uint8_t tmp[ctx->blocksize_B];
memcpy(tmp, block, ctx->blocksize_B);
bcal_cipher_dec(block, &(ctx->cctx));
memxor(block, ctx->prev_block, ctx->blocksize_B);
memcpy(ctx->prev_block, tmp, ctx->blocksize_B);
}
uint8_t tmp[ctx->blocksize_B];
memcpy(tmp, block, ctx->blocksize_B);
bcal_cipher_dec(block, &(ctx->cctx));
memxor(block, ctx->prev_block, ctx->blocksize_B);
memcpy(ctx->prev_block, tmp, ctx->blocksize_B);
}