The most important predicates to compute hashes are:
- [det]crypto_data_hash(+Data,
-Hash, +Options)
- Hash is the hash of Data. The conversion is
controlled by Options:
- algorithm(+Algorithm)
- One of
md5 (insecure), sha1 (insecure), ripemd160,
sha224, sha256, sha384, sha512, sha3_224, sha3_256,
sha3_384, sha3_512, blake2s256 or blake2b512.
The BLAKE digest algorithms require OpenSSL 1.1.0 or greater, and the
SHA-3 algorithms require OpenSSL 1.1.1 or greater. The default is a
cryptographically secure algorithm. If you specify a variable, then that
variable is unified with the algorithm that was used.
- encoding(+Encoding)
- If Data is a sequence of character codes, this must be
translated into a sequence of bytes, because that is what the
hashing requires. The default encoding is
utf8. The other
meaningful value is octet, claiming that Data
contains raw bytes.
- hmac(+Key)
- If this option is specified, a hash-based message authentication code
(HMAC) is computed, using the specified Key which is either
an atom, string or list of bytes. Any of the available digest
algorithms can be used with this option. The cryptographic strength of
the HMAC depends on that of the chosen algorithm and also on the key.
This option requires OpenSSL 1.1.0 or greater.
| Data | is either an atom, string or code-list |
| Hash | is an atom that represents the hash in
hexadecimal encoding. |
- See also
- - hex_bytes/2 for conversion
between hexadecimal encoding and lists of bytes.
- crypto_password_hash/2
for the important use case of passwords.
- [det]crypto_file_hash(+File,
-Hash, +Options)
- True if Hash is the hash of the content of File.
For Options, see crypto_data_hash/3.