RSA key generation is only available if the runtime was built with dirty scheduler support. Otherwise, attempting to generate an RSA key will throw exception error:notsup
.
crypto
Crypto Functions
This module provides a set of cryptographic functions.
Hash functions - Secure Hash Standard
, The MD5 Message Digest Algorithm (RFC 1321)
and The MD4 Message Digest Algorithm (RFC 1320)
Hmac functions - Keyed-Hashing for Message Authentication (RFC 2104)
Cmac functions - The AES-CMAC Algorithm (RFC 4493)
Block ciphers - DES and AES in Block Cipher Modes - ECB, CBC, CFB, OFB, CTR and GCM
Digital signatures Digital Signature Standard (DSS)
and Elliptic Curve Digital Signature Algorithm (ECDSA)
gcm: Dworkin, M., "Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC", National Institute of Standards and Technology SP 800- 38D, November 2007.
key_value() = integer() | binary()
Always binary()
when used as return value
rsa_public() = [key_value()] = [E, N]
Where E is the public exponent and N is public modulus.
rsa_private() = [key_value()] = [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() = [key_value()] = [P, Q, G, Y]
Where P, Q and G are the dss parameters and Y is the public key.
dss_private() = [key_value()] = [P, Q, G, X]
Where P, Q and G are the dss parameters and X is the private key.
srp_public() = key_value()
Where is A
or B
from SRP design
srp_private() = key_value()
Where is a
or b
from SRP design
Where Verifier is v
, Generator is g
and Prime isN
, DerivedKey is X
, and Scrambler is u
(optional will be generated if not provided) from SRP design
Version = '3' | '6' | '6a'
dh_public() = key_value()
dh_private() = key_value()
dh_params() = [key_value()] = [P, G] | [P, G, PrivateKeyBitLength]
ecdh_public() = key_value()
ecdh_private() = key_value()
ecdh_params() = ec_named_curve() | ec_explicit_curve()
ec_explicit_curve() = {ec_field(), Prime :: key_value(), Point :: key_value(), Order :: integer(), CoFactor :: none | integer()}
ec_field() = {prime_field, Prime :: integer()} | {characteristic_two_field, M :: integer(), Basis :: ec_basis()}
ec_basis() = {tpbasis, K :: non_neg_integer()} | {ppbasis, K1 :: non_neg_integer(), K2 :: non_neg_integer(), K3 :: non_neg_integer()} | onbasis
ec_named_curve() -> sect571r1| sect571k1| sect409r1| sect409k1| secp521r1| secp384r1| secp224r1| secp224k1| secp192k1| secp160r2| secp128r2| secp128r1| sect233r1| sect233k1| sect193r2| sect193r1| sect131r2| sect131r1| sect283r1| sect283k1| sect163r2| secp256k1| secp160k1| secp160r1| secp112r2| secp112r1| sect113r2| sect113r1| sect239k1| sect163r1| sect163k1| secp256r1| secp192r1| brainpoolP160r1| brainpoolP160t1| brainpoolP192r1| brainpoolP192t1| brainpoolP224r1| brainpoolP224t1| brainpoolP256r1| brainpoolP256t1| brainpoolP320r1| brainpoolP320t1| brainpoolP384r1| brainpoolP384t1| brainpoolP512r1| brainpoolP512t1
Note that the sect curves are GF2m (characteristic two) curves and are only supported if the underlying OpenSSL has support for them. See also crypto:supports/0
stream_cipher() = rc4 | aes_ctr
block_cipher() = aes_cbc | aes_cfb8 | aes_cfb128 | aes_ige256 | blowfish_cbc | blowfish_cfb64 | des_cbc | des_cfb | des3_cbc | des3_cfb | des_ede3 | rc2_cbc
aead_cipher() = aes_gcm | chacha20_poly1305
stream_key() = aes_key() | rc4_key()
block_key() = aes_key() | blowfish_key() | des_key()| des3_key()
aes_key() = iodata()
Key length is 128, 192 or 256 bits
rc4_key() = iodata()
Variable key length from 8 bits up to 2048 bits (usually between 40 and 256)
blowfish_key() = iodata()
Variable key length from 32 bits up to 448 bits
des_key() = iodata()
Key length is 64 bits (in CBC mode only 8 bits are used)
des3_key() = [binary(), binary(), binary()]
Each key part is 64 bits (in CBC mode only 8 bits are used)
digest_type() = md5 | sha | sha224 | sha256 | sha384 | sha512
hash_algorithms() = md5 | ripemd160 | sha | sha224 | sha256 | sha384 | sha512
md4 is also supported for hash_init/1 and hash/2. Note that both md4 and md5 are recommended only for compatibility with existing applications.
cipher_algorithms() = aes_cbc | aes_cfb8 | aes_cfb128 | aes_ctr | aes_gcm | aes_ige256 | blowfish_cbc | blowfish_cfb64 | chacha20_poly1305 | des_cbc | des_cfb | des3_cbc | des3_cfb | des_ede3 | rc2_cbc | rc4
public_key_algorithms() = rsa |dss | ecdsa | dh | ecdh | ec_gf2m
Note that ec_gf2m is not strictly a public key algorithm, but a restriction on what curves are supported with ecdsa and ecdh.
block_encrypt(Type, Key, PlainText) -> CipherText
Encrypt PlainText
according to Type
block cipher.
May throw exception notsup
in case the chosen Type
is not supported by the underlying OpenSSL implementation.
block_decrypt(Type, Key, CipherText) -> PlainText
Decrypt CipherText
according to Type
block cipher.
May throw exception notsup
in case the chosen Type
is not supported by the underlying OpenSSL implementation.
block_encrypt(Type, Key, Ivec, PlainText) -> CipherText
block_encrypt(AeadType, Key, Ivec, {AAD, PlainText}) -> {CipherText, CipherTag}
block_encrypt(aes_gcm, Key, Ivec, {AAD, PlainText, TagLength}) -> {CipherText, CipherTag}
Encrypt PlainText
according to Type
block cipher. IVec
is an arbitrary initializing vector.
In AEAD (Authenticated Encryption with Associated Data) mode, encrypt PlainText
according to Type
block cipher and calculate CipherTag
that also authenticates the AAD
(Associated Authenticated Data).
May throw exception notsup
in case the chosen Type
is not supported by the underlying OpenSSL implementation.
block_decrypt(Type, Key, Ivec, CipherText) -> PlainText
block_decrypt(AeadType, Key, Ivec, {AAD, CipherText, CipherTag}) -> PlainText | error
Decrypt CipherText
according to Type
block cipher. IVec
is an arbitrary initializing vector.
In AEAD (Authenticated Encryption with Associated Data) mode, decrypt CipherText
according 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 throw exception notsup
in case the chosen Type
is not supported by the underlying OpenSSL implementation.
bytes_to_integer(Bin) -> Integer
Convert binary representation, of an integer, to an Erlang integer.
compute_key(Type, OthersPublicKey, MyKey, Params) -> SharedSecret
Computes the shared secret from the private key and the other party's public key. See also public_key:compute_key/2
exor(Data1, Data2) -> Result
Performs bit-wise XOR (exclusive or) on the data supplied.
generate_key(Type, Params) -> {PublicKey, PrivKeyOut}
generate_key(Type, Params, PrivKeyIn) -> {PublicKey, PrivKeyOut}
Generates a public key of type Type
. See also public_key:generate_key/1
. May throw exception an exception of class error
:
badarg
: an argument is of wrong type or has an illegal value,low_entropy
: the random generator failed due to lack of secure "randomness",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 throw exception error:notsup
.
hash(Type, Data) -> Digest
Computes a message digest of type Type
from Data
.
May throw exception notsup
in case the chosen Type
is not supported by the underlying OpenSSL implementation.
hash_init(Type) -> Context
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 throw exception notsup
in case the chosen Type
is not supported by the underlying OpenSSL implementation.
hash_update(Context, Data) -> NewContext
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
.
hash_final(Context) -> Digest
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.
hmac(Type, Key, Data) -> Mac
hmac(Type, Key, Data, MacLength) -> Mac
Computes a HMAC of type Type
from Data
using Key
as the authentication key.
MacLength
will limit the size of the resultant Mac
.
hmac_init(Type, Key) -> Context
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.
hmac_update(Context, Data) -> NewContext
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 OpenSSL API.
hmac_final(Context) -> Mac
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.
hmac_final_n(Context, HashLen) -> Mac
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.
cmac(Type, Key, Data) -> Mac
cmac(Type, Key, Data, MacLength) -> Mac
Computes a CMAC of type Type
from Data
using Key
as the authentication key.
MacLength
will limit the size of the resultant Mac
.
info_fips() -> Status
Provides information about the FIPS operating status of crypto and the underlying OpenSSL 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
.
In FIPS mode all non-FIPS compliant algorithms are disabled and throw exception not_supported
. Check supports
that in FIPS mode returns the restricted list of available algorithms.
info_lib() -> [{Name,VerNum,VerStr}]
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 OpenSSL library used at runtime. In earlier OTP versions both numeric and text was taken from the library.
mod_pow(N, P, M) -> Result
Computes the function N^P mod M
.
next_iv(Type, Data) -> NextIVec
next_iv(Type, Data, IVec) -> NextIVec
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.
private_decrypt(Type, CipherText, PrivateKey, Padding) -> PlainText
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]
private_encrypt(Type, PlainText, PrivateKey, Padding) -> CipherText
PlainText
must be less than byte_size(N)-11
if rsa_pkcs1_padding
is used, and byte_size(N)
if rsa_no_padding
is used, where N is public modulus of the RSA 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]
public_decrypt(Type, CipherText, PublicKey, Padding) -> PlainText
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]
public_encrypt(Type, PlainText, PublicKey, Padding) -> CipherText
PlainText
must be less than byte_size(N)-11
if rsa_pkcs1_padding
is used, and byte_size(N)
if rsa_no_padding
is used, where N is public modulus of the RSA 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]
rand_seed(Seed) -> ok
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
throws low_entropy
rand_uniform(Lo, Hi) -> N
Generate a random number N, Lo =< N < Hi.
Uses the crypto
library pseudo-random number generator. Hi
must be larger than Lo
.
sign(Algorithm, DigestType, Msg, Key) -> binary()
The msg is either the binary "cleartext" data to be signed or it is the hashed value of "cleartext" i.e. the digest (plaintext).
Creates a digital signature.
Algorithm dss
can only be used together with digest type sha
.
See also public_key:sign/3
.
start() -> ok
Equivalent to application:start(crypto).
stop() -> ok
Equivalent to application:stop(crypto).
strong_rand_bytes(N) -> binary()
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 throw exception low_entropy
in case the random generator failed due to lack of secure "randomness".
rand_seed() -> rand:state()
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 on process dictionary before returning it as well. See also rand:seed/1
.
Example
_ = crypto:rand_seed(), _IntegerValue = rand:uniform(42), % [1; 42] _FloatValue = rand:uniform(). % [0.0; 1.0[
rand_seed_s() -> rand:state()
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
.
stream_init(Type, Key) -> State
Initializes the state for use in RC4 stream encryption stream_encrypt
and stream_decrypt
stream_init(Type, Key, IVec) -> State
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
.
stream_encrypt(State, PlainText) -> { NewState, CipherText}
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
.
stream_decrypt(State, CipherText) -> { NewState, PlainText }
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
.
supports() -> AlgorithmList
Can be used to determine which crypto algorithms that are supported by the underlying OpenSSL library
ec_curves() -> EllipticCurveList
Can be used to determine which named elliptic curves are supported.
ec_curve(NamedCurve) -> EllipticCurve
Return the defining parameters of a elliptic curve.
verify(Algorithm, DigestType, Msg, Signature, Key) -> boolean()
The msg is either the binary "cleartext" data or it is the hashed value of "cleartext" i.e. the digest (plaintext).
Verifies a digital signature
Algorithm dss
can only be used together with digest type sha
.
See also public_key:verify/4
.
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Licensed under the Apache License, Version 2.0.