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Diffstat (limited to 'libkeccak_fast_update.3')
| -rw-r--r-- | libkeccak_fast_update.3 | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/libkeccak_fast_update.3 b/libkeccak_fast_update.3 new file mode 100644 index 0000000..3398984 --- /dev/null +++ b/libkeccak_fast_update.3 @@ -0,0 +1,90 @@ +.TH LIBKECCAK_FAST_UPDATE 3 LIBKECCAK +.SH NAME +libkeccak_fast_update - Partially hash a message without erasure +.SH SYNOPSIS +.nf +#include <libkeccak.h> + +int libkeccak_fast_update(libkeccak_state_t *\fIstate\fP, const void *\fImsg\fP, size_t \fImsglen\fP); +.fi +.PP +Link with +.IR -lkeccak . +.SH DESCRIPTION +The +.BR libkeccak_fast_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_fast_update () +function may reallocate the state's message chunk buffer. +When doing so, it attempts to do so as quickly as possible, +rather than ensuring that the information in the old +allocation is securely removed if a new allocation is required. +.SH RETURN VALUES +The +.BR libkeccak_fast_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_fast_update () +function may fail for any reason specified by the function +.BR realloc (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. +.PP +.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_fast_update(&state, chunk, (size_t)len) < 0) + goto fail; +} +if (libkeccak_fast_digest(&state, NULL, 0, 0, \(dq\(dq, binhash) < 0) + goto fail; + +libkeccak_behex_lower(hexhash, binhash, sizeof(binhash)); +printf(\(dq%s\en\(dq, hexhash); +libkeccak_state_fast_destroy(&state); +.fi +.SH SEE ALSO +.BR libkeccak_state_initialise (3), +.BR libkeccak_update (3), +.BR libkeccak_fast_digest (3), +.BR libkeccak_digest (3) |