NAME
libkeccak_spec_check - Validate hashing parameters
SYNOPSIS
#include <libkeccak.h> int libkeccak_spec_check(const struct libkeccak_spec *spec);
Link with -lkeccak.
DESCRIPTION
The libkeccak_spec_check() function validates the parameters of *spec, so that unusable configurations can be detected. It is recommended to call this function after calling libkeccak_spec_sha3(3), libkeccak_spec_cshake(3), libkeccak_spec_rawshake(3), libkeccak_spec_shake(3), or, especially, after settings the parameters manually for Keccak hashing.
struct libkeccak_spec {
long int bitrate; /* bitrate (in bits) */
long int capacity; /* capacity (in bits) */
long int output; /* output size (in bits) */
};
RETURN VALUES
The libkeccak_spec_check() function returns 0 if the settings are usable. Otherwise it will return one of the following constants.
- LIBKECCAK_SPEC_ERROR_BITRATE_NONPOSITIVE
-
The specified bitrate was non-positive.
- LIBKECCAK_SPEC_ERROR_BITRATE_MOD_8
-
The specified bitrate was not equivalent to 0 modulus 8, that is, it was not in whole bytes.
- LIBKECCAK_SPEC_ERROR_CAPACITY_NONPOSITIVE
-
The specified capacity was non-positive.
- LIBKECCAK_SPEC_ERROR_CAPACITY_MOD_8
-
The specified capacity was not equivalent to 0 modulus 8, that is, it was not in whole bytes.
- LIBKECCAK_SPEC_ERROR_OUTPUT_NONPOSITIVE
-
The specified output size was non-positive.
- LIBKECCAK_SPEC_ERROR_STATE_TOO_LARGE
-
The state size, that is the sum of the bitrate and the capacity, exceeded the supported limit (currently at 1600 bits.)
- LIBKECCAK_SPEC_ERROR_STATE_MOD_25
-
The state size, that is the sum of the bitrate and the capacity, in bits, was not equivalent to 0 modulus 25. Meaning the state size cannot cover all lanes equivalently.
- LIBKECCAK_SPEC_ERROR_WORD_NON_2_POTENT
-
The word size, that is the state size divided by 25, is not a power of 2.
- LIBKECCAK_SPEC_ERROR_WORD_MOD_8
-
The word size, that is the state size divided by 25, is not quivalent to 0 modulus 8, that is, it is not in whole bytes.
Note that there may be more than one error. Only the first detected is returned.
ERRORS
The libkeccak_spec_check() function cannot fail.
SEE ALSO
libkeccak_spec_sha3(3), libkeccak_spec_cshake(3), libkeccak_spec_rawshake(3), libkeccak_spec_shake(3), libkeccak_generalised_spec_initialise(3), libkeccak_state_initialise(3), libkeccak_hmac_initialise(3)