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author | Mattias Andrée <maandree@kth.se> | 2019-02-09 21:56:53 +0100 |
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committer | Mattias Andrée <maandree@kth.se> | 2019-02-09 21:56:53 +0100 |
commit | 7085817a3d356f7c3240fe1d616a5b1f1b56e38a (patch) | |
tree | 9bfebc7c3330d99410cc8a73af3ee2f21e386be0 /man3/libkeccak_update.3 | |
parent | Remove texinfo file (it was truncated anyhow for some reason) (diff) | |
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Fix makefile add add OSCONFIGFILE
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to 'man3/libkeccak_update.3')
-rw-r--r-- | man3/libkeccak_update.3 | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/man3/libkeccak_update.3 b/man3/libkeccak_update.3 new file mode 100644 index 0000000..d83f74b --- /dev/null +++ b/man3/libkeccak_update.3 @@ -0,0 +1,95 @@ +.TH LIBKECCAK_UPDATE 3 LIBKECCAK +.SH NAME +libkeccak_update - Partially hash a message with erasure +.SH SYNOPSIS +.LP +.nf +#include <libkeccak.h> +.P +int +libkeccak_update(libkeccak_state_t *\fIstate\fP, const char *\fImsg\fP, + size_t \fImsglen\fP); +.fi +.P +Link with +.IR -lkeccak . +.SH DESCRIPTION +The +.BR libkeccak_update () +function continues (or starts) hashing a message. +The current state of the hashing is stored in +.IR *state , +and will be updated. The message specified by the +.I msg +parameter with the byte-size specified by the +.I msglen +parameter, will be hashed. +.PP +The +.BR libkeccak_update () +function may reallocate the state's message chunk buffer. +When doing so, it attempts to do so as securely as possible, +rather than as fast as possible. +.SH RETURN VALUES +The +.BR libkeccak_update () +function returns 0 upon successful completion. On error, +-1 is returned and +.I errno +is set to describe the error. +.SH ERRORS +The +.BR libkeccak_update () +function may fail for any reason specified by the function +.BR malloc (3). +.SH NOTES +Neither parameter by be +.I NULL +or 0. +.SH EXAMPLE +This example calculates the Keccak[b = 1024, c = 576, n = 256] +hash of the input from stdin, and prints the hash, in hexadecimal +form, to stdout. +.LP +.nf +libkeccak_state_t state; +libkeccak_spec_t spec; +char binhash[256 / 8]; +char hexhash[256 / 8 * 2 + 1]; +char chunk[4 << 10]; +ssize_t len; + +spec.bitrate = 1024; +spec.capacity = 576; +spec.output = 256; +if (libkeccak_state_initialise(&state, &spec) < 0) + goto fail; + +for (;;) { + len = read(STDIN_FILENO, chunk, sizeof(chunk)); + + if ((len < 0) && (errno == EINTR)) + continue; + if (len < 0) + goto fail; + if (len == 0) + break; + + if (libkeccak_update(&state, chunk, (size_t)len) < 0) + goto fail; +} +if (libkeccak_digest(&state, NULL, 0, 0, "", binhash) < 0) + goto fail; + +libkeccak_behex_lower(hexhash, binhash, sizeof(binhash)); +printf("%s\\n", hexhash); +libkeccak_state_destroy(&state); +.fi +.SH SEE ALSO +.BR libkeccak_state_initialise (3), +.BR libkeccak_fast_update (3), +.BR libkeccak_fast_digest (3), +.BR libkeccak_digest (3) +.SH BUGS +Please report bugs to https://github.com/maandree/libkeccak/issues or to +maandree@kth.se |