Crypto Functions
This module provides a set of cryptographic functions.
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.
Types
cipher() = cipher_no_iv() | cipher_iv() | cipher_aead()
cipher_no_iv() =
aes_128_ecb | aes_192_ecb | aes_256_ecb | blowfish_ecb |
des_ecb | rc4
cipher_iv() =
aes_128_cbc | aes_192_cbc | aes_256_cbc | aes_128_cfb128 |
aes_192_cfb128 | aes_256_cfb128 | aes_128_cfb8 |
aes_192_cfb8 | aes_256_cfb8 | aes_128_ctr | aes_192_ctr |
aes_256_ctr | aes_ige256 | blowfish_cbc | blowfish_cfb64 |
blowfish_ofb64 | chacha20 | des_ede3_cbc | des_ede3_cfb |
des_cbc | des_cfb | rc2_cbc
cipher_aead() =
aes_128_ccm | aes_192_ccm | aes_256_ccm | aes_128_gcm |
aes_192_gcm | aes_256_gcm | chacha20_poly1305
Ciphers known by the CRYPTO application when using the new API.
Note that this list might be reduced if the underlying libcrypto does not support all of them.
block_cipher_with_iv() =
cbc_cipher() | cfb_cipher() | blowfish_ofb64 | aes_ige256
block_cipher_without_iv() = ecb_cipher()
stream_cipher() = ctr_cipher() | chacha20 | rc4
aead_cipher() = aes_gcm | aes_ccm | chacha20_poly1305
cbc_cipher() =
aes_128_cbc | aes_192_cbc | aes_256_cbc | blowfish_cbc |
des_cbc | des_ede3_cbc | rc2_cbc |
retired_cbc_cipher_aliases()
cfb_cipher() =
aes_128_cfb128 | aes_192_cfb128 | aes_256_cfb128 |
aes_128_cfb8 | aes_192_cfb8 | aes_256_cfb8 | blowfish_cfb64 |
des_cfb | des_ede3_cfb |
retired_cfb_cipher_aliases()
ctr_cipher() =
aes_128_ctr | aes_192_ctr | aes_256_ctr |
retired_ctr_cipher_aliases()
ecb_cipher() =
aes_128_ecb | aes_192_ecb | aes_256_ecb | blowfish_ecb |
retired_ecb_cipher_aliases()
Ciphers known by the CRYPTO application when using the old API.
Note that this list might be reduced if the underlying libcrypto does not support all of them.
retired_cbc_cipher_aliases() =
aes_cbc | aes_cbc128 | aes_cbc256 | des3_cbc | des_ede3
retired_cfb_cipher_aliases() =
aes_cfb8 | aes_cfb128 | des3_cbf | des3_cfb | des_ede3_cbf
retired_ctr_cipher_aliases() = aes_ctr
retired_ecb_cipher_aliases() = aes_ecb
Alternative, old names of ciphers known by the CRYPTO application when using the old API. See Retired cipher names for names to use instead to be prepared for an easy convertion to the new API.
Note that this list might be reduced if the underlying libcrypto does not support all of them.
hash_algorithm() =
sha1() |
sha2() |
sha3() |
blake2() |
ripemd160 |
compatibility_only_hash()
hmac_hash_algorithm() =
sha1() | sha2() | sha3() | compatibility_only_hash()
sha1() = sha
sha2() = sha224 | sha256 | sha384 | sha512
sha3() = sha3_224 | sha3_256 | sha3_384 | sha3_512
blake2() = blake2b | blake2s
compatibility_only_hash() = md5 | md4
The compatibility_only_hash()
algorithms are recommended only for compatibility with existing applications.
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
edwards_curve_dh() = x25519 | x448
edwards_curve_ed() = ed25519 | ed448
Note that some curves are disabled if FIPS is enabled.
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_curve() =
{A :: binary(), B :: binary(), Seed :: none | binary()}
Parametric curve definition.
ec_prime_field() = {prime_field, Prime :: integer()}
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.
key() = iodata()
des3_key() = [key()]
For keylengths, iv-sizes and blocksizes see the User's Guide.
A key for des3 is a list of three iolists
key_integer() = integer() | binary()
Always binary()
when used as return value
rsa_public() = [key_integer()]
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
dss_public() = [key_integer()]
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.
ecdsa_public() = key_integer()
ecdsa_private() = key_integer()
ecdsa_params() = ec_named_curve() | ec_explicit_curve()
srp_public() = key_integer()
srp_private() = key_integer()
srp_public() = key_integer()
Where is A
or B
from
srp_private() = key_integer()
Where is a
or b
from
srp_gen_params() =
{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
pk_encrypt_decrypt_algs() = rsa
Algorithms for public key encrypt/decrypt. Only RSA is supported.
pk_encrypt_decrypt_opts() = [rsa_opt()] | rsa_compat_opts()
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.
Warning!
The RSA options are experimental.
The exact set of options and there syntax may be changed without prior notice.
rsa_compat_opts() = [{rsa_pad, rsa_padding()}] | rsa_padding()
Those option forms are kept only for compatibility and should not be used in new code.
pk_sign_verify_algs() = rsa | dss | ecdsa | eddsa
Algorithms for sign and verify.
pk_sign_verify_opts() = [rsa_sign_verify_opt()]
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.
dh_params() = [key_integer()]
dh_params() = [P, G] | [P, G, PrivateKeyBitLength]
ecdh_public() = key_integer()
ecdh_private() = key_integer()
ecdh_params() =
ec_named_curve() | edwards_curve_dh() | ec_explicit_curve()
engine_key_ref() =
#{engine := engine_ref(),
key_id := key_id(),
password => password(),
term() => term()}
engine_ref() = term()
The result of a call to engine_load/3.
key_id() = string() | binary()
Identifies the key to be used. The format depends on the loaded engine. It is passed to
the ENGINE_load_(private|public)_key
functions in libcrypto.
password() = string() | binary()
The password of the key stored in an engine.
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_cmnd() = {unicode:chardata(), unicode:chardata()}
Pre and Post commands for engine_load/3 and /4.
stream_state()
hmac_state()
hash_state()
crypto_state()
Contexts with an internal state that should not be manipulated but passed between function calls.
run_time_error() = no_return()
The exception error:badarg
signifies that one or more arguments are of wrong data type,
or are otherwise badly formed.
The exception error:notsup
signifies that the algorithm is known but is not supported
by current underlying libcrypto or explicitly disabled when building that.
For a list of supported algorithms, see supports/0.
descriptive_error() = no_return()
This is a more developed variant of the older run_time_error().
The exception is:
{Tag, {C_FileName,LineNumber}, Description} Tag = badarg | notsup | error C_FileName = string() LineNumber = integer() Description = string()
It is like the older type an exception of the error
class. In addition they contain
a descriptive text in English. That text is targeted to a developer. Examples are "Bad key size"
or "Cipher id is not an atom".
The 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". Thoose text usually needs searching the C-code to be understood.
To catch the exception, use for example:
try crypto:crypto_init(Ciph, Key, IV, true)
catch
error:{Tag, {C_FileName,LineNumber}, Description} ->
do_something(......)
.....
end
New API
Functions
crypto_init(Cipher, Key, EncryptFlag) ->
State | descriptive_error()
Cipher = cipher_no_iv()
Key = iodata()
EncryptFlag = boolean()
State = crypto_state()
As crypto_init/4 but for ciphers without IVs.
crypto_init(Cipher, Key, IV, EncryptFlag) ->
State | descriptive_error()
Cipher = cipher_iv()
Key = IV = iodata()
EncryptFlag = boolean()
State = crypto_state()
Part of the new API. Initializes a series of encryptions or decryptions and creates an internal state with a reference that is returned. The actual encryption or decryption is done by crypto_update/2.
For encryption, set the EncryptFlag
to true
. For decryption, set it to false
.
crypto_update(State, Data) -> Result | descriptive_error()
State = crypto_state()
Data = iodata()
Result = binary()
Part of the new API.
It does an actual crypto operation on a part of the full text. 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.
crypto_dyn_iv_init(Cipher, Key, EncryptFlag) ->
State | descriptive_error()
Cipher = cipher_iv()
Key = iodata()
EncryptFlag = boolean()
State = crypto_state()
Part of the new API. Initializes a series of encryptions or decryptions where the IV is provided later. The actual encryption or decryption is done by crypto_dyn_iv_update/3.
For encryption, set the EncryptFlag
to true
. For decryption, set it to false
.
crypto_dyn_iv_update(State, Data, IV) ->
Result | descriptive_error()
State = crypto_state()
Data = IV = iodata()
Result = binary()
Part of the new API.
Do an actual crypto operation on a part of the full text and the IV is supplied for each part.
The State
should be created with
crypto_dyn_iv_init/3.
crypto_one_time(Cipher, Key, Data, EncryptFlag) ->
Result | descriptive_error()
Cipher = cipher_no_iv()
Key = Data = iodata()
EncryptFlag = boolean()
Result = binary()
As crypto_one_time/5 but for ciphers without IVs.
crypto_one_time(Cipher, Key, IV, Data, EncryptFlag) ->
Result | descriptive_error()
Cipher = cipher_iv()
Key = IV = Data = iodata()
EncryptFlag = boolean()
Result = binary()
Part of the new API.
Do a complete encrypt or decrypt of the full text in the argument Data
.
For encryption, set the EncryptFlag
to true
. For decryption, set it to false
.
crypto_one_time_aead(Cipher, Key, IV, InText, AAD,
EncFlag :: true) ->
Result | descriptive_error()
Cipher = cipher_aead()
Key = IV = InText = AAD = iodata()
Result = EncryptResult
EncryptResult = {OutCryptoText, OutTag}
OutCryptoText = OutTag = binary()
crypto_one_time_aead(Cipher, Key, IV, InText, AAD, TagOrTagLength,
EncFlag) ->
Result | descriptive_error()
Cipher = cipher_aead()
Key = IV = InText = AAD = iodata()
TagOrTagLength = EncryptTagLength | DecryptTag
EncryptTagLength = integer() >= 0
DecryptTag = iodata()
EncFlag = boolean()
Result = EncryptResult | DecryptResult
EncryptResult = {OutCryptoText, OutTag}
DecryptResult = OutPlainText | error
OutCryptoText = OutTag = OutPlainText = binary()
Part of the new API. Do a complete encrypt or decrypt with an AEAD cipher of the full text.
For encryption, set the EncryptFlag
to true
and set the TagOrTagLength
to the wanted size of the tag, that is, the tag length. If the default length is wanted, the
crypto_aead/6
form may be used.
For decryption, set the EncryptFlag
to false
and put the tag to be checked
in the argument TagOrTagLength
.
supports(Type) -> Support
Type = hashs | ciphers | public_keys | macs | curves | rsa_opts
Support = Hashs | Ciphers | PKs | Macs | Curves | RSAopts
Hashs =
[sha1() |
sha2() |
sha3() |
blake2() |
ripemd160 |
compatibility_only_hash()]Ciphers = [cipher()]
PKs = [rsa | dss | ecdsa | dh | ecdh | ec_gf2m]
Macs = [hmac | cmac | poly1305]
Curves =
[ec_named_curve() | edwards_curve_dh() | edwards_curve_ed()]RSAopts = [rsa_sign_verify_opt() | rsa_opt()]
Can be used to determine which crypto algorithms that are supported by the underlying libcrypto library
See hash_info/1 and cipher_info/1 for information about the hash and cipher algorithms.
API kept from previous versions
Functions
bytes_to_integer(Bin :: binary()) -> integer()
Convert binary representation, of an integer, to an Erlang integer.
compute_key(Type, OthersPublicKey, MyPrivateKey, Params) ->
SharedSecret
Type = dh | ecdh | 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()
Computes the shared secret from the private key and the other party's public key. See also public_key:compute_key/2
exor(Bin1 :: iodata(), Bin2 :: iodata()) -> binary()
Performs bit-wise XOR (exclusive or) on the data supplied.
generate_key(Type, Params) -> {PublicKey, PrivKeyOut}
Type = dh | ecdh | rsa | srp
PublicKey =
dh_public() | ecdh_public() | rsa_public() | srp_public()PrivKeyOut =
dh_private() |
ecdh_private() |
rsa_private() |
{srp_public(), srp_private()}Params =
dh_params() | ecdh_params() | rsa_params() | srp_gen_params()
generate_key(Type, Params, PrivKeyIn) -> {PublicKey, PrivKeyOut}
Type = dh | ecdh | rsa | srp
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() | 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 thanlow_entropy
.
Note!
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
.
hash(Type, Data) -> Digest
Type = hash_algorithm()
Data = iodata()
Digest = binary()
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.
hash_init(Type) -> State
Type = hash_algorithm()
State = hash_state()
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.
hash_update(State, Data) -> NewState
State = NewState = hash_state()
Data = iodata()
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(State) -> Digest
State = hash_state()
Digest = binary()
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
Type = hmac_hash_algorithm()
Key = Data = iodata()
Mac = binary()
hmac(Type, Key, Data, MacLength) -> Mac
Type = hmac_hash_algorithm()
Key = Data = iodata()
MacLength = integer()
Mac = binary()
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) -> State
Type = hmac_hash_algorithm()
Key = iodata()
State = hmac_state()
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(State, Data) -> NewState
Data = iodata()
State = NewState = hmac_state()
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
Warning!
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.
hmac_final(State) -> Mac
State = hmac_state()
Mac = binary()
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(State, HashLen) -> Mac
State = hmac_state()
HashLen = integer()
Mac = binary()
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
Type =
cbc_cipher() |
cfb_cipher() |
blowfish_cbc | des_ede3 | rc2_cbcKey = Data = iodata()
Mac = binary()
cmac(Type, Key, Data, MacLength) -> Mac
Type =
cbc_cipher() |
cfb_cipher() |
blowfish_cbc | des_ede3 | rc2_cbcKey = Data = iodata()
MacLength = integer()
Mac = binary()
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() -> not_supported | not_enabled | enabled
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.
Warning!
In FIPS mode all non-FIPS compliant algorithms are
disabled and raise exception error:notsup
. Check
supports that in
FIPS mode returns the restricted list of available
algorithms.
enable_fips_mode(Enable) -> Result
Enable = Result = boolean()
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 --enable-fips
,
and the underlying libcrypto must also support FIPS.
See also info_fips/0.
info_lib() -> [{Name, VerNum, VerStr}]
Name = binary()
VerNum = integer()
VerStr = binary()
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"">>}]
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.
hash_info(Type) -> Result | run_time_error()
Type = hash_algorithm()
Result =
#{size := integer(),
block_size := integer(),
type := integer()}
Provides a map with information about block_size, size and possibly other properties of the hash algorithm in question.
For a list of supported hash algorithms, see supports/0.
cipher_info(Type) -> Result | run_time_error()
Type = cipher()
Result =
#{key_length := integer(),
iv_length := integer(),
block_size := integer(),
mode := CipherModes,
type := undefined | integer()}CipherModes =
undefined | cbc_mode | ccm_mode | cfb_mode | ctr_mode |
ecb_mode | gcm_mode | ige_mode | ocb_mode | ofb_mode |
wrap_mode | xts_mode
Provides a map with information about block_size, key_length, iv_length and possibly other properties of the cipher algorithm in question.
Note!
The ciphers aes_cbc
, aes_cfb8
, aes_cfb128
, aes_ctr
,
aes_ecb
, aes_gcm
and aes_ccm
has no keylength in the Type
as opposed to for example aes_128_ctr
. They adapt to the length of
the key provided in the encrypt and decrypt function. Therefor it is impossible to return a valid keylength
in the map.
Always use a Type
with an explicit key length,
For a list of supported cipher algorithms, see supports/0.
mod_pow(N, P, M) -> Result
N = P = M = binary() | integer()
Result = binary() | error
Computes the function N^P mod M
.
next_iv(Type :: cbc_cipher(), Data) -> NextIVec
Data = iodata()
NextIVec = binary()
next_iv(Type :: des_cfb, Data, IVec) -> NextIVec
Data = iodata()
IVec = NextIVec = binary()
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.
poly1305(Key :: iodata(), Data :: iodata()) -> Mac
Mac = binary()
Computes a POLY1305 message authentication code (Mac
) from Data
using
Key
as the authentication key.
private_decrypt(Algorithm, CipherText, PrivateKey, Options) ->
PlainText
Algorithm = pk_encrypt_decrypt_algs()
CipherText = binary()
PrivateKey = rsa_private() | engine_key_ref()
Options = pk_encrypt_decrypt_opts()
PlainText = binary()
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(Algorithm, PlainText, PrivateKey, Options) ->
CipherText
Algorithm = pk_encrypt_decrypt_algs()
PlainText = binary()
PrivateKey = rsa_private() | engine_key_ref()
Options = pk_encrypt_decrypt_opts()
CipherText = binary()
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(Algorithm, CipherText, PublicKey, Options) ->
PlainText
Algorithm = pk_encrypt_decrypt_algs()
CipherText = binary()
PublicKey = rsa_public() | engine_key_ref()
Options = pk_encrypt_decrypt_opts()
PlainText = binary()
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(Algorithm, PlainText, PublicKey, Options) ->
CipherText
Algorithm = pk_encrypt_decrypt_algs()
PlainText = binary()
PublicKey = rsa_public() | engine_key_ref()
Options = pk_encrypt_decrypt_opts()
CipherText = binary()
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 :: binary()) -> 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
raises error:low_entropy
Lo, Hi, N = integer()
Generate a random number N, Lo =< N < Hi.
Uses the
crypto
library pseudo-random number generator.
Hi
must be larger than Lo
.
start() -> ok | {error, Reason :: term()}
Equivalent to application:start(crypto).
stop() -> ok | {error, Reason :: term()}
Equivalent to application:stop(crypto).
strong_rand_bytes(N :: integer() >= 0) -> 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 raise exception error: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 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()
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".
Note!
The state returned from this function cannot 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.
Alg = crypto | crypto_cache
Creates state object for random number generation, in order to generate cryptographically strong random numbers, and saves it in the process dictionary before returning it as well. 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".
Example
_ = crypto:rand_seed_alg(crypto_cache), _IntegerValue = rand:uniform(42), % [1; 42] _FloatValue = rand:uniform(). % [0.0; 1.0[
Alg = crypto_aes
Creates a state object for random number generation, in order to generate cryptographically unpredictable random numbers, and saves it in the process dictionary before returning it as well. See also rand_seed_alg_s/2.
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(). % again
Alg = crypto | crypto_cache
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
.
When using the state object from this function the
rand functions using it
may throw exception 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 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.
Alg = crypto_aes
Creates a state object for random number generation, in order to generate cryptographically unpredictable random numbers. See also rand_seed_alg/1.
To get a long period the Xoroshiro928 generator from the rand module is used as a counter (with period 2^928 - 1) and the generator states are scrambled through AES to create 58-bit pseudo random values.
The result should be statistically completely unpredictable random values, since the scrambling is cryptographically strong and the period is ridiculously long. But the generated numbers are not to be regarded as cryptographically strong since there is no re-keying schedule.
-
If you need cryptographically strong random numbers use rand_seed_alg_s/1 with
Alg =:= crypto
orAlg =:= crypto_cache
. -
If you need to be able to repeat the sequence use this function.
-
If you do not need the statistical quality of this function, there are faster algorithms in the rand module.
Thanks to the used generator the state object supports the
rand:jump/0,1
function with distance 2^512.
Numbers are generated in batches and cached for speed reasons.
The cache size can be changed from its default value using the
crypto app's
configuration parameter rand_cache_size
.
ec_curves() -> [EllipticCurve]
EllipticCurve =
ec_named_curve() | edwards_curve_dh() | edwards_curve_ed()
Can be used to determine which named elliptic curves are supported.
ec_curve(CurveName) -> ExplicitCurve
CurveName = ec_named_curve()
ExplicitCurve = ec_explicit_curve()
Return the defining parameters of a elliptic curve.
sign(Algorithm, DigestType, Msg, Key) -> Signature
Algorithm = pk_sign_verify_algs()
DigestType =
rsa_digest_type() | dss_digest_type() | ecdsa_digest_type()Msg = iodata() | {digest, iodata()}
Key =
rsa_private() |
dss_private() |
[ecdsa_private() | ecdsa_params()] |
[eddsa_private() | eddsa_params()] |
engine_key_ref()Signature = binary()
sign(Algorithm, DigestType, Msg, Key, Options) -> Signature
Algorithm = pk_sign_verify_algs()
DigestType =
rsa_digest_type() |
dss_digest_type() |
ecdsa_digest_type() |
noneMsg = iodata() | {digest, iodata()}
Key =
rsa_private() |
dss_private() |
[ecdsa_private() | ecdsa_params()] |
[eddsa_private() | eddsa_params()] |
engine_key_ref()Options = pk_sign_verify_opts()
Signature = binary()
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.
verify(Algorithm, DigestType, Msg, Signature, Key) -> Result
Algorithm = pk_sign_verify_algs()
DigestType =
rsa_digest_type() |
dss_digest_type() |
ecdsa_digest_type() |
noneMsg = iodata() | {digest, iodata()}
Signature = binary()
Key =
rsa_public() |
dss_public() |
[ecdsa_public() | ecdsa_params()] |
[eddsa_public() | eddsa_params()] |
engine_key_ref()Result = boolean()
verify(Algorithm, DigestType, Msg, Signature, Key, Options) ->
Result
Algorithm = pk_sign_verify_algs()
DigestType =
rsa_digest_type() | dss_digest_type() | ecdsa_digest_type()Msg = iodata() | {digest, iodata()}
Signature = binary()
Key =
rsa_public() |
dss_public() |
[ecdsa_public() | ecdsa_params()] |
[eddsa_public() | eddsa_params()] |
engine_key_ref()Options = pk_sign_verify_opts()
Result = boolean()
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.
Engine API
Functions
privkey_to_pubkey(Type, EnginePrivateKeyRef) -> PublicKey
Type = rsa | dss
EnginePrivateKeyRef = engine_key_ref()
PublicKey = rsa_public() | dss_public()
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.
engine_get_all_methods() -> Result
Result = [engine_method_type()]
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.
engine_load(EngineId, PreCmds, PostCmds) -> Result
EngineId = unicode:chardata()
PreCmds = PostCmds = [engine_cmnd()]
Result =
{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.
engine_load(EngineId, PreCmds, PostCmds, EngineMethods) -> Result
EngineId = unicode:chardata()
PreCmds = PostCmds = [engine_cmnd()]
EngineMethods = [engine_method_type()]
Result =
{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.
engine_unload(Engine) -> Result
Engine = engine_ref()
Result = ok | {error, Reason :: term()}
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.
engine_by_id(EngineId) -> Result
EngineId = unicode:chardata()
Result =
{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.
engine_ctrl_cmd_string(Engine, CmdName, CmdArg) -> Result
Engine = term()
CmdName = CmdArg = unicode:chardata()
Result = ok | {error, Reason :: term()}
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.
engine_ctrl_cmd_string(Engine, CmdName, CmdArg, Optional) ->
Result
Engine = term()
CmdName = CmdArg = unicode:chardata()
Optional = boolean()
Result = ok | {error, Reason :: term()}
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.
engine_add(Engine) -> Result
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.
engine_remove(Engine) -> Result
Engine = engine_ref()
Result = ok | {error, Reason :: term()}
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.
engine_get_id(Engine) -> EngineId
Engine = engine_ref()
EngineId = unicode:chardata()
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.
engine_get_name(Engine) -> EngineName
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.
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.
engine_list() -> Result
Result = [EngineId :: unicode:chardata()]
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.
ensure_engine_loaded(EngineId, LibPath) -> Result
EngineId = LibPath = unicode:chardata()
Result =
{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.
ensure_engine_loaded(EngineId, LibPath, EngineMethods) -> Result
EngineId = LibPath = unicode:chardata()
EngineMethods = [engine_method_type()]
Result =
{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.
ensure_engine_unloaded(Engine) -> Result
Engine = engine_ref()
Result = ok | {error, Reason :: term()}
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.
ensure_engine_unloaded(Engine, EngineMethods) -> Result
Engine = engine_ref()
EngineMethods = [engine_method_type()]
Result = ok | {error, Reason :: term()}
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.
Old API
Functions
block_encrypt(Type :: block_cipher_without_iv(),
Key :: key(),
PlainText :: iodata()) ->
binary() | run_time_error()
Don't use this function for new programs! Use the-new-api.
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.
block_decrypt(Type :: block_cipher_without_iv(),
Key :: key(),
Data :: iodata()) ->
binary() | run_time_error()
Don't use this function for new programs! Use the new api.
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.
Type = block_cipher_with_iv()
AeadType = aead_cipher()
Key = key() | des3_key()
PlainText = iodata()
AAD = IVec = CipherText = CipherTag = binary()
TagLength = 1..16
Error = run_time_error()
Don't use this function for new programs! Use the new api.
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 raise exception error:notsup
in case the chosen Type
is not supported by the underlying libcrypto implementation.
For keylengths, iv-sizes and blocksizes see the User's Guide.
Type = block_cipher_with_iv()
AeadType = aead_cipher()
Key = key() | des3_key()
PlainText = iodata()
AAD = IVec = CipherText = CipherTag = binary()
Error = BadTag | run_time_error()
BadTag = error
Don't use this function for new programs! Use the new api.
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 raise exception error:notsup
in case the chosen Type
is not supported by the underlying libcrypto implementation.
For keylengths, iv-sizes and blocksizes see the User's Guide.
stream_init(Type, Key) -> State | run_time_error()
Type = rc4
Key = iodata()
State = stream_state()
Don't use this function for new programs! Use the new api.
Initializes the state for use in RC4 stream encryption stream_encrypt and stream_decrypt
For keylengths see the User's Guide.
stream_init(Type, Key, IVec) -> State | run_time_error()
Type = stream_cipher()
Key = iodata()
IVec = binary()
State = stream_state()
Don't use this function for new programs! Use the new api.
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 iv-sizes see the User's Guide.
stream_encrypt(State, PlainText) ->
{NewState, CipherText} | run_time_error()
State = stream_state()
PlainText = iodata()
NewState = stream_state()
CipherText = iodata()
Don't use this function for new programs! Use the new api.
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} | run_time_error()
State = stream_state()
CipherText = iodata()
NewState = stream_state()
PlainText = iodata()
Don't use this function for new programs! Use the new api.
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() -> [Support]
Support =
{hashs, Hashs} |
{ciphers, Ciphers} |
{public_keys, PKs} |
{macs, Macs} |
{curves, Curves} |
{rsa_opts, RSAopts}Hashs =
[sha1() |
sha2() |
sha3() |
blake2() |
ripemd160 |
compatibility_only_hash()]Ciphers = [cipher()]
PKs = [rsa | dss | ecdsa | dh | ecdh | ec_gf2m]
Macs = [hmac | cmac | poly1305]
Curves =
[ec_named_curve() | edwards_curve_dh() | edwards_curve_ed()]RSAopts = [rsa_sign_verify_opt() | rsa_opt()]
Don't use this function for new programs! Use supports/1 in the new api.
Can be used to determine which crypto algorithms that are supported by the underlying libcrypto library
See hash_info/1 and cipher_info/1 for information about the hash and cipher algorithms.