diff options
Diffstat (limited to 'libhashsum_init_hasher.3')
| -rw-r--r-- | libhashsum_init_hasher.3 | 75 |
1 files changed, 74 insertions, 1 deletions
diff --git a/libhashsum_init_hasher.3 b/libhashsum_init_hasher.3 index a61b00e..5bb2b62 100644 --- a/libhashsum_init_hasher.3 +++ b/libhashsum_init_hasher.3 @@ -15,6 +15,8 @@ libhashsum_init_hasher - initialise state for hashing size_t \fIhash_size\fP; unsigned char *\fIhash_output\fP; unsigned char \fIsupports_non_whole_bytes\fP; + unsigned char \fIstandard_partial_byte_input_encoding\fP; + unsigned char \fIstandard_partial_byte_output_encoding\fP; size_t (*\fIprocess\fP)(struct libhashsum_hasher *\fPthis\fP, const void *\fPdata\fP, size_t \fPbytes\fP); int (*\fIfinalise_const\fP)(struct libhashsum_hasher *\fPthis\fP, const void *\fPdata\fP, size_t \fPbytes\fP, unsigned \fPextra_bits\fP); int (*\fIfinalise\fP)(struct libhashsum_hasher *\fPthis\fP, void *\fPdata\fP, size_t \fPbytes\fP, unsigned \fPextra_bits\fP, size_t \fPsize\fP); @@ -239,7 +241,7 @@ Selects BLAKE2s (BLAKE2). See for more information. .TP .B LIBHASHSUM_BLAKE2B -Selects BLAKE2b (BLAKE). See +Selects BLAKE2b (BLAKE2). See .BR libhashsum_init_blake2b_hasher (3) for more information. .PP @@ -487,6 +489,77 @@ is unrecognised or unsupported. .B ENOMEM Insufficient memory available. +.SH EXTENDED DESCRIPTION +libhashsum has normalises the all implemented hash +functions to always use the least significant bits +in non-whole octets, however each hash function has +its unstandarded. To make it easier to create an +application the use the same encoding of partial +octets as other application using any particular +hash function, +.B struct libhashsum_hasher +contains two fields: +.I standard_partial_byte_input_encoding +and +.IR standard_partial_byte_output_encoding ; +which are merely informtional. They are not set to +specify how libhashsum expects and encodes non-whole +octets, but rather specify how partial bytes are +encoded in the reference implementation or +specification of a hash function. +.PP +If the hash function does not support non-whole +input octets, +.I this->standard_partial_byte_input_encoding +will be set to +.IR LIBHASHSUM_UNSUPPORTED . +.PP +If the hash function supports non-whole input +octets, and uses the least significant bits +in its standard, which is the same behaviour +as implemented by libhashsum, +.I this->standard_partial_byte_input_encoding +will be set to +.IR LIBHASHSUM_LEAST_SIGNIFICANT . +.PP +If the hash function supports non-whole input +octets, and uses the most significant bits +in its standard, which is the opposite behaviour +of what is implemented by libhashsum, +.I this->standard_partial_byte_input_encoding +will be set to +.IR LIBHASHSUM_MOST_SIGNIFICANT . +This means that the partial octet must be +reverted to convert between the libhashsum's +encoding and the hash function's standard's +encoding. +.PP +If the hash function does not support non-whole +octet hashes, +.I this->standard_partial_byte_output_encoding +will be set to +.IR LIBHASHSUM_UNSUPPORTED . +.PP +If the hash function supports non-whole octet +hashes, and uses the least significant bits +in its standard, which is the same behaviour +as implemented by libhashsum, +.I this->standard_partial_byte_output_encoding +will be set to +.IR LIBHASHSUM_LEAST_SIGNIFICANT . +.PP +If the hash function supports non-whole octet +hashes, and uses the most significant bits +in its standard, which is the opposite behaviour +of what is implemented by libhashsum, +.I this->standard_partial_byte_output_encoding +will be set to +.IR LIBHASHSUM_MOST_SIGNIFICANT . +This means that the last octet, if partial, +must be reverted to convert between the +libhashsum's encoding and the hash function's +standard's encoding. + .SH HISTORY libhashsum 1.0. |