Mercurial > dropbear
view libtomcrypt/src/encauth/ocb3/ocb3_add_aad.c @ 1552:e46f7f1da56a
CHANGES for 2018.76
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Tue, 27 Feb 2018 22:14:04 +0800 |
parents | 6dba84798cd5 |
children |
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/* 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. */ /** @file ocb3_add_aad.c OCB implementation, add AAD data, by Karel Miko */ #include "tomcrypt.h" #ifdef LTC_OCB3_MODE /** Add one block of AAD data (internal function) @param ocb The OCB state @param aad_block [in] AAD data (block_len size) @return CRYPT_OK if successful */ static int _ocb3_int_aad_add_block(ocb3_state *ocb, const unsigned char *aad_block) { unsigned char tmp[MAXBLOCKSIZE]; int err; /* Offset_i = Offset_{i-1} xor L_{ntz(i)} */ ocb3_int_xor_blocks(ocb->aOffset_current, ocb->aOffset_current, ocb->L_[ocb3_int_ntz(ocb->ablock_index)], ocb->block_len); /* Sum_i = Sum_{i-1} xor ENCIPHER(K, A_i xor Offset_i) */ ocb3_int_xor_blocks(tmp, aad_block, ocb->aOffset_current, ocb->block_len); if ((err = cipher_descriptor[ocb->cipher].ecb_encrypt(tmp, tmp, &ocb->key)) != CRYPT_OK) { return err; } ocb3_int_xor_blocks(ocb->aSum_current, ocb->aSum_current, tmp, ocb->block_len); ocb->ablock_index++; return CRYPT_OK; } /** Add AAD - additional associated data @param ocb The OCB state @param aad The AAD data @param aadlen The size of AAD data (octets) @return CRYPT_OK if successful */ int ocb3_add_aad(ocb3_state *ocb, const unsigned char *aad, unsigned long aadlen) { int err, x, full_blocks, full_blocks_len, last_block_len; unsigned char *data; unsigned long datalen, l; LTC_ARGCHK(ocb != NULL); if (aadlen == 0) return CRYPT_OK; LTC_ARGCHK(aad != NULL); if (ocb->adata_buffer_bytes > 0) { l = ocb->block_len - ocb->adata_buffer_bytes; if (l > aadlen) l = aadlen; XMEMCPY(ocb->adata_buffer+ocb->adata_buffer_bytes, aad, l); ocb->adata_buffer_bytes += l; if (ocb->adata_buffer_bytes == ocb->block_len) { if ((err = _ocb3_int_aad_add_block(ocb, ocb->adata_buffer)) != CRYPT_OK) { return err; } ocb->adata_buffer_bytes = 0; } data = (unsigned char *)aad + l; datalen = aadlen - l; } else { data = (unsigned char *)aad; datalen = aadlen; } if (datalen == 0) return CRYPT_OK; full_blocks = datalen/ocb->block_len; full_blocks_len = full_blocks * ocb->block_len; last_block_len = datalen - full_blocks_len; for (x=0; x<full_blocks; x++) { if ((err = _ocb3_int_aad_add_block(ocb, data+x*ocb->block_len)) != CRYPT_OK) { return err; } } if (last_block_len>0) { XMEMCPY(ocb->adata_buffer, data+full_blocks_len, last_block_len); ocb->adata_buffer_bytes = last_block_len; } return CRYPT_OK; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */