crypto(3)
💖 crypto — Erlang Module Definition 💖
okay bestie, sit down, hydrate, because the crypto module is THAT girl. it's the Erlang module definition for everyone's favorite box of cryptographic functions, and she does not play. let's get into it 💅
✨ NAME ✨
crypto — Crypto Functions 🎀
🌸 DESCRIPTION 🌸
This module provides a set of cryptographic functions. that's it, that's the vibe, but also there is SO much under the hood. look at her range 🦋
- Hash functions —
- SHA1, SHA2 — Secure Hash Standard (FIPS PUB180-4) ✨
- SHA3 — SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions (FIPS PUB 202) 💜
- BLAKE2 — BLAKE2 — fast secure hashing 🔥
- SM3 — The SM3 Hash Function (GM/T 0004-2012) 🌸
- MD5 — The MD5 Message Digest Algorithm (RFC 1321) 💀
- MD4 — The MD4 Message Digest Algorithm (RFC 1320) 💀
- MACs — Message Authentication Codes —
Symmetric Ciphers 👑
- DES, 3DES and AES — Block Cipher Techniques (NIST)
- Blowfish — Fast Software Encryption, Cambridge Security Workshop Proceedings (December 1993), Springer-Verlag, 1994, pp. 191-204.
- Chacha20 — ChaCha20 and Poly1305 for IETF Protocols (RFC 7539)
- Chacha20_poly1305 — ChaCha20 and Poly1305 for IETF Protocols (RFC 7539)
- SM4 — The SM4 Block Cipher Algorithm
- Modes —
- ECB, CBC, CFB, OFB and CTR — Recommendation for Block Cipher Modes of Operation: Methods and Techniques (NIST SP 800-38A) 🌈
- GCM — Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC (NIST SP 800-38D) 🌈
- CCM — Recommendation for Block Cipher Modes of Operation: The CCM Mode for Authentication and Confidentiality (NIST SP 800-38C) 🌈
- Asymmetric Ciphers — Public Key Techniques —
NOTE: The actual supported algorithms and features depends on their availability in the actual libcrypto used. See the crypto (App) about dependencies. Enabling FIPS mode will also disable algorithms and features. 🚨
The CRYPTO User's Guide has more information on FIPS, Engines and Algorithm Details like key lengths. 📚✨
🫶 Exceptions 🫶
💅 Atoms — the older style
The exception error:badarg signifies that one or more arguments are of wrong data type, or are otherwise badly formed. not me passing the wrong type 😭
The exception error:notsup signifies that the algorithm is known but is not supported by current underlying libcrypto or explicitly disabled when building that. so like, she exists in theory but she's not available rn 🙈
For a list of supported algorithms, see supports(ciphers).
💅 3-tuples — the new style
The exception is:
error:{Tag, C_FileInfo, Description}
Tag = badarg | notsup | error
C_FileInfo = term() % Usually only useful for the OTP maintainer
Description = string() % Clear text, sometimes only useful for the OTP maintainerThe exception tags are:
badarg— Signifies that one or more arguments are of wrong data type or are otherwise badly formed. 🫠notsup— Signifies that the algorithm is known but is not supported by current underlying libcrypto or explicitly disabled when building that one. 🙃error— An error condition that should not occur, for example a memory allocation failed or the underlying cryptolib returned an error code, for example"Can't initialize context, step 1". Those text usually needs searching the C-code to be understood. 💀 (no seriously, you're gonna be digging through C for that one)
Usually there are more information in the call stack about which argument caused the exception and what the values where. 👀
To catch the exception, use for example:
try crypto:crypto_init(Ciph, Key, IV, true)
catch
error:{Tag, _C_FileInfo, Description} ->
do_something(......)
.....
end🌈 DATA TYPES 🌈
okay bestie this is the big one, the type definitions, the whole cast of characters. buckle up 💖
blake2() :: blake2b | blake2s.cipher() :: cipher_no_iv() | cipher_iv() | cipher_aead().cipher_aead() ::
aes_128_ccm | aes_192_ccm | aes_256_ccm | aes_ccm |
aes_128_gcm | aes_192_gcm | aes_256_gcm | aes_gcm | sm4_gcm |
sm4_ccm | chacha20_poly1305.Ciphers known by the CRYPTO application. 👑
Note that this list might be reduced if the underlying libcrypto does not support all of them.
cipher_iv() ::
aes_128_cbc | aes_192_cbc | aes_256_cbc | aes_cbc |
aes_128_ofb | aes_192_ofb | aes_256_ofb | aes_128_cfb128 |
aes_192_cfb128 | aes_256_cfb128 | aes_cfb128 | aes_128_cfb8 |
aes_192_cfb8 | aes_256_cfb8 | aes_cfb8 | aes_128_ctr |
aes_192_ctr | aes_256_ctr | aes_ctr | sm4_cbc | sm4_ofb |
sm4_cfb | sm4_ctr | blowfish_cbc | blowfish_cfb64 |
blowfish_ofb64 | chacha20 | des_ede3_cbc | des_ede3_cfb |
des_cbc | des_cfb | rc2_cbc.cipher_no_iv() ::
aes_128_ecb | aes_192_ecb | aes_256_ecb | aes_ecb |
blowfish_ecb | des_ecb | sm4_ecb | rc4.cmac_cipher_algorithm() ::
aes_128_cbc | aes_192_cbc | aes_256_cbc | aes_cbc |
blowfish_cbc | des_cbc | des_ede3_cbc | rc2_cbc.compatibility_only_hash() :: md5 | md4.The compatibility_only_hash/0 algorithms are recommended only for compatibility with existing applications. 🫶 (translation: only use these if something old is forcing your hand, bestie, do not pick them for new stuff)
crypto_integer() :: binary() | integer().crypto_opt() :: {encrypt, boolean()} | {padding, padding()}.Selects encryption ({encrypt,true}) or decryption ({encrypt,false}). 🔐
crypto_opts() :: boolean() | [crypto_opt()].-opaque crypto_state()cryptolib_padding() :: none | pkcs_padding.The cryptolib_padding are paddings that may be present in the underlying cryptolib linked to the Erlang/OTP crypto app.
For OpenSSL, see the OpenSSL documentation. and find EVP_CIPHER_CTX_set_padding() in cryptolib for your linked version. 📖
dh_params() :: [key_integer()].
dh_params() = [P, G] | [P, G, MaxPrivateKeyBitLength]dh_private() :: key_integer().dh_public() :: key_integer().dss_digest_type() :: sha1() | sha2().dss_private() :: [key_integer()].
dss_public() = [P, Q, G, Y]
Where P, Q and G are the dss parameters and Y is the public key.
dss_private() = [P, Q, G, X]
Where P, Q and G are the dss parameters and X is the private key.dss_public() :: [key_integer()].ec_basis() ::
{tpbasis, K :: non_neg_integer()} |
{ppbasis,
K1 :: non_neg_integer(),
K2 :: non_neg_integer(),
K3 :: non_neg_integer()} |
onbasis.Curve definition details. 📐
ec_characteristic_two_field() ::
{characteristic_two_field,
M :: integer(),
Basis :: ec_basis()}.ec_curve() ::
{A :: binary(), B :: binary(), Seed :: none | binary()}.Parametric curve definition. ✨
ec_explicit_curve() ::
{Field :: ec_field(),
Curve :: ec_curve(),
BasePoint :: binary(),
Order :: binary(),
CoFactor :: none | binary()}.ec_field() :: ec_prime_field() | ec_characteristic_two_field().ec_named_curve() ::
brainpoolP160r1 | brainpoolP160t1 | brainpoolP192r1 |
brainpoolP192t1 | brainpoolP224r1 | brainpoolP224t1 |
brainpoolP256r1 | brainpoolP256t1 | brainpoolP320r1 |
brainpoolP320t1 | brainpoolP384r1 | brainpoolP384t1 |
brainpoolP512r1 | brainpoolP512t1 | c2pnb163v1 | c2pnb163v2 |
c2pnb163v3 | c2pnb176v1 | c2pnb208w1 | c2pnb272w1 |
c2pnb304w1 | c2pnb368w1 | c2tnb191v1 | c2tnb191v2 |
c2tnb191v3 | c2tnb239v1 | c2tnb239v2 | c2tnb239v3 |
c2tnb359v1 | c2tnb431r1 | ipsec3 | ipsec4 | prime192v1 |
prime192v2 | prime192v3 | prime239v1 | prime239v2 |
prime239v3 | prime256v1 | secp112r1 | secp112r2 | secp128r1 |
secp128r2 | secp160k1 | secp160r1 | secp160r2 | secp192k1 |
secp192r1 | secp224k1 | secp224r1 | secp256k1 | secp256r1 |
secp384r1 | secp521r1 | sect113r1 | sect113r2 | sect131r1 |
sect131r2 | sect163k1 | sect163r1 | sect163r2 | sect193r1 |
sect193r2 | sect233k1 | sect233r1 | sect239k1 | sect283k1 |
sect283r1 | sect409k1 | sect409r1 | sect571k1 | sect571r1 |
wtls1 | wtls10 | wtls11 | wtls12 | wtls3 | wtls4 | wtls5 |
wtls6 | wtls7 | wtls8 | wtls9.(she has RANGE okay, that whole list is one type definition, iconic 👑)
ec_prime_field() :: {prime_field, Prime :: integer()}.ecdh_params() ::
ec_named_curve() | edwards_curve_dh() | ec_explicit_curve().ecdh_private() :: key_integer().ecdh_public() :: key_integer().ecdsa_digest_type() :: sha1() | sha2().ecdsa_params() :: ec_named_curve() | ec_explicit_curve().ecdsa_private() :: key_integer().ecdsa_public() :: key_integer().eddsa_params() :: edwards_curve_ed().eddsa_private() :: key_integer().eddsa_public() :: key_integer().edwards_curve_dh() :: x25519 | x448.edwards_curve_ed() :: ed25519 | ed448.Note that some curves are disabled if FIPS is enabled. heads up bestie 💅
engine_cmnd() :: {unicode:chardata(), unicode:chardata()}.Pre and Post commands for engine_load/3 and /4. 🛠️
engine_key_ref() ::
#{engine := engine_ref(),
key_id := key_id(),
password => password(),
term() => term()}.engine_method_type() ::
engine_method_rsa | engine_method_dsa | engine_method_dh |
engine_method_rand | engine_method_ecdh |
engine_method_ecdsa | engine_method_ciphers |
engine_method_digests | engine_method_store |
engine_method_pkey_meths | engine_method_pkey_asn1_meths |
engine_method_ec.engine_ref() :: term().The result of a call to engine_load/3. ✨
hash_algorithm() ::
sha1() |
sha2() |
sha3() |
sha3_xof() |
blake2() |
ripemd160 | sm3 |
compatibility_only_hash().-opaque hash_state()hash_xof_algorithm() :: sha3_xof().hmac_hash_algorithm() ::
sha1() | sha2() | sha3() | sm3 | compatibility_only_hash().kem() :: mlkem512 | mlkem768 | mlkem1024.Key encapsulation mechanisms. 🔐
key_id() :: string() | binary().okay bestie that's part 1 wrapped, but we are SO not done — more parts are coming, don't go anywhere 💖✨
key()— Identifies the key to be used.</p> The format depends on the loaded engine. It is passed to theENGINE_load_(private|public)_keyfunctions inlibcrypto.key_integer() :: integer() | binary()— Alwaysbinary/0when used as return value.-opaque mac_state()— Contexts with an internal state that should not be manipulated 🙅♀️ — just pass them between function calls, bestie. Hands off the internals.mldsa() :: mldsa44 | mldsa65 | mldsa87mldsa_private() :: {seed | expandedkey, binary()}mldsa_public() :: binary()otp_padding() :: zero | random— Erlang/OTP adds either padding of zeroes or padding with random bytes.padding() :: cryptolib_padding() | otp_padding()— This option handles padding in the last block. If it's not set, no padding is done and any bytes sitting in the last unfilled block get silently discarded 💀 (yes, gone, no warning, nothing).password() :: string() | binary()— The password of the key stored in an engine.pk_encrypt_decrypt_algs() :: rsa— Algorithms for public key encrypt/decrypt. Only RSA is supported.pk_encrypt_decrypt_opts() :: [rsa_opt()] | rsa_compat_opts()
pk_sign_verify_algs() ::
rsa | dss | ecdsa | eddsa | mldsa() | slh_dsa().Algorithms for sign and verify.
pk_sign_verify_opts() :: [rsa_sign_verify_opt()]rand_cache_state() :: binary()rand_plugin_aes_state() :: dynamic()
rand_plugin_prng1_init_state() ::
{cipher_iv(), binary(), binary(), binary()}.rand_plugin_prng1_state() ::
rand_plugin_prng1_init_state() |
maybe_improper_list(binary(), {crypto_state(), binary()}).rand_plugin_state() :: no_statersa_compat_opts() :: [{rsa_pad, rsa_padding()}] | rsa_padding()— Those option forms are kept only for compatibility and should not be used in new code. 🫶 legacy vibes only, pls don't build anything new on these.rsa_digest_type() :: sha1() | sha2() | md5 | ripemd160
rsa_opt() ::
{rsa_padding, rsa_padding()} |
{signature_md, atom()} |
{rsa_mgf1_md, sha} |
{rsa_oaep_label, binary()} |
{rsa_oaep_md, sha}.rsa_padding() ::
rsa_pkcs1_padding | rsa_pkcs1_oaep_padding |
rsa_x931_padding | rsa_no_padding.Options for public key encrypt/decrypt. Only RSA is supported.
⚠️ WARNING: The RSA options are experimental. The exact set of options and there syntax may be changed without prior notice. No cap, this can shift under you.
rsa_params() ::
{ModulusSizeInBits :: integer(),
PublicExponent :: key_integer()}. rsa_public() = [E, N]
rsa_private() = [E, N, D] | [E, N, D, P1, P2, E1, E2, C]Where E is the public exponent, N is public modulus and D is the private exponent. The longer key format contains redundant information that will make the calculation faster. P1 and P2 are first and second prime factors. E1 and E2 are first and second exponents. C is the CRT coefficient. The terminology is taken from RFC 3447.
rsa_private() :: [key_integer()]rsa_public() :: [key_integer()]
rsa_sign_verify_opt() ::
{rsa_padding, rsa_sign_verify_padding()} |
{rsa_pss_saltlen, integer()} |
{rsa_mgf1_md, sha2()}.rsa_sign_verify_padding() ::
rsa_pkcs1_padding | rsa_pkcs1_pss_padding | rsa_x931_padding |
rsa_no_padding.Options for sign and verify.
⚠️ WARNING: The RSA options are experimental. The exact set of options and there syntax may be changed without prior notice. Still experimental, still could change, still not your safe little rock.
sha1() :: sha
sha2() ::
sha224 | sha256 | sha384 | sha512 | sha512_224 | sha512_256.sha3() :: sha3_224 | sha3_256 | sha3_384 | sha3_512sha3_xof() :: shake128 | shake256
slh_dsa() ::
slh_dsa_shake_128s | slh_dsa_shake_128f | slh_dsa_sha2_128s |
slh_dsa_sha2_128f | slh_dsa_shake_192s | slh_dsa_shake_192f |
slh_dsa_sha2_192s | slh_dsa_sha2_192f | slh_dsa_shake_256s |
slh_dsa_shake_256f | slh_dsa_sha2_256s | slh_dsa_sha2_256f.slh_dsa_private() :: binary()slh_dsa_public() :: binary()
srp_comp_params() ::
{user, srp_user_comp_params()} |
{host, srp_host_comp_params()}.srp_gen_params() ::
{user, srp_user_gen_params()} | {host, srp_host_gen_params()}.srp_host_comp_params() :: [binary() | atom()]
Where Verifier is v, Generator is g and Prime is N, DerivedKey is X, and Scrambler is u (optional will be generated if not provided) from SRP design Version = '3' | '6' | '6a'
srp_host_gen_params() :: [binary() | atom() | list()]srp_private() :: key_integer()
srp_public() = key_integer()Where is A or B from SRP design
srp_private() = key_integer()Where is a or b from SRP design
srp_public() :: key_integer()srp_user_comp_params() :: [binary() | atom()]srp_user_gen_params() :: [binary() | atom() | list()]
✨ FUNCTIONS ✨
okay bestie this is the good part, the actual functions, let's GO 🏃♀️💨
🌸 bytes_to_integer(binary()) -> integer()
bytes_to_integer(binary()) -> integer().Convert binary representation, of an integer, to an Erlang integer. That's it, that's the whole job. ✨
🦋 cipher_info(Type) -> Result
cipher_info(Type) -> Result
when
Type :: cipher(),
Result ::
#{key_length := integer(),
iv_length := integer(),
block_size := integer(),
mode := CipherModes,
type := undefined | integer(),
prop_aead := boolean()},
CipherModes ::
undefined | cbc_mode | ccm_mode |
cfb_mode | ctr_mode | ecb_mode | gcm_mode |
ige_mode | ocb_mode | ofb_mode |
wrap_mode | xts_mode.Get information about a cipher algorithm. 📋
Returns a map with information about block size, key length, IV length, aead support and possibly other properties of the cipher algorithm in question.
NOTE: The ciphersaes_cbc,aes_cfb8,aes_cfb128,aes_ctr,aes_ecb,aes_gcmandaes_ccmhas no keylength in theTypeas opposed to for exampleaes_128_ctr. They adapt to the length of the key provided in the encrypt and decrypt function. Therefore it is impossible to return a valid keylength in the map. Always use aTypewith an explicit key length, like fr, always, don't make it guess 🫠
For a list of supported cipher algorithms, see supports(ciphers).
💜 compute_key(Type, OthersPublicKey, MyPrivateKey, Params) -> SharedSecret
compute_key(Type, OthersPublicKey, MyPrivateKey, Params) ->
SharedSecret
when
Type :: dh | ecdh | eddh | srp,
SharedSecret :: binary(),
OthersPublicKey ::
dh_public() | ecdh_public() | srp_public(),
MyPrivateKey ::
dh_private() |
ecdh_private() |
{srp_public(), srp_private()},
Params ::
dh_params() |
ecdh_params() |
srp_comp_params().Compute the shared secret from the private key and the other party's public key. 🤝 it's giving secure handshake
See also public_key:compute_key/2.
Uses the 3-tuple style for error handling. (iykyk)
🧚 crypto_final(State) -> FinalResult
crypto_final(State) -> FinalResult
when
State :: crypto_state(),
FinalResult :: binary().Finalize a streaming encryptions or decryptions operation and delivers the final bytes of the final block. 🏁
The data returned from this function may be empty if no padding was enabled in crypto_init/3 or crypto_init/4. (yes bestie, empty binary is a valid answer, don't panic 🙈)
Uses the 3-tuple style for error handling.
🌈 crypto_get_data(State) -> Result
crypto_get_data(State) -> Result
when State :: crypto_state(), Result :: map().Return information about a crypto_state/0. 🔍
The information returned is a map, which currently contains at least:
size— The number of bytes encrypted or decrypted so far.padding_size— After a call tocrypto_final/1it contains the number of bytes padded. Otherwise0.padding_type— The type of the padding as provided in the call tocrypto_init/3orcrypto_init/4.encrypt— Istrueif encryption is performed. It isfalseotherwise.
Uses the 3-tuple style for error handling.
🎀 crypto_init(Cipher, Key, FlagOrOptions) -> State
crypto_init(Cipher, Key, FlagOrOptions) -> State
when
Cipher :: cipher_no_iv(),
Key :: iodata(),
FlagOrOptions :: crypto_opts() | boolean(),
State :: crypto_state().Initialize the state for a streaming encryption or decryption operation. 🚀
Equivalent to the call crypto_init(Cipher, Key, <<>>, FlagOrOptions). It is intended for ciphers without an IV (nounce). no IV squad, this one's for you
Uses the 3-tuple style for error handling.
💅 crypto_init(Cipher, Key, IV, FlagOrOptions) -> State
crypto_init(Cipher, Key, IV, FlagOrOptions) -> State
when
Cipher :: cipher_iv(),
Key :: iodata(),
IV :: iodata(),
FlagOrOptions :: crypto_opts(),
State :: crypto_state().Initialize the state for a streaming encryptions or decryptions operation. ✨
The returned state should be used as argument to crypto_update/2 and crypto_final/1 to do the actual encryption or decryption. pass it around like a baton, bestie 🏃♀️
If IV = <<>>, no IV is used. This is intended for ciphers without an IV (nounce). See crypto_init/3.
For encryption, set the FlagOrOptions to true or [{encrypt,true}]. For decryption, set it to false or [{encrypt,false}].
Padding could be enabled with the option {padding,Padding}. The cryptolib_padding enables pkcs_padding or no padding (none). The paddings zero or random fills the last part of the last block with zeroes or random bytes. If the last block is already full, nothing is added.
In decryption, the cryptolib_padding removes such padding, if present. The otp_padding is not removed — it has to be done elsewhere. so don't come crying to decryption about your leftover otp padding, that's a you problem 💀
okay so bestie, listen: if padding is {padding,none} or you just don't specify it, and the total data from all the subsequent crypto_updates doesn't fill the last block all the way, that last chunk of data is gone. Like, lost. 💀 In the {padding,none} case you'll get an error. But if padding is just not specified at all? The bytes of that unfilled block get silently discarded. No warning, no nothing. 🫠
The actual padding magic happens in crypto_final/1.
Wanna know blocksizes? Call cipher_info/1.
This uses the 3-tuple style for error handling.
See examples in the User's Guide. 📖
crypto_one_time(Cipher, Key, Data, FlagOrOptions) -> Result
when
Cipher :: cipher_no_iv(),
Key :: iodata(),
Data :: iodata(),
FlagOrOptions :: crypto_opts() | boolean(),
Result :: binary().Do a complete encrypt or decrypt of the full text. ✨
It's like crypto_one_time/5 but for ciphers that don't have IVs.
Uses the 3-tuple style for error handling.
See examples in the User's Guide.
crypto_one_time(Cipher, Key, IV, Data, FlagOrOptions) -> Result
when
Cipher :: cipher_iv(),
Key :: iodata(),
IV :: iodata(),
Data :: iodata(),
FlagOrOptions :: crypto_opts() | boolean(),
Result :: binary().Do a complete encrypt or decrypt of the full text. 🔐
Data is literally the text you wanna encrypt or decrypt.
For encryption, set FlagOrOptions to true. For decryption, set it to false. For setting other options, see crypto_init/4.
Uses the 3-tuple style for error handling.
See examples in the User's Guide.
crypto_one_time_aead(State, IV, InText, AAD) -> Result
when
State :: crypto_state(),
IV :: iodata(),
InText :: iodata(),
AAD :: iodata(),
Result :: EncryptResult | DecryptResult,
EncryptResult :: binary(),
DecryptResult :: binary() | error.Do a complete encrypt or decrypt with an AEAD cipher of the full text. 🦋
Similar to crypto_one_time_aead/7 but uses the handle from crypto_one_time_aead_init/4.
When you're encrypting, it appends the tag of the specified TagLength to the end of the encrypted data. When you're decrypting, it strips the tag from the end of InText and verifies it. 🔍
crypto_one_time_aead(Cipher, Key, IV, InText, AAD, EncFlag :: true) -> Result
when
Cipher :: cipher_aead(),
Key :: iodata(),
IV :: iodata(),
InText :: iodata(),
AAD :: iodata(),
Result :: EncryptResult,
EncryptResult :: {OutCryptoText, OutTag},
OutCryptoText :: binary(),
OutTag :: binary().Do a complete encrypt with an AEAD cipher of the full text with the default tag length. 🔥
Equivalent to crypto_one_time_aead(Cipher, Key, IV, InText, AAD, TagLength, true) where TagLength is the default tag length for the given Cipher.
crypto_one_time_aead(Cipher, Key, IV, InText, AAD, TagOrTagLength, EncFlag) -> Result
when
Cipher :: cipher_aead(),
Key :: iodata(),
IV :: iodata(),
InText :: iodata(),
AAD :: iodata(),
TagOrTagLength :: EncryptTagLength | DecryptTag,
EncryptTagLength :: non_neg_integer(),
DecryptTag :: iodata(),
EncFlag :: boolean(),
Result :: EncryptResult | DecryptResult,
EncryptResult :: {OutCryptoText, OutTag},
DecryptResult :: OutPlainText | error,
OutCryptoText :: binary(),
OutTag :: binary(),
OutPlainText :: binary().Do a complete encrypt or decrypt with an AEAD cipher of the full text. 💖
For encryption: set EncryptFlag to true and set TagOrTagLength to the wanted size (in bytes) of the tag, aka the tag length. If you want the default length, you can just use the crypto_one_time_aead/6 form. Easy peasy.
For decryption: set EncryptFlag to false and put the tag you wanna check in the TagOrTagLength argument.
WARNING: The length of the tag at decryption is not checked by the function. It's the caller's responsibility to make sure the length of the tag matches the length of the tag used when the data was encrypted. Otherwise the decryption might succeed if the given tag only matches the start of the proper tag. 🚨 So like, double-check that, bestie.
Additional Authentication Data (AAD) is plaintext data that will not be encrypted, but will be covered by authenticity protection. It should be provided through the AAD argument, but can be an empty binary as well (<<>>) if you don't need it. In that case, a plain AE (Authenticated Encryption) is performed instead of AEAD (Authenticated Encryption with Associated Data). This function only supports ciphers that can be used both with and without AAD.
Uses the 3-tuple style for error handling.
See examples in the User's Guide. ✨
crypto_one_time_aead_init(Cipher, Key, TagLength, EncFlag) -> Result
when
Cipher :: cipher_aead(),
Key :: iodata(),
TagLength :: non_neg_integer(),
EncFlag :: boolean(),
Result :: crypto_state().Initializes AEAD cipher. 🎀
Similar to crypto_one_time_aead/7 but only does the initialization part. Returns a handle that you can use with crypto_one_time_aead/4 several times. Reuse, reuse, reuse. 💅
crypto_update(State, Data) -> Result
when
State :: crypto_state(),
Data :: iodata(),
Result :: binary().Add data to a streaming encryption or decryption operation. 🌊
If the part is less than a number of full blocks, only the full blocks (possibly none) are encrypted or decrypted and the remaining bytes are saved to the next crypto_update operation. The State should be created with crypto_init/3 or crypto_init/4.
Uses the 3-tuple style for error handling.
See examples in the User's Guide.
decapsulate_key(Type, MyPrivKey, EncapSecret) -> Secret
when
Type :: kem(),
MyPrivKey :: binary(),
EncapSecret :: binary(),
Secret :: binary().Regenerate shared secret from encapsulated secret and private key. 🔑
Returns a shared secret for encryption/decryption by the local party.
Supported encapsulation methods can be obtained with supports(kems). iykyk.
ec_curve(CurveName) -> ExplicitCurve
when
CurveName :: ec_named_curve(),
ExplicitCurve :: ec_explicit_curve().Return the defining parameters of an elliptic curve. 🌈
ec_curves() -> [EllipticCurve]
when
EllipticCurve :: ec_named_curve() |
edwards_curve_dh() |
edwards_curve_ed().Return all supported named elliptic curves. 👑
enable_fips_mode(Enable) -> Result
when
Enable :: boolean(),
Result :: boolean().Deprecated: crypto:enable_fips_mode/1 is deprecated; use config parameter fips_mode. 🚫 So like, maybe don't use this unless you have to?
Enable or disable FIPS mode.
Argument Enable should be true to enable and false to disable FIPS mode. Returns true if the operation was successful or false otherwise.
Note that to enable FIPS mode successfully, OTP must be built with the configure option --enable-fips, and the underlying libcrypto must also support FIPS.
See also info_fips/0.
encapsulate_key(Type, OthersPublicKey) -> {Secret, EncapSecret}
when
Type :: kem(),
OthersPublicKey :: binary(),
Secret :: binary(),
EncapSecret :: binary().Generate encapsulated shared secret from the other party's public key. 🤝
Returns both a shared secret for encryption/decryption by the local party and an encapsulated format of the same secret to be safely sent to the other party. With its private key, the other party can decapsulate the received secret (with decapsulate_key/3 for example) to regenerate the same shared secret.
Supported encapsulation methods can be obtained with supports(kems).
engine_add(Engine) -> Result
when
Engine :: engine_ref(),
Result :: ok | {error, Reason :: term()}.Add the engine to OpenSSL's internal list. ⚙️
The function raises a error:badarg if the parameters are in wrong format. It may also raise the exception error:notsup in case there is no engine support in the underlying OpenSSL implementation. So like, be careful. 💀
engine_by_id(EngineId) -> Result
when
EngineId :: unicode:chardata(),
Result ::
{ok, Engine :: engine_ref()} |
{error, Reason :: term()}.Get a reference to an already loaded engine using its EngineId, bestie. An error tuple is returned if the engine cannot be unloaded. 💅
Heads up: the function raises aerror:badargif the parameter is in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
See also the chapter Engine Load in the User's Guide. 🫶
engine_ctrl_cmd_string(Engine, CmdName, CmdArg) -> Result
when
Engine :: term(),
CmdName :: unicode:chardata(),
CmdArg :: unicode:chardata(),
Result ::
ok | {error, Reason :: term()}.Send ctrl commands to an OpenSSL engine, no cap. This function is the same as calling engine_ctrl_cmd_string/4 with Optional set to false.
Watch out: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
engine_ctrl_cmd_string(Engine, CmdName, CmdArg, Optional) ->
Result
when
Engine :: term(),
CmdName :: unicode:chardata(),
CmdArg :: unicode:chardata(),
Optional :: boolean(),
Result ::
ok | {error, Reason :: term()}.Send ctrl commands to an OpenSSL engine. Optional is a boolean argument that can relax the semantics of the function. If set to true it will only return failure if the ENGINE supported the given command name but failed while executing it; if the ENGINE does not support the command name it will simply return success without doing anything. In this case we assume the user is only supplying commands specific to the given ENGINE, so we set this to false. ✨
Not me having to say it again: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
engine_get_all_methods() -> Result
when Result :: [engine_method_type()].Return a list of all possible engine methods. It’s giving “here’s the whole menu,” bestie. 📋
May raise exception error:notsup in case there is no engine support in the underlying OpenSSL implementation.
See also the chapter Engine Load in the User's Guide. 🦋
engine_get_id(Engine) -> EngineId
when
Engine :: engine_ref(),
EngineId :: unicode:chardata().Return the ID for the engine, or an empty binary if there is no id set. Simple as that. 💖
Careful: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
engine_get_name(Engine) -> EngineName
when
Engine :: engine_ref(),
EngineName :: unicode:chardata().Return the name (eg a description) for the engine, or an empty binary if there is no name set. It’s the engine’s little name tag. 🏷️
Careful: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
engine_list() -> Result
when Result :: [EngineId :: unicode:chardata()].List the id's of all engines in OpenSSL's internal list. Yes, the whole group chat. 💬
It may also raise the exception error:notsup in case there is no engine support in the underlying OpenSSL implementation.
See also the chapter Engine Load in the User's Guide.
May raise exception error:notsup in case engine functionality is not supported by the underlying OpenSSL implementation.
engine_load(EngineId, PreCmds, PostCmds) -> Result
when
EngineId :: unicode:chardata(),
PreCmds :: [engine_cmnd()],
PostCmds :: [engine_cmnd()],
Result ::
{ok, Engine :: engine_ref()} |
{error, Reason :: term()}.Load an OpenSSL engine. Loads the OpenSSL engine given by EngineId if it is available and intialize it. Returns ok and an engine handle, or if the engine cannot be loaded an error tuple is returned. 🔥
Heads up: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
See also the chapter Engine Load in the User's Guide. 🌸
engine_register(Engine, EngineMethods) -> Result
when
Engine :: engine_ref(),
EngineMethods :: [engine_method_type()],
Result :: ok | {error, Reason :: term()}.Register engine to handle some type of methods, for example engine_method_digests. It’s like giving the engine a job in the group project. 💅
Heads up: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
engine_remove(Engine) -> Result
when
Engine :: engine_ref(),
Result :: ok | {error, Reason :: term()}.Remove the engine from OpenSSL's internal list. Bye bestie, you’re off the roster. 👋
Heads up: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
engine_unload(Engine) -> Result
when
Engine :: engine_ref(),
Result :: ok | {error, Reason :: term()}.Unload an OpenSSL engine. Unloads the OpenSSL engine given by Engine. An error tuple is returned if the engine cannot be unloaded. 🧚
Heads up: the function raises aerror:badargif the parameter is in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
See also the chapter Engine Load in the User's Guide. 💜
engine_unregister(Engine, EngineMethods) -> Result
when
Engine :: engine_ref(),
EngineMethods :: [engine_method_type()],
Result :: ok | {error, Reason :: term()}.Unregister engine so it does not handle some type of methods. Taking away its little tasks, periodt.
Heads up: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
ensure_engine_loaded(EngineId, LibPath) -> Result
when
EngineId :: unicode:chardata(),
LibPath :: unicode:chardata(),
Result ::
{ok, Engine :: engine_ref()} |
{error, Reason :: term()}.Load a dynamic engine if not already done. Loada the engine given by EngineId and the path to the dynamic library implementing the engine. An error tuple is returned if the engine cannot be loaded. 🎀
This function differs from the normal engine_load in the sense that it also add the engine id to OpenSSL's internal engine list. The difference between the first call and the following is that the first loads the engine with the dynamical engine and the following calls fetch it from the OpenSSL's engine list. All references that is returned are equal. 🫶
Use engine_unload/1 function to remove the references. But remember that engine_unload/1 just removes the references to the engine and not the tag in OpenSSL's engine list. That has to be done with the engine_remove/1 function when needed (just called once, from any of the references you got). 🧠
Heads up: the function raises aerror:badargif the parameters are in wrong format. It may also raise the exceptionerror:notsupin case there is no engine support in the underlying OpenSSL implementation.
See also the chapter Engine Load in the User's Guide. 🌈
exor(iodata(), iodata()) -> binary().Perform bit-wise XOR (exclusive or) on the data supplied. The two byte sequences must be of equal length. No cap, that’s literally the whole vibe. ⭐
🫶 generate_key(Type, Params, PrivKeyIn) -> {PublicKey, PrivKeyOut} 🫶
generate_key(Type, Params, PrivKeyIn) -> {PublicKey, PrivKeyOut}
when
Type ::
dh | ecdh | eddh | eddsa | rsa |
mldsa() |
mlkem512 | mlkem768 | mlkem1024 | srp |
slh_dsa(),
PublicKey ::
dh_public() |
ecdh_public() |
rsa_public() |
srp_public(),
PrivKeyIn ::
undefined |
dh_private() |
ecdh_private() |
rsa_private() |
{srp_public(), srp_private()},
PrivKeyOut ::
dh_private() |
ecdh_private() |
rsa_private() |
{srp_public(), srp_private()},
Params ::
dh_params() |
ecdh_params() |
eddsa_params() |
rsa_params() |
srp_comp_params() |
[].okay so this one is literally the glow-up station bestie 👑 — it generates a public key. That's the whole vibe. New key, who dis.
Also peep public_key:generate_key/1 if you wanna see the cousin function doing similar things.
And yes, it uses the 3-tuple style for error handling — so you get your {ok, ...} / {error, ...} energy instead of a dramatic crash. 💅
NOTE: if the linked version of cryptolib is OpenSSL 3.0 - and theTypeisdh(diffie-hellman), - and the parameterP(indh_params/0) is one of the MODP groups (see RFC 3526), - and the optionalMaxPrivateKeyBitLengthparameter (indh_params/0) is present, then the optional key length parameter must be at least224,256,302,352and400for group sizes of2048,3072,4096,6144and8192, respectively. no shortcuts, the math said what it said 😭
🦋 hash(Type, Data) -> Digest 🦋
hash(Type, Data) -> Digest
when
Type :: hash_algorithm(),
Data :: iodata(),
Digest :: binary().Compute a message digest, periodt. Argument Type is the digest type and argument Data is the full message — like, the whole thing, not a lil piece.
Uses the 3-tuple style for error handling. ✨
🎀 hash_equals(BinA, BinB) -> Result 🎀
hash_equals(BinA, BinB) -> Result
when
BinA :: binary(),
BinB :: binary(),
Result :: boolean().Compare two binaries in constant time, such as results of HMAC computations. This is the timing-attack-safe bestie, she does not leak anything, she does not gossip 🫢
Returns true if the binaries are identical, false if they are of the same length but not identical. The function raises an error:badarg exception if the binaries are of different size — so don't hand her mismatched lengths, she will simply refuse. 💀
🌸 hash_final(State) -> Digest 🌸
hash_final(State) -> Digest
when State :: hash_state(), Digest :: binary().Finalize a streaming hash calculation — this is the grand finale of your digest saga 🎬
Argument State as returned from the last call to hash_update. The size of Digest is determined by the type of hash function used to generate it. iykyk.
Uses the 3-tuple style for error handling.
🌈 hash_info(Type) -> Result 🌈
hash_info(Type) -> Result
when
Type :: hash_algorithm(),
Result ::
#{size := integer(),
block_size := integer(),
type := integer()}.Get information about a hash algorithm. Returns a map with information about block_size, size and possibly other properties of the hash algorithm in question. Lowkey a whole vibe check for your hash.
For a list of supported hash algorithms, see supports(hashs). 📋
💜 hash_init(Type) -> State 💜
hash_init(Type) -> State
when Type :: hash_algorithm(), State :: hash_state().Initialize the state for a streaming hash digest calculation. Argument Type determines which digest to use. The returned state should be used as argument to hash_update/2 — don't lose her, she's the main character of this operation 🎀
Uses the 3-tuple style for error handling.
⭐ hash_update(State, Data) -> NewState ⭐
hash_update(State, Data) -> NewState
when
State :: hash_state(),
NewState :: hash_state(),
Data :: iodata().Add data to a streaming digest calculation. Update the digest using the given Data of any length — she does not care about size, she is flexible like that.
Argument State must have been generated by hash_init or a previous call to this function.
Returns NewState that must be passed into the next call to hash_update/2 or hash_final/1. It's a chain, bestie — hand her off, don't drop her. 🔗
Uses the 3-tuple style for error handling.
🧚 hash_xof(Type, Data, Length) -> Digest 🧚
hash_xof(Type, Data, Length) -> Digest
when
Type :: hash_xof_algorithm(),
Data :: iodata(),
Length :: non_neg_integer(),
Digest :: binary().Compute a message digest for an xof_algorithm. Argument Type is the type of digest, Data is the full text and Length is the digest length in bits — bits, not bytes, do not get got. 👀
Uses the 3-tuple style for error handling.
May raise exception error:notsup in case the chosen Type is not supported by the underlying libcrypto implementation.
👑 info() 👑
info() ->
#{compile_type := normal | debug | valgrind | asan,
cryptolib_version_compiled := string() | undefined,
cryptolib_version_linked := string(),
link_type := dynamic | static,
otp_crypto_version := string(),
fips_provider_available => boolean(),
fips_provider_buildinfo => string()}.Get information about crypto and the OpenSSL backend. Returns a map with information about the compilation and linking of crypto. It's giving receipts. 🧾
Example:
1> crypto:info().
#{compile_type => normal,
cryptolib_version_compiled => "OpenSSL 3.0.0 7 sep 2021",
cryptolib_version_linked => "OpenSSL 3.0.0 7 sep 2021",
link_type => dynamic,
otp_crypto_version => "5.0.2",
fips_provider_available => true,
fips_provider_buildinfo => "3.0.0"}
2>Heads up: more association types than documented may be present in the map. Some of the associations (like fips) may be absent if not supported. So don't be surprised, she keeps some secrets. 🤫
💅 info_fips() -> not_supported | not_enabled | enabled. 💅
Get information about the operating status of FIPS.
Returns the FIPS operating status of crypto and the underlying libcrypto library. If crypto was built with FIPS support this can be either enabled (when running in FIPS mode) or not_enabled. For other builds this value is always not_supported.
See configuration parameter fips_mode about how to enable FIPS mode.
WARNING: In FIPS mode all non-FIPS compliant algorithms are disabled and raise exceptionerror:notsup. Checksupports(ciphers)that in FIPS mode returns the restricted list of available algorithms. She is strict, she is picky, she is not negotiating 😤
🍓 info_lib() -> [{Name, VerNum, VerStr}] 🍓
info_lib() -> [{Name, VerNum, VerStr}]
when
Name :: binary(),
VerNum :: integer(),
VerStr :: binary().Get the name and version of the libraries used by crypto.
Name is the name of the library. VerNum is the numeric version according to the library's own versioning scheme. VerStr contains a text variant of the version. Three lil facts, one tidy tuple. 💖
> info_lib().
[{<<"OpenSSL">>,269484095,<<"OpenSSL 1.1.0c 10 Nov 2016"">>}]NOTE: from OTP R16 the numeric version represents the version of the OpenSSL header files (openssl/opensslv.h) used when crypto was compiled. The text variant represents the libcrypto library used at runtime. In earlier OTP versions both numeric and text was taken from the library. so like, one is the past and one is the present, they are not the same girl 👯
🔥 mac(Type :: poly1305, Key, Data) -> Mac 🔥
mac(Type :: poly1305, Key, Data) -> Mac
when Key :: iodata(), Data :: iodata(), Mac :: binary().Compute a poly1305 MAC (Message Authentication Code). Same as mac(Type, undefined, Key, Data). It's the lazy-girl shortcut and honestly? iconic. ✨
Uses the 3-tuple style for error handling.
💖 mac(Type, SubType, Key, Data) -> Mac 💖
mac(Type, SubType, Key, Data) -> Mac
when
Type :: hmac | cmac | poly1305,
SubType ::
hmac_hash_algorithm() |
cmac_cipher_algorithm() |
undefined,
Key :: iodata(),
Data :: iodata(),
Mac :: binary().Compute a MAC (Message Authentication Code). Argument Type is the type of MAC and Data is the full message.
SubType depends on the MAC Type:
- For
hmacit is a hash algorithm, see Algorithm Details in the User's Guide. - For
cmacit is a cipher suitable for cmac, see Algorithm Details in the User's Guide. - For
poly1305it should be set toundefinedor themac/2function could be used instead, see Algorithm Details in the User's Guide.
Key is the authentication key with a length according to the Type and SubType. The key length could be found with the hash_info/1 (hmac) for and cipher_info/1 (cmac) functions. For poly1305 the key length is 32 bytes. Note that the cryptographic quality of the key is not checked — she takes your word for it, bestie, so make good choices.
The Mac result will have a default length depending on the Type and SubType. To set a shorter length, use macN/4 or macN/5 instead. The default length is documented in Algorithm Details in the User's Guide.
Uses the 3-tuple style for error handling.
✨ macN(Type :: poly1305, Key, Data, MacLength) -> Mac ✨
macN(Type :: poly1305, Key, Data, MacLength) -> Mac
when
Key :: iodata(),
Data :: iodata(),
Mac :: binary(),
MacLength :: pos_integer().Compute a poly1305 MAC (Message Authentication Code) with a limited length. Snip snip, shorter tag, same energy. ✂️
Same as macN(Type, undefined, Key, Data, MacLength).
Uses the 3-tuple style for error handling.
🌸 macN(Type, SubType, Key, Data, MacLength) -> Mac
macN(Type, SubType, Key, Data, MacLength) -> Mac
when
Type :: hmac | cmac | poly1305,
SubType ::
hmac_hash_algorithm() |
cmac_cipher_algorithm() |
undefined,
Key :: iodata(),
Data :: iodata(),
Mac :: binary(),
MacLength :: pos_integer().ok so this is the MAC function but make it fashionably short 💅 It works exactly like mac/3 and mac/4, except MacLength caps how big the resulting Mac gets — at most MacLength bytes, bestie. But heads up 🫶 if MacLength is bigger than the actual number of bytes the underlying hash spits out, you just get that shorter length instead. No padding, no drama. And the max MacLength? That's documented in Algorithm Details in the User's Guide 📖.
🎀 mac_final(State) -> Mac
mac_final(State) -> Mac when State :: mac_state(), Mac :: binary().Wrap up a streaming MAC operation, bestie ✨
State is whatever the last call to mac_update/2 handed back to you.
The Mac you get out has a default length that depends on the Type and SubType you fed into the mac_init/2,3 call. Wanna shorter one? Use mac_finalN/2 instead 👑 The default length is documented in Algorithm Details in the User's Guide.
Uses the 3-tuple style for error handling.
🦋 mac_finalN(State, MacLength) -> Mac
mac_finalN(State, MacLength) -> Mac
when
State :: mac_state(),
MacLength :: pos_integer(),
Mac :: binary().Same finalize energy, but with a custom length, periodt 💅
State is the state as returned by the last call to mac_update/2.
Mac comes out as a binary with at most MacLength bytes. And again — if MacLength is greater than the actual number of bytes the underlying hash returns, the returned hash has that shorter length instead. The math said no 🍓
The max MacLength is documented in Algorithm Details in the User's Guide.
Uses the 3-tuple style for error handling.
🧚 mac_init(Type :: poly1305, Key) -> State
mac_init(Type :: poly1305, Key) -> State
when Key :: iodata(), State :: mac_state().Set up a state for streaming poly1305 MAC calculation 🌈
Literally the same as mac_init(Type, undefined, Key).
Uses the 3-tuple style for error handling.
💜 mac_init(Type, SubType, Key) -> State
mac_init(Type, SubType, Key) -> State
when
Type :: hmac | cmac | poly1305,
SubType ::
hmac_hash_algorithm() |
cmac_cipher_algorithm() |
undefined,
Key :: iodata(),
State :: mac_state().Initialize the state for streaming MAC calculation, bestie 👑
Type decides which MAC algorithm gets used in the operation. Simple as.
SubType depends on the MAC Type:
- For
hmacit's a hash algorithm — see Algorithm Details in the User's Guide 📖 - For
cmacit's a cipher suitable for cmac — see Algorithm Details in the User's Guide 📖 - For
poly1305it should be set toundefined, or you could just use themac/2function instead — see Algorithm Details in the User's Guide 📖
Key is the authentication key, and its length has to match up with the Type and SubType. You can find that key length with the hash_info/1 function (for hmac) and the cipher_info/1 function (for cmac). For poly1305 the key length is 32 bytes. And ngl, the cryptographic quality of the key is not checked 🙈 not our problem.
The State you get back should be used in one or more subsequent calls to mac_update/2. The MAC value finally gets returned when you call mac_final/1 or mac_finalN/2.
Uses the 3-tuple style for error handling.
See examples in the User's Guide.
⭐ mac_update(State0, Data) -> State
mac_update(State0, Data) -> State
when
Data :: iodata(),
State0 :: mac_state(),
State :: mac_state().Add data into a streaming MAC calculation 🫶
Update the MAC represented by State0 using the given Data, which can be literally any length, no cap.
State0 is the State value you originally got from a MAC init function — that's mac_init/2, mac_init/3, or the last call to mac_update/2. Now here's the tea: the value State0 is returned unchanged by the function, as a reference to a mutated internal state. Which means you can NOT branch off a data stream by reusing old states, bestie 😭 that door is closed.
Uses the 3-tuple style for error handling.
💖 mod_pow(N, P, M) -> Result
mod_pow(N, P, M) -> Result
when
N :: binary() | integer(),
P :: binary() | integer(),
M :: binary() | integer(),
Result :: binary() | error.Compute the function N^P mod M ✨ that's it, that's the function.
🌈 pbkdf2_hmac(Digest, Pass, Salt, Iter, KeyLen) -> Result
pbkdf2_hmac(Digest, Pass, Salt, Iter, KeyLen) -> Result
when
Digest ::
sha | sha224 | sha256 | sha384 | sha512 |
sha512_224 | sha512_256,
Pass :: binary(),
Salt :: binary(),
Iter :: pos_integer(),
KeyLen :: pos_integer(),
Result :: binary().PKCS #5 PBKDF2 (Password-Based Key Derivation Function 2) combined with HMAC 💅 like a little collab.
Uses the 3-tuple style for error handling.
🔥 private_decrypt(Algorithm, CipherText, PrivateKey, Options) -> PlainText
private_decrypt(Algorithm, CipherText, PrivateKey, Options) ->
PlainText
when
Algorithm :: pk_encrypt_decrypt_algs(),
CipherText :: binary(),
PrivateKey ::
rsa_private() | engine_key_ref(),
Options :: pk_encrypt_decrypt_opts(),
PlainText :: binary().Decrypt using a private key 🔐
Decrypts the CipherText — which was encrypted with public_encrypt/4 (or an equivalent function) — using the PrivateKey, and returns the plaintext (message digest). This is a low level signature verification operation, used for instance by older versions of the SSL protocol. See also public_key:decrypt_private/2,3.
Uses the 3-tuple style for error handling.
WARNING 🚨: This is a legacy function, and for security reasons do not use with rsa_pkcs1_padding. fr fr.
👑 private_encrypt(Algorithm, PlainText, PrivateKey, Options) -> CipherText
private_encrypt(Algorithm, PlainText, PrivateKey, Options) ->
CipherText
when
Algorithm :: pk_encrypt_decrypt_algs(),
PlainText :: binary(),
PrivateKey ::
rsa_private() | engine_key_ref(),
Options :: pk_encrypt_decrypt_opts(),
CipherText :: binary().Encrypt using a private key 🔐
Encrypts the PlainText using the PrivateKey and returns the ciphertext. This is a low level signature operation, used for instance by older versions of the SSL protocol. See also public_key:encrypt_private/2,3.
Uses the 3-tuple style for error handling.
Public-key decryption using the private key. See also crypto:private_decrypt/4.
WARNING 🚨: This is a legacy function, and for security reasons do not use withrsa_pkcs1_padding. For digital signatures, usingsign/4together withverify/5is the prefered solution. periodt.
🍓 privkey_to_pubkey(Type, EnginePrivateKeyRef) -> PublicKey
privkey_to_pubkey(Type, EnginePrivateKeyRef) -> PublicKey
when
Type :: rsa | dss,
EnginePrivateKeyRef :: engine_key_ref(),
PublicKey :: rsa_public() | dss_public().Fetch a public key from a private key that's stored in an Engine ✨
The key has to be of the type indicated by the Type parameter, no switching up 🫶
🌸 public_decrypt(Algorithm, CipherText, PublicKey, Options) -> PlainText
public_decrypt(Algorithm, CipherText, PublicKey, Options) ->
PlainText
when
Algorithm :: pk_encrypt_decrypt_algs(),
CipherText :: binary(),
PublicKey :: rsa_public() |
engine_key_ref(),
Options :: pk_encrypt_decrypt_opts(),
PlainText :: binary().Decrypt using a public key 🔓
Decrypts the CipherText — which was encrypted with private_encrypt/4 (or an equivalent function) — using the PublicKey, and returns the plaintext (message digest). This is a low level signature verification operation, used for instance by older versions of the SSL protocol. See also public_key:decrypt_public/2,3.
Uses the 3-tuple style for error handling.
WARNING 🚨: This is a legacy function, and for security reasons do not use withrsa_pkcs1_padding. For digital signatures, usingverify/5together withsign/4is the prefered solution. iykyk 💅
🎀 public_encrypt(Algorithm, PlainText, PublicKey, Options) -> CipherText
public_encrypt(Algorithm, PlainText, PublicKey, Options) ->
CipherText
when
Algorithm :: pk_encrypt_decrypt_algs(),
PlainText :: binary(),
PublicKey :: rsa_public() |
engine_key_ref(),
Options :: pk_encrypt_decrypt_opts(),
CipherText :: binary().Encrypt using a public key 🔓
Encrypts the PlainText (message digest) using the PublicKey and returns the CipherText. This is a low level signature operation, used for instance by older versions of the SSL protocol. See also public_key:encrypt_public/2,3.
Uses the 3-tuple style for error handling.
WARNING 🚨: This is a legacy function, and for security reasons do not use together with rsa_pkcs1_padding. do not, bestie 😭
🦋 rand_seed() -> {rand:alg_handler(crypto), rand_plugin_state()}
rand_seed() -> {rand:alg_handler(crypto), rand_plugin_state()}.Make a generator for rand and save it in the process dictionary ✨
Equivalent to rand_seed_s/0 — but it also saves the returned state object (the generator) in the process dictionary. So basically it's equivalent to rand:seed(rand_seed_s()). two-for-one deal 💅
See rand:seed/1 and rand_seed_s/0.
Example 👇
_ = crypto:rand_seed(),
IntegerValue = rand:uniform(42), % 1 .. 42
FloatValue = rand:uniform(). % [0.0, 1.0)Note 💀 okay so when you're using the process dictionary for cryptographically secure random numbers, you have to make sure that no code called between initializing the generator and between generating numbers accidentally alters the generator state in the process dictionary. Like, none. Zero. The safe approach is to use therandfunctions that do not use the process dictionary but take an explicit state argument instead: the ones suffixed_s. And because of all that? It's ratherrand_seed_s/0that should be used instead of this function. 🫶
💖 rand_seed(binary()) -> ok.
Mixes in the bytes of the given binary into the internal state of OpenSSL's random number generator. 🎲
This calls the RAND_seed function from OpenSSL. Only use this if the system you are running on does not have enough "randomness" built in. Normally this is when strong_rand_bytes/1 or a generator from rand_seed_alg_s/1 raises error:low_entropy. 👑
🎀 rand_seed_alg/1 and friends
rand_seed_alg(Alg :: crypto) ->
{rand:alg_handler(crypto), rand_plugin_state()};
(Alg :: crypto_cache) ->
{rand:alg_handler(crypto_cache), rand_cache_state()};
(ExportState :: {crypto, rand_plugin_state()}) ->
{rand:alg_handler(crypto), rand_plugin_state()};
(ExportState :: {crypto_cache, rand_cache_state()}) ->
{rand:alg_handler(crypto_cache), rand_cache_state()};
(ExportState :: {crypto_aes, rand_plugin_aes_state()}) ->
{rand:alg_handler(crypto_aes), rand_plugin_aes_state()};
(ExportState :: {crypto_prng1, rand_plugin_prng1_init_state()}) ->
{rand:alg_handler(crypto_prng1), rand_plugin_prng1_init_state()};
(State) -> State
when
State ::
{rand:alg_handler(crypto), rand_plugin_state()} |
{rand:alg_handler(crypto_cache), rand_cache_state()} |
{rand:alg_handler(crypto_aes), rand_plugin_aes_state()} |
{rand:alg_handler(crypto_prng1), rand_plugin_prng1_state()}.Create a generator for rand with the specified algorithm, and save it in the process dictionary. ✨
Equivalent to rand_seed_alg_s/1 but also saves the returned state object (generator) in the process dictionary. That is, equivalent to rand:seed(rand_seed_alg_s(Alg)).
See rand:seed/1 and rand_seed_alg_s/1. And pls note the warning about the usage of the process dictionary in rand_seed/0 — it still applies, bestie. 🫶
Example
_ = crypto:rand_seed_alg(crypto_cache),
IntegerValue = rand:uniform(42), % 1 .. 42
FloatValue = rand:uniform(). % [0.0, 1.0)🌸 rand_seed_alg(Alg :: crypto_aes, Seed :: iodata()) and the two-arg era
rand_seed_alg(Alg :: crypto_aes, Seed :: iodata()) ->
{rand:alg_handler(crypto_aes), rand_plugin_aes_state()};
(Alg :: crypto_prng1, Seed :: iodata()) ->
{rand:alg_handler(crypto_prng1), rand_plugin_prng1_state()}.Create and seed a generator for rand with the specified algorithm, and save it in the process dictionary. 🌈
Equivalent to rand_seed_alg_s/2 but also saves the returned state object (generator) in the process dictionary. That is, equivalent to rand:seed(rand_seed_alg_s(Alg, Seed)).
See rand:seed/1 and rand_seed_alg_s/2. Note the warning about the usage of the process dictionary in rand_seed/0. 😭
Example
_ = crypto:rand_seed_alg(crypto_aes, "my seed"),
IntegerValue = rand:uniform(42), % 1 .. 42
FloatValue = rand:uniform(), % [0.0, 1.0)
_ = crypto:rand_seed_alg(crypto_aes, "my seed"),
IntegerValue = rand:uniform(42), % Same values
FloatValue = rand:uniform(). % againLike, same seed → same numbers. That's the whole point, and it ate. 💅
👑 rand_seed_alg_s/1
rand_seed_alg_s(Alg :: crypto) ->
{rand:alg_handler(crypto), rand_plugin_state()};
(Alg :: crypto_cache) ->
{rand:alg_handler(crypto_cache), rand_cache_state()};
(ExportState :: {crypto, rand_plugin_state()}) ->
{rand:alg_handler(crypto), rand_plugin_state()};
(ExportState :: {crypto_cache, rand_cache_state()}) ->
{rand:alg_handler(crypto_cache), rand_cache_state()};
(ExportState :: {crypto_aes, rand_plugin_aes_state()}) ->
{rand:alg_handler(crypto_aes), rand_plugin_aes_state()};
(ExportState :: {crypto_prng1, rand_plugin_prng1_init_state()}) ->
{rand:alg_handler(crypto_prng1), rand_plugin_prng1_init_state()};
(State) -> State
when
State ::
{rand:alg_handler(crypto), rand_plugin_state()} |
{rand:alg_handler(crypto_cache), rand_cache_state()} |
{rand:alg_handler(crypto_aes), rand_plugin_aes_state()} |
{rand:alg_handler(crypto_prng1), rand_plugin_prng1_state()}.Create a generator for rand with the specified algorithm. 🦋
Create a state object (generator) for random number generation, which when used by the rand functions produce cryptographically strong random number.
See rand:seed_s/1 and for example rand:uniform_s/2.
🌟 With Alg = crypto
The created generator uses OpenSSL's BN_rand_range for uniform integers and floats.
The generator also implements generating bytes efficiently with OpenSSL's RAND_bytes, just like strong_rand_bytes/1. See also rand:bytes_s/2. Since OTP 29.0. ✨
Because the OpenSSL library is called for every request, this generator has got a very small generator state, but a large call overhead, so for numbers and small numbers of bytes (about 10), it becomes very slow compared to the default PRNG in the rand module. This is an unfair comparison because a PRNG is not cryptographically strong. Still, for a larger numbers of bytes, (about 1 000 or more) this generator is the fastest. 🔥
This function is equivalent to rand_seed_s/0.
💜 With Alg = crypto_cache
The created generator fetches random data with OpenSSL's RAND_bytes, just like strong_rand_bytes/1, and caches it in the generator's state. Then 56 bit numbers are extracted from the cache, which makes operations in module rand fast on 64 bit machines. 🧚
The generator also implements extracting bytes efficiently. See also rand:bytes_s/2. Since OTP 29.0.
Caching random data improves amortized performance a lot so for numbers it becomes less than a factor 2 slower than the default PRNG in the rand module. For bytes it performs very much like for Alg = crypto above.
Since this generator caches random data it is a bad idea to copy its state in an attempt to fork into multiple generators. The forked generators will produce the same numbers until their caches are empty, which cannot be regarded as cryptographically strong, and is probably never useful. 💀
Example
S0 = crypto:rand_seed_alg_s(crypto_cache),
{IntegerValue, S1} = rand:uniform(42, S0), % 1 .. 42
{FloatValue, S2} = rand:uniform(S1). % [0.0, 1.0)These generators may cause the rand functions using the returned state object to raise the exception error:low_entropy in case the random generator failed due to lack of secure "randomness".
The cache size can be changed from its default value using the crypto app's configuration parameter rand_cache_size.
NOTE: The state returned from this function cannot be used to get a reproducible random sequence as from the other rand functions, since that would not be cryptographically safe. In fact when random data is cached some numbers may get reproduced, but this is unpredictable. The only supported usage is to generate one distinct random sequence. 🎀
🌈 With argument ExportState
For completeness, this function accepts an ExportState from rand:export_seed_s/1 used on one of this module's generators. This function can probably only be useful for algorithm crypto_aes.
For algorithm crypto it is not very useful since the produced numbers are as unpredictable for a new generator as for one re-created with this function.
The same goes for algorithm crypto_cache, but its exported state may contain cached random numbers which might delay having to call OpenSSL the first time, so there is a possible slight performance gain.
For algorithm crypto_aes this function works as described in rand:export_seed_s/1 and rand:seed_s/1.
For algorithm crypto_prng1 this function only works as described in rand:export_seed_s/1 and rand:seed_s/1 on the initial state after creation (seeding). After the first random number has been created, the state contains a crypto_state/0 that does not survive a roundtrip through Erlang's external term format. 🙈
🍓 With argument State
For completeness, this function accepts a State just as rand:seed_s does. Calling this function with a State from one of the algorithms in this module only passes the state through, it is a no-op. 🫶
rand_seed_alg_s(Alg :: crypto_aes, Seed :: iodata()) ->
{rand:alg_handler(crypto_aes),
rand_plugin_aes_state()};
(Alg :: crypto_prng1, Seed :: iodata()) ->
{rand:alg_handler(crypto_prng1),
rand_plugin_prng1_state()}.Okay so you wanna create and seed a generator for rand with a specified algorithm. That's the whole vibe. 💅
What you're actually doing is building a state object (a generator, bestie) that — when the rand functions get their little hands on it — spits out cryptographically unpredictable random numbers, ones you can reproduce by feeding in the exact same Seed again. ✨
Go peek at rand:seed_s/1, and like, rand:uniform_s/2 for an example, and compare it to rand_seed_alg/1 while you're at it.
Heads up: the state objects this function makes have cached data, so they eat way more memory than the generators over in the rand module. Not a surprise, but worth knowing. 🌸
When Alg = crypto_aes 🎀
The Xoroshiro928 generator from the rand module gets used as a counter. Its state gets scrambled through AES-256 to make a 58-bit pseudo random value. This gives you a long period — 2^928 - 1. Iconic.
The results should be statistically completely unpredictable random values, since the scrambling is cryptographically strong and the period is extremely long. But — and this is the part nobody skips, bestie — the generated numbers are not to be regarded as cryptographically strong, because there's no re-keying schedule, and because the sequence just repeats for the same seed.
- If you need cryptographically strong random numbers, use
rand_seed_alg_s/1withAlg =:= cryptoorAlg =:= crypto_cache. - If you need to be able to repeat the sequence, use this function with
Alg =:= crypto_aes(orAlg =:= crypto_prng1, coming right up below ⬇️). - If you don't need the statistical quality of these generators, there are faster generators in the
randmodule. The amortized speed of this one is about 3 times slower than therandmodule's default algorithm.
Example 🍓
1> S0 = crypto:rand_seed_alg_s(crypto_aes, "my seed").
2> %% 1..42
{IntegerValue, S1} = rand:uniform_s(42, S0).
3> %% [0.0, 1.0)
{FloatValue, S2} = rand:uniform_s(S1).
4> {IntegerValue,FloatValue}.
{9,0.7624867055217882}
5> S3 = crypto:rand_seed_alg_s(crypto_aes, "my seed").
6> %% Same values
{IntegerValue, S4} = rand:uniform_s(42, S3).
7> %% again
{FloatValue, S5} = rand:uniform_s(S4).Thanks to the generator it's using, the state object supports the rand:jump/0,1 function with distance 2^512. Slay. 💜
Numbers get generated in batches and cached in the generator's state for speed reasons. You can change the cache size from its default using the crypto app's configuration parameter rand_cache_size.
Generating bytes — see rand:bytes_s/2 — is done from the cached numbers, which limits the performance to about the same as generating numbers. Alg = crypto is faster for that; for larger numbers of bytes it's significantly faster, but it can't be used to reproduce a sequence. Another option is Alg = crypto_prng1, which follows right here. 🦋
When Alg = crypto_prng1 — since OTP 29.0 🎉
The generator it creates uses a stream cipher to encrypt data blocks of zeros, which effectively results in the stream cipher's key stream as binary data. That binary data is cached in the generator's state to get good amortized speed. From the cached data, 58 bit numbers are extracted, so that operations in the rand module stay fast. The cache size can be changed from its default using the crypto app's configuration parameter rand_cache_size. (Yes, same parameter, no cap.)
This generator also implements extracting bytes efficiently through rand:bytes_s/2. 🫶
The key stream from a stream cipher is cryptographically unpredictable, which should give you statistically completely unpredictable random values — but again, these generated numbers are not to be regarded as cryptographically strong, since there's no re-keying schedule, and since the sequence repeats for the same seed.
For generating numbers, this generator is about 2 times slower than the default PRNG in the rand module. For generating bytes it's significantly faster, for any number of bytes. Compared to Alg = crypto, this generator has much less overhead, so for small numbers of bytes it's much faster. Break-even is a bit above the cache size, and over that Alg = crypto is faster — but it can't be used to reproduce a sequence. Balance, bestie. ⭐
Example 💖
1> S0 = crypto:rand_seed_alg_s(crypto_prng1, "my seed").
2> %% 1..42
{IntegerValue, S1} = rand:uniform_s(42, S0).
3> {Bytes, S2} = rand:bytes_s(7, S1).
4> {IntegerValue,Bytes}.
{20,<<52,185,212,38,248,228,127>>}
5> S3 = crypto:rand_seed_alg_s(crypto_prng1, "my seed").
6> %% Same values
{IntegerValue, S4} = rand:uniform_s(42, S3).
7> %% again
{Bytes, S5} = rand:bytes_s(7, S4).The generator's state contains a crypto_state/0 which refers to the same encryption state even when copied, and the generator's state contains cached random data. So it is a bad idea to copy the state in an attempt to fork into multiple generators. 🙈 The forked generators will produce the same numbers until their caches are empty, and then refill their caches with different sections of the keystream. This is probably never useful. (Like, never.)
The created initial state, however, can be copied and exported — as described for rand:export_seed_s/1 and rand:seed_s/1 — since the crypto_state/0 isn't created until the first random value is generated. An exported subsequent generator state cannot be passed intact through Erlang's external term format, and rand_seed_alg_s/1 will fail for an exported state of this generator that is not an initial state. 😭
rand:jump/1 is implemented for this generator, but also only for its initial state. A jump, for this generator, is implemented by incrementing the cipher's IV to create a distinct keystream. This isn't much different from using different seed values, but it avoids a call to the hash function that's used when seeding.
Example 🌈
1> Sa0 = crypto:rand_seed_alg_s(crypto_prng1, "my seed").
2> Sb0 = rand:jump(Sa0).
3> {BytesA, Sa1} = rand:bytes_s(7, Sa0).
4> {BytesB, Sb1} = rand:bytes_s(7, Sb0).
5> BytesA.
<<77,185,41,162,118,82,190>>
6> BytesB.
<<160,61,224,29,177,30,68>>
7> SA0 = crypto:rand_seed_alg_s(crypto_prng1, "my seed").
8> SB0 = rand:jump(SA0).
%% Same values again
9> {BytesA, SA1} = rand:bytes_s(7, SA0).
10> {BytesB, SB1} = rand:bytes_s(7, SB0).Algorithm details 👑
The Seed is hashed with SHA-384 to create a Key and IV for AES-256 that is run in CTR mode over blocks of zero data.
rand_seed_s() ✨
rand_seed_s() -> {rand:alg_handler(crypto), rand_plugin_state()}.Create a generator for rand.
Create a state object (generator) for random number generation which, when used by the rand functions, produces cryptographically strong random numbers (based on OpenSSL's BN_rand_range function). See rand:seed_s/1, and for example rand:uniform_s/2.
This generator also implements generating bytes efficiently (based on OpenSSL's RAND_bytes function). See rand:bytes_s/2 and strong_rand_bytes/1. Since OTP 29.0. 💅
Example 🎀
S0 = crypto:rand_seed_s(),
{RandomInteger, S1} = rand:uniform_s(1000, S0).It may cause the rand functions using this state object to raise the exception error:low_entropy in case the random generator failed due to lack of secure "randomness". 😭
NOTE: The state returned from this function cannot be used to get a reproducible random sequence as from the other rand functions, since that would not be cryptographically safe. The only supported usage is to generate one distinct random sequence. Periodt.
rand_uniform 💀
rand_uniform(crypto_integer(), crypto_integer()) ->
crypto_integer().Deprecated: crypto:rand_uniform/2 is deprecated; use strong_rand_range/1 instead
Generate a random integer number.
The interval is From =< N < To. Uses the crypto library pseudo-random number generator. To must be larger than From.
NOTE: This function is deprecated because it originally used the OpenSSL methodBN_pseudo_rand_rangethat was not cryptographically strong and could not run out of entropy. That behaviour changed in OpenSSL and this function cannot be fixed without making it raiseerror:low_entropy, which is not backwards compatible. Instead, usestrong_rand_range(To - From) + From. Be aware of the possibleerror:low_entropyexception. 👑
sign 📝
sign(Algorithm, DigestType, Msg, Key, Options) -> Signature
when
Algorithm :: pk_sign_verify_algs(),
DigestType ::
rsa_digest_type() |
dss_digest_type() |
ecdsa_digest_type() |
none,
Msg :: iodata() | {digest, iodata()},
Key ::
rsa_private() |
dss_private() |
[ecdsa_private() | ecdsa_params()] |
[eddsa_private() | eddsa_params()] |
mldsa_private() |
slh_dsa_private() |
engine_key_ref(),
Options :: pk_sign_verify_opts(),
Signature :: binary().Create a digital signature. 🖊️
The msg is either the binary "cleartext" data to be signed, or it's the hashed value of "cleartext" — i.e. the digest (plaintext).
Algorithm dss can only be used together with digest type sha. No mix-and-matching, bestie.
Uses the 3-tuple style for error handling.
See also public_key:sign/3. 🔥
💫 start() -> ok | {error, Reason :: term()}.
ngl bestie, don't use this one. It's deprecated — the page says it right there:
Deprecated:crypto:start/0is deprecated; useapplication:start(crypto)instead.
So what do you do instead? You use application:start(crypto). That's it, that's the move. 💅
🚨 WARNING: This function does not work if FIPS mode is to be enabled. FIPS mode will be disabled even if configuration parameterfips_modeis set totrue. Useapplication:start(crypto)instead.
Like… it'll quietly turn your FIPS mode off and you'll be sitting there confused. Not the vibe. Use application:start(crypto). 🫶
🌸 stop() -> ok | {error, Reason :: term()}.
Same energy, opposite direction — this one is also deprecated:
Deprecated:crypto:stop/0is deprecated; useapplication:stop(crypto)instead.
And yes, the replacement is exactly what you think it is: application:stop(crypto). Go off 💖
✨ strong_rand_bytes(N :: non_neg_integer()) -> binary().
Okay THIS one is the main character. It generates bytes with randomly uniform values 0..255 — pure chaotic good, but cryptographically 😌
Returns the result in a binary with N bytes. So you ask for N, you get N bytes back. Simple as that. 🎀
It uses a cryptographically secure PRNG seeded and periodically mixed with operating system provided entropy. By default this is the RAND_bytes method from OpenSSL. So like… it's getting its randomness from the OS, and it keeps stirring it up. Obsessed with the diligence honestly. 🔥
💀 Heads up: may raise exception error:low_entropy in case the random generator failed due to lack of secure "randomness".
So if your entropy runs dry, it does NOT just shrug and hand you mid randomness — it throws. Which is the correct behaviour, tbh. Respect. 👑
🦋 strong_rand_range(Range :: pos_integer()) -> N :: non_neg_integer(); (Range :: binary()) -> N :: binary().
Generate a random integer in a specified range. Exactly what it says on the tin, no notes. 💅
The returned random integer is in the interval is 0 =< N < Range. So like, 0 is in, Range itself is not. Half-open interval supremacy fr fr. 🌈
It uses the crypto library random number generator BN_rand_range.
The types do a lil shape-shifty thing here and it's lowkey iconic:
- If the
Rangeargument is apos_integer/0the return value is anon_neg_integer/0. - If the
Rangeargument is a positive integer in abinary/0, the return value is a non-negative integer in abinary/0.
In ↔ out, matching forms, no drama. 🫶
😭 Same warning as its sibling: may raise exception error:low_entropy in case the random generator failed due to lack of secure "randomness".
🧚 supports(Type) -> Support
supports(Type) -> Support
when
Type ::
hashs | ciphers | kems | public_keys | macs |
curves | rsa_opts,
Support ::
Hashs | Ciphers | KEMs | PKs | Macs | Curves |
RSAopts,
Hashs ::
[sha1() |
sha2() |
sha3() |
sha3_xof() |
blake2() |
ripemd160 |
compatibility_only_hash()],
Ciphers :: [cipher()],
KEMs :: [kem()],
PKs ::
[rsa | dss | ecdsa | dh | ecdh | eddh |
ec_gf2m],
Macs :: [hmac | cmac | poly1305],
Curves ::
[ec_named_curve() |
edwards_curve_dh() |
edwards_curve_ed()],
RSAopts :: [rsa_sign_verify_opt() | rsa_opt()].Get which crypto algorithms that are supported by the underlying libcrypto library. So it's like a vibe check on your OpenSSL — "what you got for me?" 💅
Pass in one of those Type atoms and it hands back the list of what's actually available. Very "tell me what I'm working with" of it. 💖
And for the detail on the hash and cipher algorithms specifically, see hash_info/1 and cipher_info/1. iykyk 🌟
💜 verify(Algorithm, DigestType, Msg, Signature, Key, Options) -> Result
verify(Algorithm, DigestType, Msg, Signature, Key, Options) ->
Result
when
Algorithm :: pk_sign_verify_algs(),
DigestType ::
rsa_digest_type() |
dss_digest_type() |
ecdsa_digest_type() |
none,
Msg :: iodata() | {digest, iodata()},
Signature :: binary(),
Key ::
rsa_public() |
dss_public() |
[ecdsa_public() | ecdsa_params()] |
[eddsa_public() | eddsa_params()] |
mldsa_public() |
slh_dsa_public() |
engine_key_ref(),
Options :: pk_sign_verify_opts(),
Result :: boolean().Verify a digital signature. The moment of truth, bestie — is this signature real or is somebody lying to you? 🔍
The msg is either the binary "cleartext" data to be signed or it is the hashed value of "cleartext" i.e. the digest (plaintext). So you can hand it the raw stuff, or you can hand it the already-digested stuff. Your call. 🎀
⚠️ Algorithmdsscan only be used together with digest typesha. That's the pairing, don't fight it. 😤
Uses the 3-tuple style for error handling. Very Erlang of it, very correct. ✅
See also public_key:verify/4. 🌈
okay bestie that's a wrap on the whole crypto(3) glow-up 💖 every last flag, type, warning and error:low_entropy accounted for, no crumbs left behind. This page came from Ericsson AB, it's crypto 5.9.3, and it lives at section crypto(3) — so go forth, hash responsibly, and never let a low-entropy PRNG ruin your day. periodt. 👑✨💅
📦 where this page comes from
- ubuntu stonking: erlang-doc 1:29.0.6+dfsg-1 · Apache-2.0
- 💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on : a language model's rewrite of the original, under its terms