1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
.TH LIBHASHSUM_INIT_SHA3_HASHER 3 libhashsum
.SH NAME
libhashsum_init_sha3_hasher - initialise state for SHA-3 hashing
.SH SYNOPSIS
.nf
#include <libhashsum.h>
\fBstruct libhashsum_hasher\fP {
enum libhashsum_algorithm \fIalgorithm\fP;
const char *\fIalgorithm_string\fP;
size_t \fIinput_block_size\fP;
size_t \fIhash_size\fP;
unsigned char *\fIhash_output\fP;
unsigned char \fIsupports_non_whole_bytes\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);
void (*\fIdestroy\fP)(struct libhashsum_hasher *\fPthis\fP);
union libhashsum_state { /* definition omitted */ } \fIstate\fP;
};
int \fBlibhashsum_init_sha3_hasher\fP(struct libhashsum_hasher *\fIhasher\fP, size_t \fIhashbits\fP);
.fi
.PP
Link with
.I -lhashsum
.IR "-lkeccak" .
.SH DESCRIPTION
The
.B libhashsum_init_sha3_hasher
function initialises
.I *hasher
for hashing using the cryptographic hash function SHA-3,
and stores hash function information and hashing functions
for SHA-3 in
.IR *hasher .
.PP
.I hashbits
shall be the hash size, in bits, which shall be either
224, 256, 384, or 512.
.PP
.I hasher->algorithm
will be set to
.IR LIBHASHSUM_SHA3 .
.PP
.I hasher->algorithm_string
will be set to
.RB \(dq SHA3- \fIhashbits\fP\(dq.
.PP
.I hasher->input_block_size
will be set to the block size, in bytes.
.PP
.I hasher->hash_size
will be set to the hash size, in bytes
.RI ( hashbits/8 ).
.PP
.I hasher->hash_output
will be set to
.IR NULL .
.PP
.I hasher->supports_non_whole_bytes
will be set to 1
to indicate that the
.I *hasher->finalise
and
.I *hasher->finalise_const
functions support non-zero values in their
.I extra_bits
parameter.
.PP
.I hasher->process
will be set to a pointer to the function to call
to feed, and process, data into the hash function.
Its parameter
.I this
shall be set to
.IR hasher .
Its parameter
.I data
parameter shall be set to the buffer of data to
process, and its parameter
.I bytes
shall set to the number of bytes to process from
.IR data .
.I *hasher->process
will return the number of bytes processed, which
will be a multiple of
.IR hasher->input_block_size
no greater than
.IR bytes .
.PP
.I hasher->finalise_const
will be set to a pointer to the function to call
once the entire text being hashed has been loaded,
and to get the hash of the text. It's parameter
.I this
shall be set to
.IR hasher .
Its parameter
.I data
shall be set to the beginning of any yet unprocessed
data, and its parameter
.I bytes
shall be set to the number of bytes to process from
.IR data .
Its parameter
.I extra_bits
shall be set to the number of bits to process from
the lower bits of the incomplete byte
.IR data[bytes] .
The
.I *hasher->finalise_const
function will return 0 upon successful completion,
and set
.I hasher->hash_output
to a pointer to a buffer in
.I hasher->state
containing the binary hash of the processed data.
Otherwise, the function will return -1, and set
.I errno
to indicate the error. The function will failure
if:
.RS
.TP
.B EINVAL
.I extra_bits
is 8 or greater.
.RE
.PP
.I hasher->finalise
will be set to the pointer to a function that
is an alternative to
.I *hasher->finalise_const
that can support zero-copy provided that the
buffer input as the argument
.I data
is sufficiently large. The
.I *hasher->finalise
function may rewrite
.I data
and shall is does not safe to use for multiple
hashers (if the same text is hashed using multiple
hashers,
.I *hasher->finalise_const
must be used). The
function's parameter
.I size
shall be set to the size of the buffer
.IR data .
.I *hasher->finalise
is otherwise identical to
.IR *hasher->finalise_const .
.PP
.I hasher->destroy
will be set to a pointer to a function to to
call, with
.I hasher
as the argument, deallocate dynamically
allocated data, which may invalidate any
pointer in
.IR *hasher .
.PP
.I hasher->state
will be initialised, it shall be treated as
internal to the library's implementation, and
may change between versions.
.PP
.I hasher
must not be
.IR NULL .
.SH RETURN VALUE
Upon successful completion, the
.B libhashsum_init_sha3_hasher
function returns 0. Otherwise,
the function returns -1 and sets
.I errno
to indicate the error. If -1
is returned, the state of
.I *hasher
is undefined.
.SH ERRORS
The
.B libhashsum_init_sha3_hasher
function fails if:
.TP
.B ENOSYS
Support was excluded at compile time.
.TP
.B ENOMEM
Insufficient memory available.
.TP
.B EINVAL
.I hashbits
is neither 224, 245, 384, nor 512.
.SH HISTORY
libhashsum 1.0.
.SH NOTES
.IR "libhashsum_init_sha3_hasher(hasher, 224)" ,
.IR "libhashsum_init_sha3_hasher(hasher, 256)" ,
.IR "libhashsum_init_sha3_hasher(hasher, 384)" ,
and
.I libhashsum_init_sha3_hasher(hasher, 512)
are equivalent to
.IR libhashsum_init_sha3_224_hasher(hasher) ,
.IR libhashsum_init_sha3_256_hasher(hasher) ,
.IR libhashsum_init_sha3_384_hasher(hasher) ,
and
.I libhashsum_init_sha3_512_hasher(hasher)
respectively.
.SH SEE ALSO
.BR libhashsum (7),
.BR libhashsum_init_sha3_224_hasher (3),
.BR libhashsum_init_sha3_256_hasher (3),
.BR libhashsum_init_sha3_384_hasher (3),
.BR libhashsum_init_sha3_512_hasher (3)
|
