| // SPDX-License-Identifier: BSD-2-Clause |
| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| */ |
| |
| #include "tomcrypt_private.h" |
| |
| #ifdef LTC_CHACHA20POLY1305_MODE |
| |
| /** |
| Terminate a ChaCha20Poly1305 stream |
| @param st The ChaCha20Poly1305 state |
| @param tag [out] The destination for the MAC tag |
| @param taglen [in/out] The length of the MAC tag |
| @return CRYPT_OK on success |
| */ |
| int chacha20poly1305_done(chacha20poly1305_state *st, unsigned char *tag, unsigned long *taglen) |
| { |
| unsigned char padzero[16] = { 0 }; |
| unsigned long padlen; |
| unsigned char buf[16]; |
| int err; |
| |
| LTC_ARGCHK(st != NULL); |
| |
| padlen = 16 - (unsigned long)(st->ctlen % 16); |
| if (padlen < 16) { |
| if ((err = poly1305_process(&st->poly, padzero, padlen)) != CRYPT_OK) return err; |
| } |
| STORE64L(st->aadlen, buf); |
| STORE64L(st->ctlen, buf + 8); |
| if ((err = poly1305_process(&st->poly, buf, 16)) != CRYPT_OK) return err; |
| if ((err = poly1305_done(&st->poly, tag, taglen)) != CRYPT_OK) return err; |
| if ((err = chacha_done(&st->chacha)) != CRYPT_OK) return err; |
| return CRYPT_OK; |
| } |
| |
| #endif |
| |
| /* ref: $Format:%D$ */ |
| /* git commit: $Format:%H$ */ |
| /* commit time: $Format:%ai$ */ |