crypto
Module
Module Summary
Description
This module provides a set of cryptographic functions.
 Hash functions
 MACs  Message Authentication Codes

 Hmac functions
 KeyedHashing for Message Authentication [RFC 2104]
 Cmac functions
 The AESCMAC Algorithm [RFC 4493]
 POLY1305
 ChaCha20 and Poly1305 for IETF Protocols [RFC 7539]
 Symmetric Ciphers

 DES, 3DES and AES
 Block Cipher Techniques [NIST]
 Blowfish
 Fast Software Encryption, Cambridge Security Workshop Proceedings (December 1993), SpringerVerlag, 1994, pp. 191204.
 Chacha20
 ChaCha20 and Poly1305 for IETF Protocols [RFC 7539]
 Chacha20_poly1305
 ChaCha20 and Poly1305 for IETF Protocols [RFC 7539]
 Modes

 ECB, CBC, CFB, OFB and CTR
 Recommendation for Block Cipher Modes of Operation: Methods and Techniques [NIST SP 80038A]
 GCM
 Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC [NIST SP 80038D]
 CCM
 Recommendation for Block Cipher Modes of Operation: The CCM Mode for Authentication and Confidentiality [NIST SP 80038C]
 Asymetric Ciphers  Public Key Techniques
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.
Data Types
Ciphers
Stream ciphers for stream_encrypt/2 and stream_decrypt/2 .
cbc_cipher() 
cfb_cipher() 
aes_cbc128 
aes_cbc256 
aes_ige256 
blowfish_ofb64 
des3_cbf 
des_ede3 
rc2_cbc
cbc_cipher() = des_cbc  des3_cbc  aes_cbc  blowfish_cbc
cfb_cipher() =
aes_cfb128  aes_cfb8  blowfish_cfb64  des3_cfb  des_cfb
Block ciphers with initialization vector for block_encrypt/4 and block_decrypt/4 .
Block ciphers without initialization vector for block_encrypt/3 and block_decrypt/3 .
Ciphers with simultaneous MACcalculation or MACchecking. block_encrypt/4 and block_decrypt/4 .
Digests
sha2() = sha224  sha256  sha384  sha512
sha3() = sha3_224  sha3_256  sha3_384  sha3_512
The compatibility_only_hash() algorithms are recommended only for compatibility with existing applications.
Elliptic Curves
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
edwards_curve_dh() = x25519  x448
edwards_curve_ed() = ed25519  ed448
Note that some curves are disabled if FIPS is enabled.
{Field :: ec_field(),
Curve :: ec_curve(),
BasePoint :: binary(),
Order :: binary(),
CoFactor :: none  binary()}
ec_field() = ec_prime_field()  ec_characteristic_two_field()
ec_curve() =
{A :: binary(), B :: binary(), Seed :: none  binary()}
Parametric curve definition.
ec_characteristic_two_field() =
{characteristic_two_field,
M :: integer(),
Basis :: ec_basis()}
ec_basis() =
{tpbasis, K :: integer() >= 0} 
{ppbasis,
K1 :: integer() >= 0,
K2 :: integer() >= 0,
K3 :: integer() >= 0} 
onbasis
Curve definition details.
Keys
For keylengths, ivsizes and blocksizes see the User's Guide.
A key for des3 is a list of three iolists
Always binary() when used as return value
Public/Private Keys
rsa_private() = [key_integer()]
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,P2 are first and second prime factors. E1,E2 are first and second exponents. C is the CRT coefficient. Terminology is taken from RFC 3447.
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.
ecdsa_private() = key_integer()
ecdsa_params() = ec_named_curve()  ec_explicit_curve()
srp_public() = key_integer()
Where is A or B from SRP design
srp_private() = key_integer()
Where is a or b from SRP design
{user, srp_user_gen_params()}  {host, srp_host_gen_params()}
srp_comp_params() =
{user, srp_user_comp_params()} 
{host, srp_host_comp_params()}
srp_user_gen_params() = [DerivedKey::binary(), Prime::binary(), Generator::binary(), Version::atom()]
srp_host_gen_params() = [Verifier::binary(), Prime::binary(), Version::atom() ]
srp_user_comp_params() = [DerivedKey::binary(), Prime::binary(), Generator::binary(), Version::atom()  ScramblerArg::list()]
srp_host_comp_params() = [Verifier::binary(), Prime::binary(), Version::atom()  ScramblerArg::list()]
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'
Public Key Ciphers
Algorithms for public key encrypt/decrypt. Only RSA is supported.
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_sslv23_padding 
rsa_x931_padding 
rsa_no_padding
Options for public key encrypt/decrypt. Only RSA is supported.
The RSA options are experimental.
The exact set of options and there syntax may be changed without prior notice.
Those option forms are kept only for compatibility and should not be used in new code.
Public Key Sign and Verify
Algorithms for sign and verify.
rsa_sign_verify_opt() =
{rsa_padding, rsa_sign_verify_padding()} 
{rsa_pss_saltlen, integer()}
rsa_sign_verify_padding() =
rsa_pkcs1_padding 
rsa_pkcs1_pss_padding 
rsa_x931_padding 
rsa_no_padding
Options for sign and verify.
The RSA options are experimental.
The exact set of options and there syntax may be changed without prior notice.
DiffieHellman Keys and parameters
dh_params() = [P, G]  [P, G, PrivateKeyBitLength]
ecdh_private() = key_integer()
ecdh_params() =
ec_named_curve()  edwards_curve_dh()  ec_explicit_curve()
Types for Engines
#{engine := engine_ref(),
key_id := key_id(),
password => password(),
term() => term()}
engine_ref() = term()
The result of a call to engine_load/3.
Identifies the key to be used. The format depends on the loaded engine. It is passed to the ENGINE_load_(privatepublic)_key functions in libcrypto.
The password of the key stored in an engine.
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
Pre and Post commands for engine_load/3 and /4.
Internal data types
Contexts with an internal state that should not be manipulated but passed between function calls.
Exports
OTP 18.0 
Encrypt PlainText according to Type block cipher.
May raise exception error:notsup in case the chosen Type is not supported by the underlying libcrypto implementation.
For keylengths and blocksizes see the User's Guide.
OTP 18.0 
Decrypt CipherText according to Type block cipher.
May raise exception error:notsup in case the chosen Type is not supported by the underlying libcrypto implementation.
For keylengths and blocksizes see the User's Guide.
OTP R16B01 
OTP R16B01 
OTP R16B01 
Types
Encrypt PlainText according to Type block cipher. IVec is an arbitrary initializing vector.
In AEAD (Authenticated Encryption with Associated Data) mode, encrypt PlainTextaccording to Type block cipher and calculate CipherTag that also authenticates the AAD (Associated Authenticated Data).
May raise exception error:notsup in case the chosen Type is not supported by the underlying libcrypto implementation.
For keylengths, ivsizes and blocksizes see the User's Guide.
OTP R16B01 
OTP R16B01 
Types
Decrypt CipherText according to Type block cipher. IVec is an arbitrary initializing vector.
In AEAD (Authenticated Encryption with Associated Data) mode, decrypt CipherTextaccording to Type block cipher and check the authenticity the PlainText and AAD (Associated Authenticated Data) using the CipherTag. May return error if the decryption or validation fail's
May raise exception error:notsup in case the chosen Type is not supported by the underlying libcrypto implementation.
For keylengths, ivsizes and blocksizes see the User's Guide.
OTP R16B01 
Convert binary representation, of an integer, to an Erlang integer.
OTP R16B01 
Types
dh_private()  ecdh_private()  {srp_public(), srp_private()}
Computes the shared secret from the private key and the other party's public key. See also public_key:compute_key/2
Performs bitwise XOR (exclusive or) on the data supplied.
OTP R16B01 
OTP R16B01 
Types
dh_public()  ecdh_public()  rsa_public()  srp_public()
undefined 
dh_private() 
ecdh_private() 
rsa_private() 
{srp_public(), srp_private()}
dh_private() 
ecdh_private() 
rsa_private() 
{srp_public(), srp_private()}
dh_params()  ecdh_params()  rsa_params()  srp_comp_params()
Generates a public key of type Type. See also public_key:generate_key/1. May raise exception:
 error:badarg: an argument is of wrong type or has an illegal value,
 error:low_entropy: the random generator failed due to lack of secure "randomness",
 error:computation_failed: the computation fails of another reason than low_entropy.
RSA key generation is only available if the runtime was built with dirty scheduler support. Otherwise, attempting to generate an RSA key will raise exception error:notsup.
OTP R15B02 
Types
sha1() 
sha2() 
sha3() 
ripemd160 
compatibility_only_hash()
Computes a message digest of type Type from Data.
May raise exception error:notsup in case the chosen Type is not supported by the underlying libcrypto implementation.
OTP R15B02 
Initializes the context for streaming hash operations. Type determines which digest to use. The returned context should be used as argument to hash_update.
May raise exception error:notsup in case the chosen Type is not supported by the underlying libcrypto implementation.
OTP R15B02 
Updates the digest represented by Context using the given Data. Context must have been generated using hash_init or a previous call to this function. Data can be any length. NewContext must be passed into the next call to hash_update or hash_final.
OTP R15B02 
Finalizes the hash operation referenced by Context returned from a previous call to hash_update. The size of Digest is determined by the type of hash function used to generate it.
OTP R16B 
OTP R16B 
Types
Computes a HMAC of type Type from Data using Key as the authentication key.
MacLength will limit the size of the resultant Mac.
OTP R14B03 
Types
Initializes the context for streaming HMAC operations. Type determines which hash function to use in the HMAC operation. Key is the authentication key. The key can be any length.
OTP R14B03 
Updates the HMAC represented by Context using the given Data. Context must have been generated using an HMAC init function (such as hmac_init). Data can be any length. NewContext must be passed into the next call to hmac_update or to one of the functions hmac_final and hmac_final_n
Do not use a Context as argument in more than one call to hmac_update or hmac_final. The semantics of reusing old contexts in any way is undefined and could even crash the VM in earlier releases. The reason for this limitation is a lack of support in the underlying libcrypto API.
OTP R14B03 
Finalizes the HMAC operation referenced by Context. The size of the resultant MAC is determined by the type of hash function used to generate it.
OTP R14B03 
Finalizes the HMAC operation referenced by Context. HashLen must be greater than zero. Mac will be a binary with at most HashLen bytes. Note that if HashLen is greater than the actual number of bytes returned from the underlying hash, the returned hash will have fewer than HashLen bytes.
OTP 20.0 
OTP 20.0 
Types
cbc_cipher() 
cfb_cipher() 
blowfish_cbc 
des_ede3 
rc2_cbc
Computes a CMAC of type Type from Data using Key as the authentication key.
MacLength will limit the size of the resultant Mac.
OTP 20.0 
Provides information about 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 enable_fips_mode/1 about how to enable FIPS mode.
In FIPS mode all nonFIPS compliant algorithms are disabled and raise exception error:notsup. Check supports that in FIPS mode returns the restricted list of available algorithms.
OTP 21.1 
Types
Enables (Enable = true) or disables (Enable = false) FIPS mode. Returns true if the operation was successful or false otherwise.
Note that to enable FIPS mode succesfully, OTP must be built with the configure option enablefips, and the underlying libcrypto must also support FIPS.
See also info_fips/0.
Types
Provides 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.
> info_lib().
[{<<"OpenSSL">>,269484095,<<"OpenSSL 1.1.0c 10 Nov 2016"">>}]
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.
OTP R16B01 
Types
Computes the function N^P mod M.
next_iv(Type :: cbc_cipher(), Data) > NextIVec 
OTP R16B01 
OTP R16B01 
Types
Returns the initialization vector to be used in the next iteration of encrypt/decrypt of type Type. Data is the encrypted data from the previous iteration step. The IVec argument is only needed for des_cfb as the vector used in the previous iteration step.
OTP 21.1 
Types
Computes a POLY1305 message authentication code (Mac) from Data using Key as the authentication key.
OTP R16B01 
Types
Decrypts the CipherText, encrypted with public_encrypt/4 (or 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]
OTP R16B01 
Types
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]
OTP R16B01 
Types
Decrypts the CipherText, encrypted with private_encrypt/4(or 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_public/[2,3]
OTP R16B01 
Types
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]
OTP 17.0 
Set the seed for PRNG to the given binary. 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 raises error:low_entropy
Types
Generate a random number N, Lo =< N < Hi. Uses the crypto library pseudorandom number generator. Hi must be larger than Lo.
Equivalent to application:start(crypto).
Equivalent to application:stop(crypto).
OTP R14B03 
Generates N bytes randomly uniform 0..255, and returns the result in a binary. Uses a cryptographically secure prng seeded and periodically mixed with operating system provided entropy. By default this is the RAND_bytes method from OpenSSL.
May raise exception error:low_entropy in case the random generator failed due to lack of secure "randomness".
rand_seed() > rand:state()

OTP 20.0 
Creates state object for random number generation, in order to generate cryptographically strong random numbers (based on OpenSSL's BN_rand_range), and saves it in the process dictionary before returning it as well. See also rand:seed/1 and rand_seed_s/0.
When using the state object from this function the rand functions using it may raise exception error:low_entropy in case the random generator failed due to lack of secure "randomness".
Example
_ = crypto:rand_seed(), _IntegerValue = rand:uniform(42), % [1; 42] _FloatValue = rand:uniform(). % [0.0; 1.0[
rand_seed_s() > rand:state()

OTP 20.0 
Creates state object for random number generation, in order to generate cryptographically strongly random numbers (based on OpenSSL's BN_rand_range). See also rand:seed_s/1.
When using the state object from this function the rand functions using it may raise exception error:low_entropy in case the random generator failed due to lack of secure "randomness".
The state returned from this function can not be used to get a reproducable random sequence as from the other rand functions, since reproducability does not match cryptographically safe.
The only supported usage is to generate one distinct random sequence from this start state.
OTP 21.0 
Types
Creates state object for random number generation, in order to generate cryptographically strong random numbers. See also rand:seed/1 and rand_seed_alg_s/1.
When using the state object from this function the rand functions using it may raise 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.
Example
_ = crypto:rand_seed_alg(crypto_cache), _IntegerValue = rand:uniform(42), % [1; 42] _FloatValue = rand:uniform(). % [0.0; 1.0[
OTP 21.0 
Types
Creates state object for random number generation, in order to generate cryptographically strongly random numbers. See also rand:seed_s/1.
If Alg is crypto this function behaves exactly like rand_seed_s/0.
If Alg is crypto_cache this function fetches random data with OpenSSL's RAND_bytes and caches it for speed using an internal word size of 56 bits that makes calculations fast on 64 bit machines.
When using the state object from this function the rand functions using it may raise 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.
The state returned from this function can not be used to get a reproducable random sequence as from the other rand functions, since reproducability does not match cryptographically safe.
In fact since random data is cached some numbers may get reproduced if you try, but this is unpredictable.
The only supported usage is to generate one distinct random sequence from this start state.
OTP R16B01 
Initializes the state for use in RC4 stream encryption stream_encrypt and stream_decrypt
For keylengths see the User's Guide.
OTP R16B01 
Initializes the state for use in streaming AES encryption using Counter mode (CTR). Key is the AES key and must be either 128, 192, or 256 bits long. IVec is an arbitrary initializing vector of 128 bits (16 bytes). This state is for use with stream_encrypt and stream_decrypt.
For keylengths and ivsizes see the User's Guide.
OTP R16B01 
Encrypts PlainText according to the stream cipher Type specified in stream_init/3. Text can be any number of bytes. The initial State is created using stream_init. NewState must be passed into the next call to stream_encrypt.
OTP R16B01 
Decrypts CipherText according to the stream cipher Type specified in stream_init/3. PlainText can be any number of bytes. The initial State is created using stream_init. NewState must be passed into the next call to stream_decrypt.
OTP R16B01 
Types
{hashs, Hashs} 
{ciphers, Ciphers} 
{public_keys, PKs} 
{macs, Macs} 
{curves, Curves} 
{rsa_opts, RSAopts}
[sha1() 
sha2() 
sha3() 
ripemd160 
compatibility_only_hash()]
[stream_cipher() 
block_cipher_with_iv() 
block_cipher_without_iv() 
aead_cipher()]
[ec_named_curve()  edwards_curve_dh()  edwards_curve_ed()]
Can be used to determine which crypto algorithms that are supported by the underlying libcrypto library
Note: the rsa_opts entry is in an experimental state and may change or be removed without notice. No guarantee for the accuarcy of the rsa option's value list should be assumed.
OTP 17.0 
Types
ec_named_curve()  edwards_curve_dh()  edwards_curve_ed()
Can be used to determine which named elliptic curves are supported.
OTP 17.0 
Return the defining parameters of a elliptic curve.
OTP R16B01 
OTP 20.1 
Types
rsa_digest_type() 
dss_digest_type() 
ecdsa_digest_type() 
none
rsa_private() 
dss_private() 
[ecdsa_private()  ecdsa_params()] 
[eddsa_private()  eddsa_params()] 
engine_key_ref()
Creates a digital signature.
The msg is either the binary "cleartext" data to be signed or it is the hashed value of "cleartext" i.e. the digest (plaintext).
Algorithm dss can only be used together with digest type sha.
See also public_key:sign/3.
OTP R16B01 
OTP 20.1 
Types
rsa_digest_type()  dss_digest_type()  ecdsa_digest_type()
rsa_public() 
dss_public() 
[ecdsa_public()  ecdsa_params()] 
[eddsa_public()  eddsa_params()] 
engine_key_ref()
Verifies a digital signature
The msg is either the binary "cleartext" data to be signed or it is the hashed value of "cleartext" i.e. the digest (plaintext).
Algorithm dss can only be used together with digest type sha.
See also public_key:verify/4.
OTP 20.2 
Types
Fetches the corresponding public key from a private key stored in an Engine. The key must be of the type indicated by the Type parameter.
OTP 20.2 
Types
Returns a list of all possible engine methods.
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.
OTP 20.2 
Types
{ok, Engine :: engine_ref()}  {error, Reason :: term()}
Loads the OpenSSL engine given by EngineId if it is available and then returns ok and an engine handle. This function is the same as calling engine_load/4 with EngineMethods set to a list of all the possible methods. An error tuple is returned if the engine can't be loaded.
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.
See also the chapter Engine Load in the User's Guide.
OTP 20.2 
Types
{ok, Engine :: engine_ref()}  {error, Reason :: term()}
Loads the OpenSSL engine given by EngineId if it is available and then returns ok and an engine handle. An error tuple is returned if the engine can't be loaded.
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.
See also the chapter Engine Load in the User's Guide.
OTP 20.2 
Unloads the OpenSSL engine given by Engine. An error tuple is returned if the engine can't be unloaded.
The function raises a error:badarg if the parameter is in wrong format. 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.
OTP 21.0.6 
Types
{ok, Engine :: engine_ref()}  {error, Reason :: term()}
Get a reference to an already loaded engine with EngineId. An error tuple is returned if the engine can't be unloaded.
The function raises a error:badarg if the parameter is in wrong format. 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.
OTP 20.2 
Sends ctrl commands to the OpenSSL engine given by Engine. This function is the same as calling engine_ctrl_cmd_string/4 with Optional set to false.
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.
OTP 20.2 
Types
Sends ctrl commands to the OpenSSL engine given by 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 doesn't 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.
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.
OTP 21.0.6 
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.
OTP 21.0.6 
Remove the engine from 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.
OTP 21.0.6 
Return the ID for the engine, or an empty binary if there is no id set.
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.
OTP 21.0.6 
Return the name (eg a description) for the engine, or an empty binary if there is no name set.
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.
OTP 20.2 
Types
List the id's of all engines in OpenSSL's internal list.
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.
OTP 21.0.6 
Types
{ok, Engine :: engine_ref()}  {error, Reason :: term()}
Loads the OpenSSL engine given by EngineId and the path to the dynamic library implementing the engine. This function is the same as calling ensure_engine_loaded/3 with EngineMethods set to a list of all the possible methods. An error tuple is returned if the engine can't be loaded.
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.
See also the chapter Engine Load in the User's Guide.
OTP 21.0.6 
Types
{ok, Engine :: engine_ref()}  {error, Reason :: term()}
Loads the OpenSSL engine given by EngineId and the path to the dynamic library implementing the engine. This function differs from the normal engine_load in that sense it also add the engine id to the internal list in OpenSSL. Then in the following calls to the function it just fetch the reference to the engine instead of loading it again. An error tuple is returned if the engine can't be loaded.
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.
See also the chapter Engine Load in the User's Guide.
OTP 21.0.6 
Unloads an engine loaded with the ensure_engine_loaded function. It both removes the label from the OpenSSL internal engine list and unloads the engine. This function is the same as calling ensure_engine_unloaded/2 with EngineMethods set to a list of all the possible methods. An error tuple is returned if the engine can't be unloaded.
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.
See also the chapter Engine Load in the User's Guide.
OTP 21.0.6 
Types
Unloads an engine loaded with the ensure_engine_loaded function. It both removes the label from the OpenSSL internal engine list and unloads the engine. An error tuple is returned if the engine can't be unloaded.
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.
See also the chapter Engine Load in the User's Guide.