OPENSSL-PKEYUTL(1ossl)

📦
version 3.5.9 · 8 versions
, in alpine 3.23, alpine 3.24

OPENSSL-PKEYUTL(1ossl) ✦ OpenSSL ✦ the asymmetric key command — buckle up bestie, we're going low-level 💅

🌸 NAME 🌸

openssl-pkeyutl — asymmetric key command. That's the whole vibe: one command for poking asymmetric keys directly, and yes, the manual page is literally called OPENSSL-PKEYUTL(1ossl) 😌

✨ SYNOPSIS ✨

openssl pkeyutl [-help] [-in file] [-rawin] [-digest algorithm] [-out
file] [-secret file] [-sigfile file] [-inkey filename|uri] [-keyform
DER|PEM|P12|ENGINE] [-passin arg] [-pubin] [-certin] [-rev] [-sign]
[-verify] [-verifyrecover] [-encrypt] [-decrypt] [-derive] [-peerkey
file] [-peerform DER|PEM|P12|ENGINE] [-encap] [-decap] [-kdf algorithm]
[-kdflen length] [-kemop mode] [-pkeyopt opt:value] [-pkeyopt_passin
opt[:passarg]] [-hexdump] [-asn1parse] [-engine id] [-engine_impl]
[-rand files] [-writerand file] [-provider name] [-provider-path path]
[-provparam [name:]key=value] [-propquery propq] [-config configfile]

💖 DESCRIPTION 💖

Okay so this command does low-level operations on asymmetric keys — public or private, whichever — using any supported algorithm. It's giving "I know exactly what I'm doing with this key" energy.

By default, the signing operation is assumed, and that's the -sign option, bestie. So if you don't tell it otherwise, it's signing. Periodt.

🎀 OPTIONS 🎀

  • -help — Print out a usage message. Tiny helpful angel behavior 🫶
  • -in filename — This specifies the input filename to read data from, or standard input if this option is not specified. No filename? It's reading from stdin, iykyk.
  • -rawin — This indicates that the signature or verification input data is raw data, which is not hashed by any message digest algorithm. Except with EdDSA, the user can specify a digest algorithm by using the -digest option. For signature algorithms like RSA, DSA and ECDSA, the default digest algorithm is SHA256. For SM2, it is SM3.

This option can only be used with -sign and -verify. For EdDSA (the Ed25519 and Ed448 algorithms) this option is implied since OpenSSL 3.5, and required in earlier versions.

The -digest option implies -rawin since OpenSSL 3.5. Slay, but keep track of your version bestie 💀

  • -digest algorithm — This option can only be used with -sign and -verify. It specifies the digest algorithm that is used to hash the input data before signing or verifying it with the input key. This option could be omitted if the signature algorithm does not require preprocessing the input through a pluggable hash function before signing (for instance, EdDSA). If this option is omitted but the signature algorithm requires one and the -rawin option is given, a default value will be used (see -rawin for details). If this option is present, then the -rawin option is implied since OpenSSL 3.5, and required in earlier versions.

At this time, HashEdDSA (the ph or "prehash" variant of EdDSA) is not supported, so the -digest option cannot be used with EdDSA. Not me finding the one EdDSA exception 😭

  • -out filename — Specifies the output filename to write to, or standard output by default. Standard output is lowkey the default main character here.
  • -secret filename — Specifies the shared-secret output filename for when performing encapsulation via the -encap option or decapsulation via the -decap option. The -encap option also produces a separate (public) ciphertext output which is by default written to standard output, but being binary non-text data, is typically also redirected to a file selected via the -out option. Binary data said "I'm not text, bestie" 💀
  • -sigfile file — Signature file, required and allowed for -verify operations only. No sneaking it into other ops, okay?
  • -inkey filename|uri — The input key. By default it should be a private key. Respect the default or specify your own lore.
  • -keyform DER|PEM|P12|ENGINE — The key format; unspecified by default. See openssl-format-options(1) for details. Format crisis? Solved.
  • -passin arg — The input key password source. For more information about the format of arg see openssl-passphrase-options(1). Password lore lives over there.
  • -pubin — By default a private key is read from the key input. With this option a public key is read instead. If the input contains no public key but a private key, its public part is used. The public part said "I'm right here" ✨
  • -certin — The input is a certificate containing a public key. Certificate-coded behavior.
  • -rev — Reverse the order of the input buffer. This is useful for some libraries (such as CryptoAPI) which represent the buffer in little-endian format. This cannot be used in conjunction with -rawin. Little-endian besties, this one's for you, but do not pair it with -rawin.
  • -sign — Sign the input data and output the signed result. This requires a private key. Using a message digest operation along with this is recommended, when applicable, see the -rawin and -digest options for details. Otherwise, the input data given with the -in option is assumed to already be a digest, but this may then require an additional -pkeyopt "digest:"md in some cases (e.g., RSA with the default PKCS#1 padding mode). Even for other algorithms like ECDSA, where the additional -pkeyopt option does not affect signature output, it is recommended, as it enables checking that the input length is consistent with the intended digest. Very "trust but verify your digest length" energy 👑
  • -verify — Verify the input data against the signature given with the -sigfile option and indicate if the verification succeeded or failed. The input data given with the -in option is assumed to be a hash value unless the -rawin option is specified or implied. With raw data, when a digest algorithm is applicable, though it may be inferred from the signature or take a default value, it should also be specified. Don't leave your digest algorithm guessing, bestie 🫶
  • -verifyrecover — Verify the given signature and output the recovered data (signature payload). For example, in case of RSA PKCS#1 the recovered data is the EMSA-PKCS-v1_5 DER encoding of the digest algorithm OID and value as specified in RFC8017 Section 9.2 https://datatracker.ietf.org/doc/html/rfc8017#section-9.2.

Note that here the input given with the -in option is not a signature input (as with the -sign and -verify options) but a signature output value, typically produced using the -sign option.

This option is available only for use with RSA keys. RSA only, no cap 🧢

  • -encrypt — Encrypt the input data using a public key. Public key doing public key things.
  • -decrypt — Decrypt the input data using a private key. Private key doing private key things.
  • -derive — Derive a shared secret using own private (EC)DH key and peer key. Shared secret? We love a collaborative moment 💜
  • -peerkey file — File containing the peer public or private (EC)DH key to use with the key derivation (agreement) operation. Its type must match the type of the own private key given with -inkey. Matching types only, this is not a "close enough" situation.
  • -peerform DER|PEM|P12|ENGINE — The peer key format; unspecified by default. See openssl-format-options(1) for details. Peer key format check: handled ✨
  • -encap — Use a Key Encapsulation Mechanism (KEM) to encapsulate a shared-secret to a peer's public key. The encapsulated result (or ciphertext, non-text binary data) is written to standard output by default, or else to the file specified with -out. The -secret option must also be provided to specify the output file for the derived shared-secret value generated in the encapsulation process. Encapsulation is supported with a number of public key algorithms, currently: ML-KEM, X25519, X448, and EC. The ECX and EC algorithms use the RFC9180 https://www.rfc-editor.org/rfc/rfc9180 DHKEM construction. Encapsulation is also supported with RSA keys via the RSASVE construction.

At the API level, encapsulation and decapsulation are also supported for a few hybrid ECDHE (no DHKEM) plus ML-KEM algorithms, but these are intended primarily for use with TLS and should not be used standalone. There are in any case no standard public and private key formats for the hybrid algorithms, so it is not possible to provide the required key material. So like... don't try it standalone, bestie 🚫

  • -decap — Decode an encapsulated secret, with the use of a -private key, to derive the same shared-secret as that obtained when the secret was encapsulated to the corresponding public key. The encapsulated secret is by default read from the standard input, or else from the file specified with -in. The derived shared-secret is written to the file specified with the -secret option, which must also be provided. Decapsulation is supported with a number of public key algorithms, currently: ML-KEM, X25519, X448, and EC. The ECX and EC algorithms use the RFC9180 https://www.rfc-editor.org/rfc/rfc9180 DHKEM construction. Decapsulation is also supported with RSA keys via the RSASVE construction. Reverse encapsulation, but make it cryptographic 💅
  • -kemop mode — This option is used with the -encap/-decap commands and specifies the KEM mode specific for the key algorithm when there is no default way to encapsulate and decapsulate shared secrets with the chosen key type. All the supported algorithms presently support only their default mode, and this option, though available, is not required. So it's giving "available but not obligatory" 😌
  • -kdf algorithm — Use key derivation function algorithm. The supported algorithms are at present TLS1-PRF and HKDF. Note: additional parameters and the KDF output length will normally have to be set for this to work. See EVP_PKEY_CTX_set_hkdf_md(3) and EVP_PKEY_CTX_set_tls1_prf_md(3) for the supported string parameters of each algorithm. KDF lore is real and it has requirements, okay?
  • -kdflen length — Set the output length for KDF. Length matters, bestie.
  • -pkeyopt opt:value — Public key options specified as opt:value. See NOTES below for more details. Yes, NOTES is literally below — we're getting there 💖
  • -pkeyopt_passin opt[:passarg] — Allows reading a public key option opt from stdin or a password source. If only opt is specified, the user will be prompted to enter a password on stdin. Alternatively, passarg can be specified which can be any value supported by openssl-passphrase-options(1). Password source flex, but make it public-key-option-specific.
  • -hexdump — hex dump the output data. Sometimes you just gotta look at the bytes, no cap.
  • -asn1parse — Parse the ASN.1 output data to check its DER encoding and print any errors. When combined with the -verifyrecover option, this may be useful in case an ASN.1 DER-encoded structure had been signed directly (without hashing it) and when checking a signature in PKCS#1 v1.5 format, which has a DER encoding. ASN.1 girlies rise 🌸
  • -engine id — See "Engine Options" in openssl(1). This option is deprecated. Deprecated means deprecated, bestie — noted and flagged.
  • -engine_impl — When used with the -engine option, it specifies to also use engine id for crypto operations. Engine-ception, but only with -engine.
  • -rand files — See "Random State Options" in openssl(1) for details. Random state lore lives over there.
  • -writerand file — See "Random State Options" in openssl(1) for details. Same random state lore, different flag.
  • -provider name — See "Provider Options" in openssl(1), provider(7), and property(7). Provider behavior, slay.
  • -provider-path path — See "Provider Options" in openssl(1), provider(7), and property(7). Provider path behavior, also slay.
  • -provparam [name:]key=value — See "Provider Options" in openssl(1), provider(7), and property(7). Provider parameter behavior, yes queen.
  • -propquery propq — See "Provider Options" in openssl(1), provider(7), and property(7). Property query, iconic.
  • -config configfile — See "Configuration Option" in openssl(1). Config file lore, unlocked.

📝 NOTES 💅

okay so bestie, listen — the ops and options you actually get depend on the key algorithm and on which implementation of it you're running. The OpenSSL ones are the ones listed below, so don't come for me if your provider is built different 💖

Unless the page says otherwise, -pkeyopt supports the "digest:"alg argument for every public-key type — that's the digest in use for signing and verification. The value alg should be a digest name like the ones EVP_get_digestbyname() knows, for example sha256. Important: this value does not hash your input data for you. It's used (by some algorithms) to sanity-check the lengths of data you pass in, and to build the structures that make up the signature (e.g. DigestInfo in RSASSA PKCS#1 v1.5 signatures).

So fr fr: if you set the -pkeyopt "digest" argument to sha256, then your signature or verification input should be the 32 bytes long binary value of the SHA256 hash function output. Not the text, not the file — the raw 32 bytes 🫶

Unless -rawin is used or implied, this command does not hash the input data — it just yeets your data straight into the signature algorithm as-is. And depending on the key type, signature type and padding mode, the max sensible input length differs:

  • With RSA the signed data cannot be longer than the key modulus.
  • With ECDSA and DSA the data should not be longer than the field size — otherwise it gets silently truncated to the field size 😭 (yes, silently, rude).
  • In any event, the input size must not be larger than the largest supported digest output size EVP_MAX_MD_SIZE, which currently is 64 bytes.

🔐 RSA ALGORITHM

The RSA algorithm generally supports the encrypt, decrypt, sign, verify and verifyrecover operations. But — some padding modes only support a subset of those. The following additional pkeyopt values are supported:

  • rsa_padding_mode:mode — sets the RSA padding mode. Acceptable values for mode are pkcs1 for PKCS#1 padding, none for no padding, oaep for OAEP mode, x931 for X9.31 mode and pss for PSS.
    • For pkcs1: if the message digest is not set, then the supplied data is signed or verified directly instead of using a DigestInfo structure. If a digest is set, then the DigestInfo structure is used and its length must correspond to the digest type.
    • Note: for pkcs1 padding, as a protection against the Bleichenbacher attack, the decryption will not fail in case of padding check failures. Use none and manually inspect the decrypted message to verify whether the decrypted value has correct PKCS#1 v1.5 padding. 👀
    • For oaep mode only encryption and decryption is supported.
    • For x931, if the digest type is set it is used to format the block data; otherwise the first byte is used to specify the X9.31 digest ID. Sign, verify and verifyrecover are can be performed in this mode.
    • For pss mode only sign and verify are supported, and the digest type must be specified.
  • rsa_pss_saltlen:len — for pss mode only, this option specifies the salt length. Three special values are supported: digest sets the salt length to the digest length, max sets the salt length to the maximum permissible value. When verifying, auto causes the salt length to be automatically determined based on the PSS block structure ✨
  • rsa_mgf1_md:digest — for PSS and OAEP padding, sets the MGF1 digest. If the MGF1 digest is not explicitly set in PSS mode, then the signing digest is used.
  • rsa_oaep_md:digest — sets the digest used for the OAEP hash function. If not explicitly set, then SHA1 is used.
  • rsa_pkcs1_implicit_rejection:flag — disables (when set to 0) or enables (when set to 1) the use of implicit rejection with PKCS#1 v1.5 decryption. When enabled (the default), as a protection against Bleichenbacher attack, the library will generate a deterministic random plaintext that it will return to the caller in case of padding check failure. When disabled, it's the callers' responsibility to handle the returned errors in a side-channel free manner. Main character responsibility, honestly.

🔑 RSA-PSS ALGORITHM

RSA-PSS is basically RSA but on a leash — it's a restricted version of the RSA algorithm which only supports the sign and verify operations with PSS padding. The following additional -pkeyopt values are supported:

  • rsa_padding_mode:mode, rsa_pss_saltlen:len, rsa_mgf1_md:digest — these have the same meaning as in the RSA algorithm, with some additional restrictions. The padding mode can only be set to pss, which is the default value.
    • If the key has parameter restrictions, then the digest, MGF1 digest and salt length are set to the values specified in the parameters. The digest and MG cannot be changed, and the salt length cannot be set to a value less than the minimum restriction. 🎀

✍️ DSA ALGORITHM

The DSA algorithm supports signing and verification operations only. Currently there are no additional -pkeyopt options other than digest. The SHA256 digest is assumed by default. slay, simple.

🤝 DH ALGORITHM

The DH algorithm only supports the derivation operation, and there are no additional -pkeyopt options. that's it, that's the whole section 💀

🌸 EC ALGORITHM

The EC algorithm supports sign, verify and derive operations. The sign and verify operations use ECDSA and derive uses ECDH. SHA256 is assumed by default for the -pkeyopt digest option 🦋

🦋 X25519 AND X448 ALGORITHMS

The X25519 and X448 algorithms support key derivation only. Currently there are no additional options. lowkey iconic for knowing exactly what it is 💅

🧚 SLH-DSA ALGORITHMS

The SLH-DSA algorithms (SLH-DSA-SHA2-128s, SLH-DSA-SHA2-128f, SLH-DSA-SHA2-192s, SLH-DSA-SHA2-192f, SLH-DSA-SHA2-256s, SLH-DSA-SHA2-256f) are post-quantum signature algorithms 👑 When using SLH-DSA with pkeyutl, the following options are available:

  • -sign — sign the input data using an SLH-DSA private key. For example:
$ openssl pkeyutl -sign -in file.txt -inkey slhdsa.pem -out sig
  • -verify — verify the signature using an SLH-DSA public key. For example:
$ openssl pkeyutl -verify -in file.txt -inkey slhdsa.pem -sigfile sig

See EVP_PKEY-SLH-DSA(7) and EVP_SIGNATURE-SLH-DSA(7) for additional details about the SLH-DSA algorithm and its implementation 💜

👑 ML-DSA-44, ML-DSA-65 AND ML-DSA-87 ALGORITHMS

The ML-DSA algorithms are post-quantum signature algorithms that support signing and verification of "raw" messages. No preliminary hashing is performed. When using ML-DSA with pkeyutl, the following options are available:

  • -sign — sign the input data using an ML-DSA private key. For example:
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig
  • -verify — verify the signature using an ML-DSA public key. For example:
$ openssl pkeyutl -verify -in file.txt -inkey mldsa65.pem -sigfile sig
  • -pkeyopt opt:value — additional options for ML-DSA signing and verification:
    • message-encoding:value — specifies the message encoding mode used for signing. This controls how the input message is processed before signing. Valid values are described in EVP_SIGNATURE-ML-DSA(7). For example:
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt message-encoding:1
  • test-entropy:value — specifies a test entropy value for deterministic signing. For example:
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt test-entropy:abcdefghijklmnopqrstuvwxyz012345
  • hextest-entropy:value — specifies a test entropy value in hex format. For example:
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt hextest-entropy:000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
  • deterministic:value — enables deterministic signing. For example:
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt deterministic:1
  • mu:value — specifies the mu parameter. For example:
$ echo -n "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef" >file.txt
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt mu:1
  • context-string:string — specifies a context string for both signing and verification operations. The context string must be the same for verification to succeed. For example:
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt context-string:mycontext
$ openssl pkeyutl -verify -in file.txt -inkey mldsa65.pem -sigfile sig -pkeyopt context-string:mycontext
  • hexcontext-string:string — specifies a context string in hex format, allowing binary control values. For example:
$ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt hexcontext-string:6d79636f6e74657874

The signing operation supports a deterministic:bool option, with bool set to 1 if a deterministic signature is to be generated with a fixed all zero random input. By default, or if the bool is 0, a random entropy value is used. A deterministic result can also be obtained by specifying an explicit entropy value via the hextest-entropy:value parameter. > Deterministic ML-DSA signing should only be used in tests. Bestie I'm serious, tests only 🙈

See EVP_SIGNATURE-ML-DSA(7) for additional details about the ML-DSA algorithms and their implementation ✨

💜 ML-KEM-512, ML-KEM-768 AND ML-KEM-1024 ALGORITHMS

The ML-KEM algorithms support encapsulation and decapsulation only. The encapsulation operation supports a hexikme:entropy option, with entropy the 64 hexadecimal digit encoding of a 32-byte value. > This should only be used in tests — known or leaked values of the option may compromise the generated shared secret 😭🔒

See EVP_KEM-ML-KEM(7) for additional detail.

⭐ ED25519 AND ED448 ALGORITHMS

These algorithms only support signing and verifying. OpenSSL only implements the "pure" variants of these algorithms, so raw data can be passed directly to them without hashing them first. OpenSSL only supports "oneshot" operation with these algorithms — which means the entire file to be signed/verified must be read into memory before processing it. Signing or verifying very large files should be avoided 🙈 Additionally the size of the file must be known for this to work. If the size of the file cannot be determined (for example if the input is stdin) then the sign or verify operation will fail 💀

🌸 SM2 🌸

So SM2 is that girl who does everything — sign, verify, encrypt and decrypt, all of it, no cap. ✨

But for the sign and verify operations specifically, SM2 needs a Distinguishing ID string handed to it. It's like a little name tag 🎀 and here's the -pkeyopt values you can slide it:

  • distid:string — sets the ID string used in SM2 sign or verify operations. And bestie, listen: when you're verifying an SM2 signature, the ID string has to be the same one used when signing the data. Otherwise the verification will fail. 💀 Same string or it's over.
  • hexdistid:hex_string — same energy, sets the ID string used in SM2 sign or verify operations, and again, while verifying an SM2 signature the ID string must be the same one used when signing the data, otherwise the verification will fail. The difference? The ID string you pass with this option should be a valid hexadecimal value. 🔢

🧪 EXAMPLES 🧪

Okay this is the fun part, actual recipes, let's gooo 🎀

Sign some data using a private key:

openssl pkeyutl -sign -in file -inkey key.pem -out sig

Recover the signed data (e.g. if an RSA key is used):

openssl pkeyutl -verifyrecover -in sig -inkey key.pem

Verify the signature (e.g. a DSA key):

openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem

Sign data using a message digest value (this is currently only valid for RSA):

openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256
Bestie note: that digest: trick is currently only valid for RSA. Don't try it elsewhere, she will not cooperate. 🙈

Derive a shared secret value:

openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret

Hexdump 48 bytes of TLS1 PRF using digest SHA256 and shared secret and seed consisting of the single byte 0xFF:

openssl pkeyutl -kdf TLS1-PRF -kdflen 48 -pkeyopt md:SHA256 \
   -pkeyopt hexsecret:ff -pkeyopt hexseed:ff -hexdump

Derive a key using scrypt where the password is read from command line:

openssl pkeyutl -kdf scrypt -kdflen 16 -pkeyopt_passin pass \
   -pkeyopt hexsalt:aabbcc -pkeyopt N:16384 -pkeyopt r:8 -pkeyopt p:1

Derive using the same algorithm, but read key from environment variable MYPASS:

openssl pkeyutl -kdf scrypt -kdflen 16 -pkeyopt_passin pass:env:MYPASS \
   -pkeyopt hexsalt:aabbcc -pkeyopt N:16384 -pkeyopt r:8 -pkeyopt p:1

Sign some data using an SM2(7) private key and a specific ID:

openssl pkeyutl -sign -in file -inkey sm2.key -out sig -rawin -digest sm3 \
   -pkeyopt distid:someid

Verify some data using an SM2(7) certificate and a specific ID:

openssl pkeyutl -verify -certin -in file -inkey sm2.cert -sigfile sig \
   -rawin -digest sm3 -pkeyopt distid:someid

Decrypt some data using a private key with OAEP padding using SHA256:

openssl pkeyutl -decrypt -in file -inkey key.pem -out secret \
   -pkeyopt rsa_padding_mode:oaep -pkeyopt rsa_oaep_md:sha256

Create an ML-DSA key pair and sign data with a specific context string:

  $ openssl genpkey -algorithm ML-DSA-65 -out mldsa65.pem
  $ openssl pkeyutl -sign -in file.txt -inkey mldsa65.pem -out sig -pkeyopt context-string:example

Verify a signature using ML-DSA with the same context string:

  $ openssl pkeyutl -verify -in file.txt -inkey mldsa65.pem -sigfile sig -pkeyopt context-string:example

Generate an ML-KEM key pair and use it for encapsulation:

  $ openssl genpkey -algorithm ML-KEM-768 -out mlkem768.pem
  $ openssl pkey -in mlkem768.pem -pubout -out mlkem768_pub.pem
  $ openssl pkeyutl -encap -inkey mlkem768_pub.pem -pubin -out ciphertext -secret shared_secret.bin

Decapsulate a shared secret using an ML-KEM private key:

  $ openssl pkeyutl -decap -inkey mlkem768.pem -in ciphertext -secret decapsulated_secret.bin

Create an SLH-DSA key pair and sign data:

  $ openssl genpkey -algorithm SLH-DSA-SHA2-128s -out slh-dsa.pem
  $ openssl pkeyutl -sign -in file.txt -inkey slh-dsa.pem -out sig

Verify a signature using SLH-DSA:

  $ openssl pkeyutl -verify -in file.txt -inkey slh-dsa.pem -sigfile sig

Slay. Every single one of those is a whole vibe. 💅✨

👀 SEE ALSO 👀

Go read these next, they're all linked in the group chat:

🕰️ HISTORY 🕰️

Lore drop, pay attention 📖✨

Since OpenSSL 3.5, the -digest option implies -rawin. The -rawin option is no longer required when signing or verifying with a key type that does not support a prehash digest, such as Ed25519, Ed448, ML-DSA, or SLH-DSA. For these key types, -digest is not supported. 🚫

Also since OpenSSL 3.5, the -kemop option is no longer required for any of the supported algorithms, the only supported mode is now the default. ✅

The -engine option was deprecated in OpenSSL 3.0. 🪦 (RIP, she's retired.)

Copyright 2006-2026 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>.

okay that's the whole page, you made it to the end, I'm so proud of you 🫶💖 This little gem is from OpenSSL 3.5.9, dated 2026-09-29, and it lives at the page address OPENSSL-PKEYUTL(1ossl) — go forth and pkeyutl responsibly, bestie. 🌈👑✨

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