/* crypto/aes/aes_cbc.c -*- mode:C; c-file-style: "eay" -*- */

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#ifndef AES_DEBUG

# ifndef NDEBUG

#  define NDEBUG

# endif

#endif

#include <assert.h>

#include <openssl/aes.h>

#include "aes_locl.h"

EXPORT_C void AES_cbc_encrypt(const unsigned char *in, unsigned char *out,

		     const unsigned long length, const AES_KEY *key,

		     unsigned char *ivec, const int enc) {

	unsigned long n;

	unsigned long len = length;

	unsigned char tmp[AES_BLOCK_SIZE];

	const unsigned char *iv = ivec;

	assert(in && out && key && ivec);

	assert((AES_ENCRYPT == enc)||(AES_DECRYPT == enc));

	if (AES_ENCRYPT == enc) {

		while (len >= AES_BLOCK_SIZE) {

			for(n=0; n < AES_BLOCK_SIZE; ++n)

				out[n] = in[n] ^ iv[n];

			AES_encrypt(out, out, key);

			iv = out;

			len -= AES_BLOCK_SIZE;

			in += AES_BLOCK_SIZE;

			out += AES_BLOCK_SIZE;

		}

		if (len) {

			for(n=0; n < len; ++n)

				out[n] = in[n] ^ iv[n];

			for(n=len; n < AES_BLOCK_SIZE; ++n)

				out[n] = iv[n];

			AES_encrypt(out, out, key);

			iv = out;

		}

		memcpy(ivec,iv,AES_BLOCK_SIZE);

	} else if (in != out) {

		while (len >= AES_BLOCK_SIZE) {

			AES_decrypt(in, out, key);

			for(n=0; n < AES_BLOCK_SIZE; ++n)

				out[n] ^= iv[n];

			iv = in;

			len -= AES_BLOCK_SIZE;

			in  += AES_BLOCK_SIZE;

			out += AES_BLOCK_SIZE;

		}

		if (len) {

			AES_decrypt(in,tmp,key);

			for(n=0; n < len; ++n)

				out[n] = tmp[n] ^ iv[n];

			iv = in;

		}

		memcpy(ivec,iv,AES_BLOCK_SIZE);

	} else {

		while (len >= AES_BLOCK_SIZE) {

			memcpy(tmp, in, AES_BLOCK_SIZE);

			AES_decrypt(in, out, key);

			for(n=0; n < AES_BLOCK_SIZE; ++n)

				out[n] ^= ivec[n];

			memcpy(ivec, tmp, AES_BLOCK_SIZE);

			len -= AES_BLOCK_SIZE;

			in += AES_BLOCK_SIZE;

			out += AES_BLOCK_SIZE;

		}

		if (len) {

			memcpy(tmp, in, AES_BLOCK_SIZE);

			AES_decrypt(tmp, out, key);

			for(n=0; n < len; ++n)

				out[n] ^= ivec[n];

			for(n=len; n < AES_BLOCK_SIZE; ++n)

				out[n] = tmp[n];

			memcpy(ivec, tmp, AES_BLOCK_SIZE);

		}

	}

}