects directly? Deprecated. Use EVP_PKEY_fromdata(3) to create new keys from user-provided key data. 🔑

Heads up: keys should be immutable once they're created. So if you genuinely need a modified key, the move is EVP_PKEY_todata(3), OSSL_PARAM_merge(3), and EVP_PKEY_fromdata(3). See "Examples" in EVP_PKEY-DH(7) for more. And for generating a key from parameters, see "Deprecated low-level key generation functions".

🍓 Deprecated low-level object creation 🍓

Low-level objects used to get created with methods like RSA_new(3), RSA_up_ref(3) and RSA_free(3). Nope — use the high-level EVP_PKEY APIs instead, e.g. EVP_PKEY_new(3), EVP_PKEY_up_ref(3) and EVP_PKEY_free(3). Also see EVP_PKEY_CTX_new_from_name(3) and EVP_PKEY_CTX_new_from_pkey(3). 🌟

And like, EVP_PKEYs can be created a whole bunch of ways, so also check "Deprecated low-level key generation functions", "Deprecated low-level key reading and writing functions" and "Deprecated low-level key parameter setters". So many doors, so few wrong turns. 🚪

💀 Deprecated low-level encryption functions 💀

Low-level encryption functions like AES_encrypt(3) and AES_decrypt(3) have been informally discouraged for a long-ass time. Instead, use the high-level EVP APIs: EVP_EncryptInit_ex(3), EVP_EncryptUpdate(3), and EVP_EncryptFinal_ex(3) — or EVP_DecryptInit_ex(3), EVP_DecryptUpdate(3) and EVP_DecryptFinal_ex(3). Do it for her. 🙏

🌸 Deprecated low-level digest functions 🌸

Low-level digest functions like SHA1_Init(3)? Also informally discouraged for ages, ngl. Use the high-level EVP APIs EVP_DigestInit_ex(3), EVP_DigestUpdate(3) and EVP_DigestFinal_ex(3) — or the quick one-shot EVP_Q_digest(3). One shot, no notes. ⚡

Fun fact: SHA1(3), SHA224(3), SHA256(3), SHA384(3) and SHA512(3) have changed into macros that use EVP_Q_digest(3). They said glow-up. 💫

🎀 Deprecated low-level signing functions 🎀

Low-level signing functions like DSA_sign(3) have been informally discouraged for a long time too. Instead, use EVP_DigestSign(3) and EVP_DigestVerify(3). Also see EVP_SIGNATURE-RSA(7), EVP_SIGNATURE-DSA(7), EVP_SIGNATURE-ECDSA(7) and EVP_SIGNATURE-ED25519(7). Sign it, verify it, slay it. ✍️

🦋 Deprecated low-level MAC functions 🦋

Low-level MAC functions like CMAC_Init(3) are deprecated, periodt. Use the new EVP_MAC(3) interface — EVP_MAC_CTX_new(3), EVP_MAC_CTX_free(3), EVP_MAC_init(3), EVP_MAC_update(3) and EVP_MAC_final(3) — or the single-shot MAC function EVP_Q_mac(3). Extra reading if you're obsessed: EVP_MAC(3), EVP_MAC-HMAC(7), EVP_MAC-CMAC(7), EVP_MAC-GMAC(7), EVP_MAC-KMAC(7), EVP_MAC-BLAKE2(7), EVP_MAC-Poly1305(7) and EVP_MAC-Siphash(7). 📚

Note that the one-shot method HMAC() is still available for compatibility purposes — but this can also be replaced by using EVP_Q_MAC if a library context is required.

✨ Deprecated low-level validation functions ✨

Low-level validation functions like DH_check(3) have been informally discouraged for a long time, bestie. Use the high-level EVP_PKEY APIs instead:

EVP_PKEY_check(3), EVP_PKEY_param_check(3), EVP_PKEY_param_check_quick(3), EVP_PKEY_public_check(3), EVP_PKEY_public_check_quick(3), EVP_PKEY_private_check(3), and EVP_PKEY_pairwise_check(3)

Validation but make it main character. ✅

🧚 Deprecated low-level key exchange functions 🧚

Many low-level functions have been informally discouraged for a long time. Instead, use EVP_PKEY_derive(3). See also EVP_KEYEXCH-DH(7), EVP_KEYEXCH-ECDH(7) and EVP_KEYEXCH-X25519(7). Derive, don't strive. 🤝

🔥 Deprecated low-level key generation functions 🔥

So many low-level functions, informally discouraged, you know the drill by now. Use EVP_PKEY_keygen_init(3) and EVP_PKEY_generate(3) as described in EVP_PKEY-DSA(7), EVP_PKEY-DH(7), EVP_PKEY-RSA(7), EVP_PKEY-EC(7) and EVP_PKEY-X25519(7). You can also use the 'quick' one-shot function EVP_PKEY_Q_keygen(3) plus the macros for the most common cases: <EVP_RSA_gen(3)> and EVP_EC_gen(3). Quick and cute. ⚡

🌈 Deprecated low-level key reading and writing functions 🌈

Using low-level objects (like DSA) has been informally discouraged for a long time. The functions that read and write those low-level objects (like PEM_read_DSA_PUBKEY()) should be replaced — use OSSL_ENCODER_to_bio(3) and OSSL_DECODER_from_bio(3) instead. 🫶

💜 Deprecated low-level key printing functions 💜

Again: low-level objects (hi, DSA) — informally discouraged, long time, you know how it is. Printing functions like DSA_print() should be swapped for the equivalent EVP_PKEY functions. Apps should use one of:

EVP_PKEY_print_public(3), EVP_PKEY_print_private(3), EVP_PKEY_print_params(3), EVP_PKEY_print_public_fp(3), EVP_PKEY_print_private_fp(3) or EVP_PKEY_print_params_fp(3)

FYI, internally those all use OSSL_ENCODER_to_bio(3) and OSSL_DECODER_from_bio(3). It's turtles all the way down. 🐢

🗺️ Deprecated function mappings 🗺️

These are the functions that got deprecated in 3.0, mapped out for you. Buckle up. 🎢

  • AES_bi_ige_encrypt() and AES_ige_encrypt()

There is no replacement for the IGE functions. New code should not use these modes, full stop. These undocumented functions were never integrated into the EVP layer. They implemented the AES Infinite Garble Extension (IGE) mode and AES Bi-directional IGE mode. These modes were never formally standardised, and usage of these functions is believed to be very small. In particular AES_bi_ige_encrypt() has a known bug — it accepts 2 AES keys, but only one is ever used. 😭 The security implications are believed to be minimal, but this issue was never fixed for backwards compatibility reasons.

  • AES_encrypt(), AES_decrypt(), AES_set_encrypt_key(), AES_set_decrypt_key(), AES_cbc_encrypt(), AES_cfb128_encrypt(), AES_cfb1_encrypt(), AES_cfb8_encrypt(), AES_ecb_encrypt(), AES_ofb128_encrypt()
  • AES_unwrap_key(), AES_wrap_key()

See "Deprecated low-level encryption functions".

  • AES_options()

There is no replacement. It returned a string indicating if the AES code was unrolled. That's it, that was the whole job. 💀

  • ASN1_digest(), ASN1_sign(), ASN1_verify()

There are no replacements, bestie. These old functions are literally not used, and you could disable them with the macro NO_ASN1_OLD since OpenSSL 0.9.7. 💀

  • ASN1_STRING_length_set() — use ASN1_STRING_set(3) or ASN1_STRING_set0(3) instead. This was a potentially unsafe function that could change the bounds of a previously passed in pointer. ⚠️ So not it, periodt.
  • BF_encrypt(), BF_decrypt(), BF_set_key(), BF_cbc_encrypt(), BF_cfb64_encrypt(), BF_ecb_encrypt(), BF_ofb64_encrypt() — see the "Deprecated low-level encryption functions" section. The Blowfish algorithm has been moved to the Legacy Provider. 🐡 Lowkey iconic but deprecated.
  • BF_options() — there is no replacement. This option returned a constant string. 💁‍♀️ It's giving useless.
  • BIO_get_callback(), BIO_set_callback(), BIO_debug_callback() — use the respective non-deprecated _ex() functions. ✨ Slay.
  • BN_is_prime_ex(), BN_is_prime_fasttest_ex() — use BN_check_prime(3) which avoids possible misuse and always uses at least 64 rounds of the Miller-Rabin primality test. 🔢 That's a lot of rounds, fr fr.
  • BN_pseudo_rand(), BN_pseudo_rand_range() — use BN_rand(3) and BN_rand_range(3). 🎲
  • BN_X931_derive_prime_ex(), BN_X931_generate_prime_ex(), BN_X931_generate_Xpq() — there are no replacements for these low-level functions. They were used internally by RSA_X931_derive_ex() and RSA_X931_generate_key_ex() which are also deprecated. Use EVP_PKEY_keygen(3) instead. 👑 Main character energy.
  • Camellia_encrypt(), Camellia_decrypt(), Camellia_set_key(), Camellia_cbc_encrypt(), Camellia_cfb128_encrypt(), Camellia_cfb1_encrypt(), Camellia_cfb8_encrypt(), Camellia_ctr128_encrypt(), Camellia_ecb_encrypt(), Camellia_ofb128_encrypt() — see the "Deprecated low-level encryption functions" section. 🌸 Still cute though.
  • CAST_encrypt(), CAST_decrypt(), CAST_set_key(), CAST_cbc_encrypt(), CAST_cfb64_encrypt(), CAST_ecb_encrypt(), CAST_ofb64_encrypt() — see the "Deprecated low-level encryption functions" section. The CAST algorithm has been moved to the Legacy Provider. 🏰 It's giving legacy.
  • CMAC_CTX_new(), CMAC_CTX_cleanup(), CMAC_CTX_copy(), CMAC_CTX_free(), CMAC_CTX_get0_cipher_ctx() — see the "Deprecated low-level MAC functions" section. 🔐 No cap.
  • CMAC_Init(), CMAC_Update(), CMAC_Final(), CMAC_resume() — see the "Deprecated low-level MAC functions" section. 🔐
  • CRYPTO_mem_ctrl(), CRYPTO_mem_debug_free(), CRYPTO_mem_debug_malloc(), CRYPTO_mem_debug_pop(), CRYPTO_mem_debug_push(), CRYPTO_mem_debug_realloc(), CRYPTO_mem_leaks(), CRYPTO_mem_leaks_cb(), CRYPTO_mem_leaks_fp(), CRYPTO_set_mem_debug() — memory-leak checking has been deprecated in favor of more modern development tools, such as compiler memory and leak sanitizers or Valgrind. 🧼 Periodt, use Valgrind.
  • CRYPTO_cts128_encrypt_block(), CRYPTO_cts128_encrypt(), CRYPTO_cts128_decrypt_block(), CRYPTO_cts128_decrypt(), CRYPTO_nistcts128_encrypt_block(), CRYPTO_nistcts128_encrypt(), CRYPTO_nistcts128_decrypt_block(), CRYPTO_nistcts128_decrypt() — use the higher level functions EVP_CipherInit_ex2(), EVP_CipherUpdate() and EVP_CipherFinal_ex() instead. See the "cts_mode" parameter in "Gettable and Settable EVP_CIPHER_CTX parameters" in EVP_EncryptInit(3). See "EXAMPLES" in EVP_EncryptInit(3) for a AES-256-CBC-CTS example. 🧩 You got this.
  • d2i_DHparams(), d2i_DHxparams(), d2i_DSAparams(), d2i_DSAPrivateKey(), d2i_DSAPrivateKey_bio(), d2i_DSAPrivateKey_fp(), d2i_DSA_PUBKEY(), d2i_DSA_PUBKEY_bio(), d2i_DSA_PUBKEY_fp(), d2i_DSAPublicKey(), d2i_ECParameters(), d2i_ECPrivateKey(), d2i_ECPrivateKey_bio(), d2i_ECPrivateKey_fp(), d2i_EC_PUBKEY(), d2i_EC_PUBKEY_bio(), d2i_EC_PUBKEY_fp(), d2i_RSAPrivateKey(), d2i_RSAPrivateKey_bio(), d2i_RSAPrivateKey_fp(), d2i_RSA_PUBKEY(), d2i_RSA_PUBKEY_bio(), d2i_RSA_PUBKEY_fp(), d2i_RSAPublicKey(), d2i_RSAPublicKey_bio(), d2i_RSAPublicKey_fp() — see the "Deprecated i2d and d2i functions for low-level key types" section. 📦 It's a whole vibe.
  • o2i_ECPublicKey() — use EVP_PKEY_set1_encoded_public_key(3). See the "Deprecated low-level key parameter setters" section. 🔑
  • DES_crypt(), DES_fcrypt(), DES_encrypt1(), DES_encrypt2(), DES_encrypt3(), DES_decrypt3(), DES_ede3_cbc_encrypt(), DES_ede3_cfb64_encrypt(), DES_ede3_cfb_encrypt(),DES_ede3_ofb64_encrypt(), DES_ecb_encrypt(), DES_ecb3_encrypt(), DES_ofb64_encrypt(), DES_ofb_encrypt(), DES_cfb64_encrypt DES_cfb_encrypt(), DES_cbc_encrypt(), DES_ncbc_encrypt(), DES_pcbc_encrypt(), DES_xcbc_encrypt(), DES_cbc_cksum(), DES_quad_cksum(), DES_check_key_parity(), DES_is_weak_key(), DES_key_sched(), DES_options(), DES_random_key(), DES_set_key(), DES_set_key_checked(), DES_set_key_unchecked(), DES_set_odd_parity(), DES_string_to_2keys(), DES_string_to_key() — see the "Deprecated low-level encryption functions" section. Algorithms for "DESX-CBC", "DES-ECB", "DES-CBC", "DES-OFB", "DES-CFB", "DES-CFB1" and "DES-CFB8" have been moved to the Legacy Provider. 🔒 That's a lot of algorithms, bestie.
  • DH_bits(), DH_security_bits(), DH_size() — use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and EVP_PKEY_get_size(3). 📏 Easy.
  • DH_check(), DH_check_ex(), DH_check_params(), DH_check_params_ex(), DH_check_pub_key(), DH_check_pub_key_ex() — see the "Deprecated low-level validation functions" section. ✅
  • DH_clear_flags(), DH_test_flags(), DH_set_flags() — the DH_FLAG_CACHE_MONT_P flag has been deprecated without replacement. The DH_FLAG_TYPE_DH and DH_FLAG_TYPE_DHX have been deprecated. Use EVP_PKEY_is_a() to determine the type of a key. There is no replacement for setting these flags. 🚩 So don't set them, periodt.
  • DH_compute_key() DH_compute_key_padded() — see the "Deprecated low-level key exchange functions" section. 🔄
  • DH_new(), DH_new_by_nid(), DH_free(), DH_up_ref() — see the "Deprecated low-level object creation" section. 🆕
  • DH_generate_key(), DH_generate_parameters_ex() — see the "Deprecated low-level key generation functions" section. 🔧
  • DH_get0_pqg(), DH_get0_p(), DH_get0_q(), DH_get0_g(), DH_get0_key(), DH_get0_priv_key(), DH_get0_pub_key(), DH_get_length(), DH_get_nid() — see the "Deprecated low-level key parameter getters" section. 🔍
  • DH_get_1024_160(), DH_get_2048_224(), DH_get_2048_256() — applications should instead set the OSSL_PKEY_PARAM_GROUP_NAME as specified in "DH parameters" in EVP_PKEY-DH(7)) to one of "dh_1024_160", "dh_2048_224" or "dh_2048_256" when generating a DH key. 🎯
  • DH_KDF_X9_42() — applications should use EVP_PKEY_CTX_set_dh_kdf_type(3) instead. 🔑
  • DH_get_default_method(), DH_get0_engine(), DH_meth_*(), DH_new_method(), DH_OpenSSL(), DH_get_ex_data(), DH_set_default_method(), DH_set_method(), DH_set_ex_data() — see the "Providers are a replacement for engines and low-level method overrides" section. 🏭
  • DHparams_print(), DHparams_print_fp() — see the "Deprecated low-level key printing functions" section. 🖨️
  • DH_set0_key(), DH_set0_pqg(), DH_set_length() — see the "Deprecated low-level key parameter setters" section. ✍️
  • DSA_bits(), DSA_security_bits(), DSA_size() — use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and EVP_PKEY_get_size(3). 📏
  • DHparams_dup(), DSA_dup_DH() — there is no direct replacement. Applications may use EVP_PKEY_copy_parameters(3) and EVP_PKEY_dup(3) instead. 📋
  • DSA_generate_key(), DSA_generate_parameters_ex() — see the "Deprecated low-level key generation functions" section. 🔧
  • DSA_get0_engine(), DSA_get_default_method(), DSA_get_ex_data(), DSA_get_method(), DSA_meth_*(), DSA_new_method(), DSA_OpenSSL(), DSA_set_default_method(), DSA_set_ex_data(), DSA_set_method() — see the "Providers are a replacement for engines and low-level method overrides" section. 🏭
  • DSA_get0_p(), DSA_get0_q(), DSA_get0_g(), DSA_get0_pqg(), DSA_get0_key(), DSA_get0_priv_key(), DSA_get0_pub_key() — see the "Deprecated low-level key parameter getters" section. 🔍
  • DSA_new(), DSA_free(), DSA_up_ref() — see the "Deprecated low-level object creation" section. 🆕
  • DSAparams_dup() — there is no direct replacement. Applications may use EVP_PKEY_copy_parameters(3) and EVP_PKEY_dup(3) instead. 📋
  • DSAparams_print(), DSAparams_print_fp(), DSA_print(), DSA_print_fp() — see the "Deprecated low-level key printing functions" section. 🖨️
  • DSA_set0_key(), DSA_set0_pqg() — see the "Deprecated low-level key parameter setters" section. ✍️
  • DSA_set_flags(), DSA_clear_flags(), DSA_test_flags() — the DSA_FLAG_CACHE_MONT_P flag has been deprecated without replacement. 🚩
  • DSA_sign(), DSA_do_sign(), DSA_sign_setup(), DSA_verify(), DSA_do_verify() — see the "Deprecated low-level signing functions" section. ✍️
  • ECDH_compute_key() — see the "Deprecated low-level key exchange functions" section. 🔄
  • ECDH_KDF_X9_62() — applications may either set this using the helper function EVP_PKEY_CTX_set_ecdh_kdf_type(3) or by setting an OSSL_PARAM(3) using the "kdf-type" as shown in "EXAMPLES" in EVP_KEYEXCH-ECDH(7). 🔑
  • ECDSA_sign(), ECDSA_sign_ex(), ECDSA_sign_setup(), ECDSA_do_sign(), ECDSA_do_sign_ex(), ECDSA_verify(), ECDSA_do_verify() — see the "Deprecated low-level signing functions" section. ✍️
  • ECDSA_size() — applications should use EVP_PKEY_get_size(3). 📏
  • EC_GF2m_simple_method(), EC_GFp_mont_method(), EC_GFp_nist_method(), EC_GFp_nistp224_method(), EC_GFp_nistp256_method(), EC_GFp_nistp521_method(), EC_GFp_simple_method() — there are no replacements for these functions. Applications should rely on the library automatically assigning a suitable method internally when an EC_GROUP is constructed. 🌐 Trust the library.
  • EC_GROUP_clear_free() — use EC_GROUP_free(3) instead. 🧹
  • EC_GROUP_get_curve_GF2m(), EC_GROUP_get_curve_GFp(), EC_GROUP_set_curve_GF2m(), EC_GROUP_set_curve_GFp() — applications should use EC_GROUP_get_curve(3) and EC_GROUP_set_curve(3). 📈
  • EC_GROUP_have_precompute_mult(), EC_GROUP_precompute_mult(), EC_KEY_precompute_mult() — these functions are not widely used. Applications should instead switch to named curves which OpenSSL has hardcoded lookup tables for. 📊 Lowkey optimized.
  • EC_GROUP_new(), EC_GROUP_method_of(), EC_POINT_method_of() — EC_METHOD is now an internal-only concept and a suitable EC_METHOD is assigned internally without application intervention. Users of EC_GROUP_new() should switch to a different suitable constructor. 🏗️
  • EC_KEY_can_sign() — applications should use EVP_PKEY_can_sign(3) instead. ✍️
  • EC_KEY_check_key() — see the "Deprecated low-level validation functions" section. ✅
  • EC_KEY_set_flags(), EC_KEY_get_flags(), EC_KEY_clear_flags()
  • the EC flag situation — see "Common EC parameters" in EVP_PKEY-EC(7), which handles flags as separate parameters for OSSL_PKEY_PARAM_EC_POINT_CONVERSION_FORMAT, OSSL_PKEY_PARAM_EC_GROUP_CHECK_TYPE, OSSL_PKEY_PARAM_EC_ENCODING, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH and OSSL_PKEY_PARAM_EC_INCLUDE_PUBLIC. See also "EXAMPLES" in EVP_PKEY-EC(7) ✨
  • EC_KEY_dup(), EC_KEY_copy() — bestie, there's no direct replacement 😭. Apps may use EVP_PKEY_copy_parameters(3) and EVP_PKEY_dup(3) instead.
  • EC_KEY_decoded_from_explicit_params() — no replacement. That's it. That's the whole vibe check. 💀
  • EC_KEY_generate_key() — see "Deprecated low-level key generation functions".
  • EC_KEY_get0_group(), EC_KEY_get0_private_key(), EC_KEY_get0_public_key(), EC_KEY_get_conv_form(), EC_KEY_get_enc_flags() — see "Deprecated low-level key parameter getters".
  • EC_KEY_get0_engine(), EC_KEY_get_default_method(), EC_KEY_get_method(), EC_KEY_new_method(), EC_KEY_get_ex_data(), EC_KEY_OpenSSL(), EC_KEY_set_ex_data(), EC_KEY_set_default_method(), EC_KEY_METHOD_*(), EC_KEY_set_method() — see "Providers are a replacement for engines and low-level method overrides".
  • EC_METHOD_get_field_type() — use EC_GROUP_get_field_type(3) instead, okurrr? See "Providers are a replacement for engines and low-level method overrides".
  • EC_KEY_key2buf(), EC_KEY_oct2key(), EC_KEY_oct2priv(), EC_KEY_priv2buf(), EC_KEY_priv2oct() — literally no replacements for these 🙈.
  • EC_KEY_new(), EC_KEY_new_by_curve_name(), EC_KEY_free(), EC_KEY_up_ref() — see "Deprecated low-level object creation".
  • EC_KEY_print(), EC_KEY_print_fp() — see "Deprecated low-level key printing functions".
  • EC_KEY_set_asn1_flag(), EC_KEY_set_conv_form(), EC_KEY_set_enc_flags() — see "Deprecated low-level key parameter setters".
  • EC_KEY_set_group(), EC_KEY_set_private_key(), EC_KEY_set_public_key(), EC_KEY_set_public_key_affine_coordinates() — see "Deprecated low-level key parameter setters".
  • ECParameters_print(), ECParameters_print_fp(), ECPKParameters_print(), ECPKParameters_print_fp() — see "Deprecated low-level key printing functions".
  • EC_POINT_bn2point(), EC_POINT_point2bn() — ngl these were not particularly useful, since EC point serialization formats are not individual big-endian integers. Like, the math wasn't mathing 💅.
  • EC_POINT_get_affine_coordinates_GF2m(), EC_POINT_get_affine_coordinates_GFp(), EC_POINT_set_affine_coordinates_GF2m(), EC_POINT_set_affine_coordinates_GFp() — apps should use EC_POINT_get_affine_coordinates(3) and EC_POINT_set_affine_coordinates(3) instead 🫶.
  • EC_POINT_get_Jprojective_coordinates_GFp(), EC_POINT_set_Jprojective_coordinates_GFp() — these functions are not widely used. Applications should instead use the EC_POINT_set_affine_coordinates(3) and EC_POINT_get_affine_coordinates(3) functions ✨.
  • EC_POINT_make_affine(), EC_POINTs_make_affine() — there is no replacement. These were not widely used, and OpenSSL automatically performs this conversion when needed — so the library literally does it for you, main character energy 👑.
  • EC_POINT_set_compressed_coordinates_GF2m(), EC_POINT_set_compressed_coordinates_GFp() — applications should use EC_POINT_set_compressed_coordinates(3) instead.
  • EC_POINTs_mul() — not widely used, bestie. Applications should instead use the EC_POINT_mul(3) function 💖.
  • ENGINE_*() — all engine functions are deprecated, periodt. An engine should be rewritten as a provider. See "Providers are a replacement for engines and low-level method overrides" 🔥.
  • ERR_load_*(), ERR_func_error_string(), ERR_get_error_line(), ERR_get_error_line_data(), ERR_get_state() — OpenSSL now loads error strings automatically, so these functions are simply not needed. Slay, less boilerplate for us 🌸.
  • ERR_peek_error_line_data(), ERR_peek_last_error_line_data() — the new functions are ERR_peek_error_func(3), ERR_peek_last_error_func(3), ERR_peek_error_data(3), ERR_peek_last_error_data(3), ERR_get_error_all(3), ERR_peek_error_all(3) and ERR_peek_last_error_all(3). Applications should use ERR_get_error_all(3), or pick information with ERR_peek functions and finish off with getting the error code by using ERR_get_error(3) 🎀.
  • EVP_CIPHER_CTX_iv(), EVP_CIPHER_CTX_iv_noconst(), EVP_CIPHER_CTX_original_iv() — applications should instead use EVP_CIPHER_CTX_get_updated_iv(3), EVP_CIPHER_CTX_get_updated_iv(3) and EVP_CIPHER_CTX_get_original_iv(3) respectively. (Yes, EVP_CIPHER_CTX_get_updated_iv(3) shows up twice up there — that's literally what the manpage says, don't come for me 😭.) See EVP_CIPHER_CTX_get_original_iv(3) for further information.
  • EVP_CIPHER_meth_*(), EVP_MD_CTX_set_update_fn(), EVP_MD_CTX_update_fn(), EVP_MD_meth_*() — see "Providers are a replacement for engines and low-level method overrides".
  • EVP_PKEY_CTRL_PKCS7_ENCRYPT(), EVP_PKEY_CTRL_PKCS7_DECRYPT(), EVP_PKEY_CTRL_PKCS7_SIGN(), EVP_PKEY_CTRL_CMS_ENCRYPT(), EVP_PKEY_CTRL_CMS_DECRYPT(), and EVP_PKEY_CTRL_CMS_SIGN() — these control operations are not invoked by the OpenSSL library anymore and are replaced by direct checks of the key operation against the key type when the operation is initialized 🦋.
  • EVP_PKEY_CTX_get0_dh_kdf_ukm(), EVP_PKEY_CTX_get0_ecdh_kdf_ukm() — see the "kdf-ukm" item in "DH key exchange parameters" in EVP_KEYEXCH-DH(7) and "ECDH Key Exchange parameters" in EVP_KEYEXCH-ECDH(7). These functions are obsolete and should not be required 💜.
  • EVP_PKEY_CTX_set_rsa_keygen_pubexp() — applications should use EVP_PKEY_CTX_set1_rsa_keygen_pubexp(3) instead. Notice the little 1 in there, she matters 👀.
  • EVP_PKEY_cmp(), EVP_PKEY_cmp_parameters() — applications should use EVP_PKEY_eq(3) and EVP_PKEY_parameters_eq(3) instead. See EVP_PKEY_copy_parameters(3) for further details ✨.
  • EVP_PKEY_encrypt_old(), EVP_PKEY_decrypt_old() — applications should use EVP_PKEY_encrypt_init(3) and EVP_PKEY_encrypt(3) or EVP_PKEY_decrypt_init(3) and EVP_PKEY_decrypt(3) instead.
  • EVP_PKEY_get0() — heads up: this function returns NULL if the key comes from a provider. Like, that's the whole personality trait 😬.
  • EVP_PKEY_get0_DH(), EVP_PKEY_get0_DSA(), EVP_PKEY_get0_EC_KEY(), EVP_PKEY_get0_RSA(), EVP_PKEY_get1_DH(), EVP_PKEY_get1_DSA(), EVP_PKEY_get1_EC_KEY and EVP_PKEY_get1_RSA(), EVP_PKEY_get0_hmac(), EVP_PKEY_get0_poly1305(), EVP_PKEY_get0_siphash() — see "Functions that return an internal key should be treated as read only". No touching, only looking 🙅‍♀️.
  • EVP_PKEY_meth_*() — see "Providers are a replacement for engines and low-level method overrides".
  • EVP_PKEY_new_CMAC_key() — see "Deprecated low-level MAC functions".
  • EVP_PKEY_assign(), EVP_PKEY_set1_DH(), EVP_PKEY_set1_DSA(), EVP_PKEY_set1_EC_KEY(), EVP_PKEY_set1_RSA() — see "Deprecated low-level key object getters and setters".
  • EVP_PKEY_set1_tls_encodedpoint() EVP_PKEY_get1_tls_encodedpoint() — these were previously used by libssl to set or get an encoded public key into/from an EVP_PKEY object. With OpenSSL 3.0 these are replaced by the more generic functions EVP_PKEY_set1_encoded_public_key(3) and EVP_PKEY_get1_encoded_public_key(3). The old versions have been converted to deprecated macros that just call the new functions — glow-up complete 💅✨.
  • EVP_PKEY_set1_engine(), EVP_PKEY_get0_engine() — see "Providers are a replacement for engines and low-level method overrides".
  • EVP_PKEY_set_alias_type() — this function has been removed. There is no replacement. See "EVP_PKEY_set_alias_type() method has been removed" 💀.
  • HMAC_Init_ex(), HMAC_Update(), HMAC_Final(), HMAC_size() — see "Deprecated low-level MAC functions".
  • HMAC_CTX_new(), HMAC_CTX_free(), HMAC_CTX_copy(), HMAC_CTX_reset(), HMAC_CTX_set_flags(), HMAC_CTX_get_md() — see "Deprecated low-level MAC functions".
  • i2d_DHparams(), i2d_DHxparams() — see "Deprecated low-level key reading and writing functions" and "Migration" in d2i_RSAPrivateKey(3).
  • i2d_DSAparams(), i2d_DSAPrivateKey(), i2d_DSAPrivateKey_bio(), i2d_DSAPrivateKey_fp(), i2d_DSA_PUBKEY(), i2d_DSA_PUBKEY_bio(), i2d_DSA_PUBKEY_fp(), i2d_DSAPublicKey() — see "Deprecated low-level key reading and writing functions" and "Migration" in d2i_RSAPrivateKey(3).
  • i2d_ECParameters(), i2d_ECPrivateKey(), i2d_ECPrivateKey_bio(), i2d_ECPrivateKey_fp(), i2d_EC_PUBKEY(), i2d_EC_PUBKEY_bio(), i2d_EC_PUBKEY_fp() — see "Deprecated low-level key reading and writing functions" and "Migration" in d2i_RSAPrivateKey(3).
  • i2o_ECPublicKey() — use EVP_PKEY_get1_encoded_public_key(3). See "Deprecated low-level key parameter getters".
  • i2d_RSAPrivateKey(), i2d_RSAPrivateKey_bio(), i2d_RSAPrivateKey_fp(), i2d_RSA_PUBKEY(), i2d_RSA_PUBKEY_bio(), i2d_RSA_PUBKEY_fp(), i2d_RSAPublicKey(), i2d_RSAPublicKey_bio(), i2d_RSAPublicKey_fp() — see "Deprecated low-level key reading and writing functions" and "Migration" in d2i_RSAPrivateKey(3).
  • IDEA_encrypt(), IDEA_set_decrypt_key(), IDEA_set_encrypt_key(), IDEA_cbc_encrypt(), IDEA_cfb64_encrypt(), IDEA_ecb_encrypt(), IDEA_ofb64_encrypt() — see "Deprecated low-level encryption functions". IDEA has been moved to the Legacy Provider 📦.
  • IDEA_options() — there is no replacement. This function returned a constant string, so like… it was giving nothing anyway 🍓.
  • MD2(), MD2_Init(), MD2_Update(), MD2_Final() — see "Deprecated low-level encryption functions". MD2 has been moved to the Legacy Provider 📦.
  • MD2_options() — no replacement. This function returned a constant string. Same story 🎀.
  • MD4(), MD4_Init(), MD4_Update(), MD4_Final(), MD4_Transform() — see "Deprecated low-level encryption functions". MD4 has been moved to the Legacy Provider 📦.
  • MDC2(), MDC2_Init(), MDC2_Update(), MDC2_Final() — see "Deprecated low-level encryption functions". MDC2 has been moved to the Legacy Provider 📦.
  • MD5(), MD5_Init(), MD5_Update(), MD5_Final(), MD5_Transform() — see "Deprecated low-level encryption functions".
  • NCONF_WIN32() — this undocumented function has no replacement. See "HISTORY" in config(5) for more details 🦋.
  • OCSP_parse_url() — use OSSL_HTTP_parse_url(3) instead.
  • OCSP_REQ_CTX type and OCSP_REQ_CTX_*() functions — these methods were used to collect all necessary data to form a HTTP request, and to perform the HTTP transfer with that request. With OpenSSL 3.0, the type is OSSL_HTTP_REQ_CTX, and the deprecated functions are replaced with OSSL_HTTP_REQ_CTX_*(). See OSSL_HTTP_REQ_CTX(3) for additional details 💜.
  • OPENSSL_fork_child(), OPENSSL_fork_parent(), OPENSSL_fork_prepare()

No replacement exists, and honestly? Nothing to migrate, bestie. These pthread fork support methods were unused by OpenSSL. So they just... vibe off into the sunset. 🌅

  • OSSL_STORE_ctrl(), OSSL_STORE_do_all_loaders(), OSSL_STORE_LOADER_get0_engine(), OSSL_STORE_LOADER_get0_scheme(), OSSL_STORE_LOADER_new(), OSSL_STORE_LOADER_set_attach(), OSSL_STORE_LOADER_set_close(), OSSL_STORE_LOADER_set_ctrl(), OSSL_STORE_LOADER_set_eof(), OSSL_STORE_LOADER_set_error(), OSSL_STORE_LOADER_set_expect(), OSSL_STORE_LOADER_set_find(), OSSL_STORE_LOADER_set_load(), OSSL_STORE_LOADER_set_open(), OSSL_STORE_LOADER_set_open_ex(), OSSL_STORE_register_loader(), OSSL_STORE_unregister_loader(), OSSL_STORE_vctrl()

These helped applications and engines create loaders for schemes they supported. They're all deprecated now and actively discouraged — provider implementations are the whole personality going forward, so see provider-storemgmt(7). ✨

  • PEM_read_DHparams(), PEM_read_bio_DHparams(), PEM_read_DSAparams(), PEM_read_bio_DSAparams(), PEM_read_DSAPrivateKey(), PEM_read_DSA_PUBKEY(), PEM_read_bio_DSAPrivateKey and PEM_read_bio_DSA_PUBKEY(), PEM_read_ECPKParameters(), PEM_read_ECPrivateKey(), PEM_read_EC_PUBKEY(), PEM_read_bio_ECPKParameters(), PEM_read_bio_ECPrivateKey(), PEM_read_bio_EC_PUBKEY(), PEM_read_RSAPrivateKey(), PEM_read_RSA_PUBKEY(), PEM_read_RSAPublicKey(), PEM_read_bio_RSAPrivateKey(), PEM_read_bio_RSA_PUBKEY(), PEM_read_bio_RSAPublicKey(), PEM_write_bio_DHparams(), PEM_write_bio_DHxparams(), PEM_write_DHparams(), PEM_write_DHxparams(), PEM_write_DSAparams(), PEM_write_DSAPrivateKey(), PEM_write_DSA_PUBKEY(), PEM_write_bio_DSAparams(), PEM_write_bio_DSAPrivateKey(), PEM_write_bio_DSA_PUBKEY(), PEM_write_ECPKParameters(), PEM_write_ECPrivateKey(), PEM_write_EC_PUBKEY(), PEM_write_bio_ECPKParameters(), PEM_write_bio_ECPrivateKey(), PEM_write_bio_EC_PUBKEY(), PEM_write_RSAPrivateKey(), PEM_write_RSA_PUBKEY(), PEM_write_RSAPublicKey(), PEM_write_bio_RSAPrivateKey(), PEM_write_bio_RSA_PUBKEY(), PEM_write_bio_RSAPublicKey()

See "Deprecated low-level key reading and writing functions" — that's the glow-up spot. 📖

  • PKCS1_MGF1()

See "Deprecated low-level encryption functions".

  • RAND_get_rand_method(), RAND_set_rand_method(), RAND_OpenSSL(), RAND_set_rand_engine()

Applications should use RAND_set_DRBG_type(3), EVP_RAND(3) and EVP_RAND(7) instead. RAND_set_rand_method(3) has the full tea for more details. ☕

  • RC2_encrypt(), RC2_decrypt(), RC2_set_key(), RC2_cbc_encrypt(), RC2_cfb64_encrypt(), RC2_ecb_encrypt(), RC2_ofb64_encrypt(), RC4(), RC4_set_key(), RC4_options(), RC5_32_encrypt(), RC5_32_set_key(), RC5_32_decrypt(), RC5_32_cbc_encrypt(), RC5_32_cfb64_encrypt(), RC5_32_ecb_encrypt(), RC5_32_ofb64_encrypt()

See "Deprecated low-level encryption functions". Heads up: the algorithms "RC2", "RC4" and "RC5" have been moved to the Legacy Provider. 🏚️

  • RIPEMD160(), RIPEMD160_Init(), RIPEMD160_Update(), RIPEMD160_Final(), RIPEMD160_Transform()

See "Deprecated low-level digest functions". The RIPE algorithm has been moved to the Legacy Provider too.

  • RSA_bits(), RSA_security_bits(), RSA_size()

Use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and EVP_PKEY_get_size(3). Slay. 💅

  • RSA_check_key(), RSA_check_key_ex()

See "Deprecated low-level validation functions".

  • RSA_clear_flags(), RSA_flags(), RSA_set_flags(), RSA_test_flags(), RSA_setup_blinding(), RSA_blinding_off(), RSA_blinding_on()

All of these RSA flags have been deprecated without replacement:

RSA_FLAG_BLINDING, RSA_FLAG_CACHE_PRIVATE, RSA_FLAG_CACHE_PUBLIC, RSA_FLAG_EXT_PKEY, RSA_FLAG_NO_BLINDING, RSA_FLAG_THREAD_SAFE, RSA_METHOD_FLAG_NO_CHECK

  • RSA_generate_key_ex(), RSA_generate_multi_prime_key()

See "Deprecated low-level key generation functions".

  • RSA_get0_engine()

See "Providers are a replacement for engines and low-level method overrides".

  • RSA_get0_crt_params(), RSA_get0_d(), RSA_get0_dmp1(), RSA_get0_dmq1(), RSA_get0_e(), RSA_get0_factors(), RSA_get0_iqmp(), RSA_get0_key(), RSA_get0_multi_prime_crt_params(), RSA_get0_multi_prime_factors(), RSA_get0_n(), RSA_get0_p(), RSA_get0_pss_params(), RSA_get0_q(), RSA_get_multi_prime_extra_count()

See "Deprecated low-level key parameter getters".

  • RSA_new(), RSA_free(), RSA_up_ref()

See "Deprecated low-level object creation".

  • RSA_get_default_method(), RSA_get_ex_data and RSA_get_method()

See "Providers are a replacement for engines and low-level method overrides".

  • RSA_get_version()

There is no replacement. Genuinely none. 😭

  • RSA_meth_*(), RSA_new_method(), RSA_null_method and RSA_PKCS1_OpenSSL()

See "Providers are a replacement for engines and low-level method overrides".

  • RSA_padding_add_*(), RSA_padding_check_*()

See "Deprecated low-level signing functions" and "Deprecated low-level encryption functions".

  • RSA_print(), RSA_print_fp()

See "Deprecated low-level key printing functions".

  • RSA_public_encrypt(), RSA_private_decrypt()

See "Deprecated low-level encryption functions".

  • RSA_private_encrypt(), RSA_public_decrypt()

This is equivalent to doing sign and verify recover operations (with a padding mode of none). See "Deprecated low-level signing functions".

  • RSAPrivateKey_dup(), RSAPublicKey_dup()

There is no direct replacement. Applications may use EVP_PKEY_dup(3) though. 🫶

  • RSAPublicKey_it(), RSAPrivateKey_it()

See "Deprecated low-level key reading and writing functions".

  • RSA_set0_crt_params(), RSA_set0_factors(), RSA_set0_key(), RSA_set0_multi_prime_params()

See "Deprecated low-level key parameter setters".

  • RSA_set_default_method(), RSA_set_method(), RSA_set_ex_data()

See "Providers are a replacement for engines and low-level method overrides".

  • RSA_sign(), RSA_sign_ASN1_OCTET_STRING(), RSA_verify(), RSA_verify_ASN1_OCTET_STRING(), RSA_verify_PKCS1_PSS(), RSA_verify_PKCS1_PSS_mgf1()

See "Deprecated low-level signing functions".

  • RSA_X931_derive_ex(), RSA_X931_generate_key_ex(), RSA_X931_hash_id()

There are no replacements for these functions. X931 padding can be set using "Signature Parameters" in EVP_SIGNATURE-RSA(7). See OSSL_SIGNATURE_PARAM_PAD_MODE.

  • SEED_encrypt(), SEED_decrypt(), SEED_set_key(), SEED_cbc_encrypt(), SEED_cfb128_encrypt(), SEED_ecb_encrypt(), SEED_ofb128_encrypt()

See "Deprecated low-level encryption functions". The SEED algorithm has been moved to the Legacy Provider.

  • SHA1_Init(), SHA1_Update(), SHA1_Final(), SHA1_Transform(), SHA224_Init(), SHA224_Update(), SHA224_Final(), SHA256_Init(), SHA256_Update(), SHA256_Final(), SHA256_Transform(), SHA384_Init(), SHA384_Update(), SHA384_Final(), SHA512_Init(), SHA512_Update(), SHA512_Final(), SHA512_Transform()

See "Deprecated low-level digest functions".

  • SRP_Calc_A(), SRP_Calc_B(), SRP_Calc_client_key(), SRP_Calc_server_key(), SRP_Calc_u(), SRP_Calc_x(), SRP_check_known_gN_param(), SRP_create_verifier(), SRP_create_verifier_BN(), SRP_get_default_gN(), SRP_user_pwd_free(), SRP_user_pwd_new(), SRP_user_pwd_set0_sv(), SRP_user_pwd_set1_ids(), SRP_user_pwd_set_gN(), SRP_VBASE_add0_user(), SRP_VBASE_free(), SRP_VBASE_get1_by_user(), SRP_VBASE_init(), SRP_VBASE_new(), SRP_Verify_A_mod_N(), SRP_Verify_B_mod_N()

There are no replacements for the SRP functions. That's it, that's the whole note. 💀

  • SSL_CTX_set_tmp_dh_callback(), SSL_set_tmp_dh_callback(), SSL_CTX_set_tmp_dh(), SSL_set_tmp_dh()

These set the Diffie-Hellman (DH) parameters that servers requiring ephemeral DH keys use. Instead, applications should consider using the built-in DH parameters available by calling SSL_CTX_set_dh_auto(3) or SSL_set_dh_auto(3). If custom parameters are genuinely necessary, applications can use the alternative functions SSL_CTX_set0_tmp_dh_pkey(3) and SSL_set0_tmp_dh_pkey(3). There is no direct replacement for the "callback" functions — the callback was originally useful in order to have different parameters for export and non-export ciphersuites, and export ciphersuites are no longer supported by OpenSSL. Use of the callback functions should be replaced by one of the other methods described above. 🧚

  • SSL_CTX_set_tlsext_ticket_key_cb()

Use the new SSL_CTX_set_tlsext_ticket_key_evp_cb(3) function instead.

  • WHIRLPOOL(), WHIRLPOOL_Init(), WHIRLPOOL_Update(), WHIRLPOOL_Final(), WHIRLPOOL_BitUpdate()

See "Deprecated low-level digest functions". The Whirlpool algorithm has been moved to the Legacy Provider.

  • X509_certificate_type()

This was an undocumented function. Applications can use X509_get0_pubkey(3) and X509_get0_signature(3) instead.

  • X509_http_nbio(), X509_CRL_http_nbio()

Use X509_load_http(3) and X509_CRL_load_http(3) instead.

📇 NID handling for provided keys and algorithms

The following functions for NID (numeric id) handling have changed semantics. Note that this is changed, not deprecated — read carefully, bestie. 👀

  • EVP_PKEY_id(), EVP_PKEY_get_id()

This function was previously used to reliably return the NID of an EVP_PKEY object, e.g., to look up the name of the algorithm of such EVP_PKEY by calling OBJ_nid2sn(3). With the introduction of provider(7)s, EVP_PKEY_id() or its new equivalent EVP_PKEY_get_id(3) might now also return the value -1 (EVP_PKEY_KEYMGMT), which indicates the use of a provider to implement the EVP_PKEY object. So the use of EVP_PKEY_get0_type_name(3) is recommended for retrieving the name of the EVP_PKEY algorithm. Iconic behaviour, honestly. 🌈

🔐 Using the FIPS Module in applications

See fips_module(7) and OSSL_PROVIDER-FIPS(7) for details.

💻 OpenSSL command line application changes

✨ New applications

openssl kdf uses the new EVP_KDF(3) API. And the page also tells you openssl kdf uses the new EVP_MAC(3) API — that's verbatim what it says, so write it down exactly like that. 🫶

➕ Added options

-provider_path and -provider are available to all apps and can be used multiple times to load any providers, such as the 'legacy' provider or third party providers. If used, then the 'default' provider would also need to be specified if required. The -provider_path must be specified before the -provider option — order matters, bestie. ⚠️

The list app has many new options. See openssl-list(1) for more information.

-crl_lastupdate and -crl_nextupdate used by openssl ca allow explicit setting of fields in the generated CRL.

➖ Removed options

Interactive mode is no longer available. Gone. Packed up. 🎀

  • -crypt — used by openssl passwd. And -c — used by openssl x509, openssl dhparam, openssl dsaparam, and openssl ecparam. (Yep, that's the list, bestie 💅.)

✨ Other Changes ✨

The output of Command line applications may have minor changes. These are primarily changes in capitalisation and white space. However, in some cases, there are additional differences. For example, the DH parameters output from openssl dhparam now lists 'P', 'Q', 'G' and 'pcounter' instead of 'prime', 'generator', 'subgroup order' and 'counter' respectively.

The openssl commands that read keys, certificates, and CRLs now automatically detect the PEM or DER format of the input files so it is not necessary to explicitly specify the input format anymore. However if the input format option is used the specified format will be required.

openssl speed no longer uses low-level API calls. This implies some of the performance numbers might not be comparable with the previous releases due to higher overhead. This applies particularly to measuring performance on smaller data chunks.

b<openssl dhparam>, openssl dsa, openssl gendsa, openssl dsaparam, openssl genrsa and openssl rsa have been modified to use PKEY APIs. openssl genrsa and openssl rsa now write PKCS #8 keys by default.

🌸 Default settings 🌸

"SHA256" is now the default digest for TS query used by openssl ts.

💀 Deprecated apps 💀

openssl rsautl is deprecated, use openssl pkeyutl instead. openssl dhparam, openssl dsa, openssl gendsa, openssl dsaparam, openssl genrsa, openssl rsa, openssl genrsa and openssl rsa are now in maintenance mode and no new features will be added to them. (Yes, genrsa and rsa are listed twice — iconic duplication, no cap 🙈.)

🔥 TLS Changes 🔥

  • ✨ TLS 1.3 FFDHE key exchange support added — This uses DH safe prime named groups.
  • ✨ Support for fully "pluggable" TLSv1.3 groups. — This means that providers may supply their own group implementations (using either the "key exchange" or the "key encapsulation" methods) which will automatically be detected and used by libssl.
  • ✨ SSL and SSL_CTX options are now 64 bit instead of 32 bit. — The signatures of the functions to get and set options on SSL and SSL_CTX objects changed from "unsigned long" to uint64_t type. This may require source code changes. For example it is no longer possible to use the SSL_OP_ macro values in preprocessor "#if" conditions. However it is still possible to test whether these macros are defined or not. See SSL_CTX_get_options(3), SSL_CTX_set_options(3), SSL_get_options(3) and SSL_set_options(3).
  • ✨ SSL_set1_host() and SSL_add1_host() Changes — These functions now take IP literal addresses as well as actual hostnames.
  • ✨ Added SSL option SSL_OP_CLEANSE_PLAINTEXT — If the option is set, openssl cleanses (zeroizes) plaintext bytes from internal buffers after delivering them to the application. Note, the application is still responsible for cleansing other copies (e.g.: data received by SSL_read(3)).
  • ✨ Client-initiated renegotiation is disabled by default. — To allow it, use the -client_renegotiation option, the SSL_OP_ALLOW_CLIENT_RENEGOTIATION flag, or the "ClientRenegotiation" config parameter as appropriate.
  • ✨ Secure renegotiation is now required by default for TLS connections — Support for RFC 5746 secure renegotiation is now required by default for SSL or TLS connections to succeed. Applications that require the ability to connect to legacy peers will need to explicitly set SSL_OP_LEGACY_SERVER_CONNECT. Accordingly, SSL_OP_LEGACY_SERVER_CONNECT is no longer set as part of SSL_OP_ALL.
  • ✨ Combining the Configure options no-ec and no-dh no longer disables TLSv1.3 — Typically if OpenSSL has no EC or DH algorithms then it cannot support connections with TLSv1.3. However OpenSSL now supports "pluggable" groups through providers. Therefore third party providers may supply group implementations even where there are no built-in ones. Attempting to create TLS connections in such a build without also disabling TLSv1.3 at run time or using third party provider groups may result in handshake failures. TLSv1.3 can be disabled at compile time using the "no-tls1_3" Configure option.
  • ✨ SSL_CTX_set_ciphersuites() and SSL_set_ciphersuites() changes. — The methods now ignore unknown ciphers.
  • ✨ Security callback change. — The security callback, which can be customised by application code, supports the security operation SSL_SECOP_TMP_DH. This is defined to take an EVP_PKEY in the "other" parameter. In most places this is what is passed. All these places occur server side. However there was one client side call of this security operation and it passed a DH object instead. This is incorrect according to the definition of SSL_SECOP_TMP_DH, and is inconsistent with all of the other locations. Therefore this client side call has been changed to pass an EVP_PKEY instead.
  • ✨ New SSL option SSL_OP_IGNORE_UNEXPECTED_EOF — The SSL option SSL_OP_IGNORE_UNEXPECTED_EOF is introduced. If that option is set, an unexpected EOF is ignored, it pretends a close notify was received instead and so the returned error becomes SSL_ERROR_ZERO_RETURN.
  • ✨ The security strength of SHA1 and MD5 based signatures in TLS has been reduced. — This results in SSL 3, TLS 1.0, TLS 1.1 and DTLS 1.0 no longer working at the default security level of 1 and instead requires security level 0. The security level can be changed either using the cipher string with @SECLEVEL, or calling SSL_CTX_set_security_level(3). This also means that where the signature algorithms extension is missing from a ClientHello then the handshake will fail in TLS 1.2 at security level 1. This is because, although this extension is optional, failing to provide one means that OpenSSL will fallback to a default set of signature algorithms. This default set requires the availability of SHA1.
  • ✨ X509 certificates signed using SHA1 are no longer allowed at security level 1 and above. — In TLS/SSL the default security level is 1. It can be set either using the cipher string with @SECLEVEL, or calling SSL_CTX_set_security_level(3). If the leaf certificate is signed with SHA-1, a call to SSL_CTX_use_certificate(3) will fail if the security level is not lowered first. Outside TLS/SSL, the default security level is -1 (effectively 0). It can be set using X509_VERIFY_PARAM_set_auth_level(3) or using the -auth_level options of the commands.

🌈 SEE ALSO 🌈

fips_module(7) — that's it, just the one, bestie 🫶

📜 HISTORY 📜

The migration guide was created for OpenSSL 3.0. (A classic, iconic, periodt 💅.)

Copyright 2021-2025 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

This page is from OSSL-GUIDE-MIGRATION(7ossl) version 3.5.6, dated 2026-04-07. Byeee 💖✨

📦 where this page comes from