1 // SPDX-License-Identifier: BSD-2-Clause 2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis 3 * 4 * LibTomCrypt is a library that provides various cryptographic 5 * algorithms in a highly modular and flexible manner. 6 * 7 * The library is free for all purposes without any express 8 * guarantee it works. 9 */ 10 11 /* The implementation is based on: 12 * chacha-ref.c version 20080118 13 * Public domain from D. J. Bernstein 14 */ 15 16 #include "tomcrypt_private.h" 17 18 #ifdef LTC_CHACHA 19 20 /** 21 Set IV + counter data to the ChaCha state 22 @param st The ChaCha20 state 23 @param iv The IV data to add 24 @param ivlen The length of the IV (must be 8) 25 @param counter 64bit (unsigned) initial counter value 26 @return CRYPT_OK on success 27 */ chacha_ivctr64(chacha_state * st,const unsigned char * iv,unsigned long ivlen,ulong64 counter)28int chacha_ivctr64(chacha_state *st, const unsigned char *iv, unsigned long ivlen, ulong64 counter) 29 { 30 LTC_ARGCHK(st != NULL); 31 LTC_ARGCHK(iv != NULL); 32 /* 64bit IV + 64bit counter */ 33 LTC_ARGCHK(ivlen == 8); 34 35 st->input[12] = (ulong32)(counter & 0xFFFFFFFF); 36 st->input[13] = (ulong32)(counter >> 32); 37 LOAD32L(st->input[14], iv + 0); 38 LOAD32L(st->input[15], iv + 4); 39 st->ksleft = 0; 40 st->ivlen = ivlen; 41 return CRYPT_OK; 42 } 43 44 #endif 45 46 /* ref: $Format:%D$ */ 47 /* git commit: $Format:%H$ */ 48 /* commit time: $Format:%ai$ */ 49