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data-lite-c/Sources/DataLiteC/libtomcrypt/stream/salsa20/salsa20_ivctr64.c

39 lines
1.0 KiB
C

/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* The implementation is based on:
* "Salsa20 specification", http://cr.yp.to/snuffle/spec.pdf
* and salsa20-ref.c version 20051118
* Public domain from D. J. Bernstein
*/
#include "tomcrypt_private.h"
#ifdef LTC_SALSA20
/**
Set IV + counter data to the Salsa20 state
@param st The Salsa20 state
@param iv The IV data to add
@param ivlen The length of the IV (must be 8)
@param counter 64bit (unsigned) initial counter value
@return CRYPT_OK on success
*/
int salsa20_ivctr64(salsa20_state *st, const unsigned char *iv, unsigned long ivlen, ulong64 counter)
{
LTC_ARGCHK(st != NULL);
LTC_ARGCHK(iv != NULL);
/* Salsa20: 64-bit IV (nonce) + 64-bit counter */
LTC_ARGCHK(ivlen == 8);
LOAD32L(st->input[6], iv + 0);
LOAD32L(st->input[7], iv + 4);
st->input[8] = (ulong32)(counter & 0xFFFFFFFF);
st->input[9] = (ulong32)(counter >> 32);
st->ksleft = 0;
st->ivlen = ivlen;
return CRYPT_OK;
}
#endif