lib_3des.c

提供了很多种加密算法和CA认证及相关服务如CMP、OCSP等的开发

		bytesToUse = DES_BLOCKSIZE - ivCount;
		if( noBytes < bytesToUse )
			bytesToUse = noBytes;

		/* Encrypt the data */
		for( i = 0; i < bytesToUse; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i + ivCount ];
		memcpy( cryptInfo->ctxConv.currentIV + ivCount, buffer, bytesToUse );

		/* Adjust the byte count and buffer position */
		noBytes -= bytesToUse;
		buffer += bytesToUse;
		ivCount += bytesToUse;
		}

	while( noBytes )
		{
		ivCount = ( noBytes > DES_BLOCKSIZE ) ? DES_BLOCKSIZE : noBytes;

		/* Encrypt the IV */
		des_ecb3_encrypt( ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  des3Key->desKey1, des3Key->desKey2,
						  des3Key->desKey3, DES_ENCRYPT );

		/* XOR the buffer contents with the encrypted IV */
		for( i = 0; i < ivCount; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i ];

		/* Shift the ciphertext into the IV */
		memcpy( cryptInfo->ctxConv.currentIV, buffer, ivCount );

		/* Move on to next block of data */
		noBytes -= ivCount;
		buffer += ivCount;
		}

	/* Remember how much of the IV is still available for use */
	cryptInfo->ctxConv.ivCount = ( ivCount % DES_BLOCKSIZE );

	return( CRYPT_OK );
	}

/* Decrypt data in CFB mode.  Note that the transformation can be made
   faster (but less clear) with temp = buffer, buffer ^= iv, iv = temp
   all in one loop */

int des3DecryptCFB( CRYPT_INFO *cryptInfo, BYTE *buffer, int noBytes )
	{
	DES3_KEY *des3Key = ( DES3_KEY * ) cryptInfo->ctxConv.key;
	BYTE temp[ DES_BLOCKSIZE ];
	int i, ivCount = cryptInfo->ctxConv.ivCount;

	/* If there's any encrypted material left in the IV, use it now */
	if( ivCount )
		{
		int bytesToUse;

		/* Find out how much material left in the encrypted IV we can use */
		bytesToUse = DES_BLOCKSIZE - ivCount;
		if( noBytes < bytesToUse )
			bytesToUse = noBytes;

		/* Decrypt the data */
		memcpy( temp, buffer, bytesToUse );
		for( i = 0; i < bytesToUse; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i + ivCount ];
		memcpy( cryptInfo->ctxConv.currentIV + ivCount, temp, bytesToUse );

		/* Adjust the byte count and buffer position */
		noBytes -= bytesToUse;
		buffer += bytesToUse;
		ivCount += bytesToUse;
		}

	while( noBytes )
		{
		ivCount = ( noBytes > DES_BLOCKSIZE ) ? DES_BLOCKSIZE : noBytes;

		/* Encrypt the IV */
		des_ecb3_encrypt( ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  des3Key->desKey1, des3Key->desKey2,
						  des3Key->desKey3, DES_ENCRYPT );

		/* Save the ciphertext */
		memcpy( temp, buffer, ivCount );

		/* XOR the buffer contents with the encrypted IV */
		for( i = 0; i < ivCount; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i ];

		/* Shift the ciphertext into the IV */
		memcpy( cryptInfo->ctxConv.currentIV, temp, ivCount );

		/* Move on to next block of data */
		noBytes -= ivCount;
		buffer += ivCount;
		}

	/* Remember how much of the IV is still available for use */
	cryptInfo->ctxConv.ivCount = ( ivCount % DES_BLOCKSIZE );

	/* Clear the temporary buffer */
	zeroise( temp, DES_BLOCKSIZE );

	return( CRYPT_OK );
	}

/* Encrypt/decrypt data in OFB mode */

int des3EncryptOFB( CRYPT_INFO *cryptInfo, BYTE *buffer, int noBytes )
	{
	DES3_KEY *des3Key = ( DES3_KEY * ) cryptInfo->ctxConv.key;
	int i, ivCount = cryptInfo->ctxConv.ivCount;

	/* If there's any encrypted material left in the IV, use it now */
	if( ivCount )
		{
		int bytesToUse;

		/* Find out how much material left in the encrypted IV we can use */
		bytesToUse = DES_BLOCKSIZE - ivCount;
		if( noBytes < bytesToUse )
			bytesToUse = noBytes;

		/* Encrypt the data */
		for( i = 0; i < bytesToUse; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i + ivCount ];

		/* Adjust the byte count and buffer position */
		noBytes -= bytesToUse;
		buffer += bytesToUse;
		ivCount += bytesToUse;
		}

	while( noBytes )
		{
		ivCount = ( noBytes > DES_BLOCKSIZE ) ? DES_BLOCKSIZE : noBytes;

		/* Encrypt the IV */
		des_ecb3_encrypt( ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  des3Key->desKey1, des3Key->desKey2,
						  des3Key->desKey3, DES_ENCRYPT );

		/* XOR the buffer contents with the encrypted IV */
		for( i = 0; i < ivCount; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i ];

		/* Move on to next block of data */
		noBytes -= ivCount;
		buffer += ivCount;
		}

	/* Remember how much of the IV is still available for use */
	cryptInfo->ctxConv.ivCount = ( ivCount % DES_BLOCKSIZE );

	return( CRYPT_OK );
	}

/* Decrypt data in OFB mode */

int des3DecryptOFB( CRYPT_INFO *cryptInfo, BYTE *buffer, int noBytes )
	{
	DES3_KEY *des3Key = ( DES3_KEY * ) cryptInfo->ctxConv.key;
	int i, ivCount = cryptInfo->ctxConv.ivCount;

	/* If there's any encrypted material left in the IV, use it now */
	if( ivCount )
		{
		int bytesToUse;

		/* Find out how much material left in the encrypted IV we can use */
		bytesToUse = DES_BLOCKSIZE - ivCount;
		if( noBytes < bytesToUse )
			bytesToUse = noBytes;

		/* Decrypt the data */
		for( i = 0; i < bytesToUse; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i + ivCount ];

		/* Adjust the byte count and buffer position */
		noBytes -= bytesToUse;
		buffer += bytesToUse;
		ivCount += bytesToUse;
		}

	while( noBytes )
		{
		ivCount = ( noBytes > DES_BLOCKSIZE ) ? DES_BLOCKSIZE : noBytes;

		/* Encrypt the IV */
		des_ecb3_encrypt( ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  ( C_Block * ) cryptInfo->ctxConv.currentIV,
						  des3Key->desKey1, des3Key->desKey2,
						  des3Key->desKey3, DES_ENCRYPT );

		/* XOR the buffer contents with the encrypted IV */
		for( i = 0; i < ivCount; i++ )
			buffer[ i ] ^= cryptInfo->ctxConv.currentIV[ i ];

		/* Move on to next block of data */
		noBytes -= ivCount;
		buffer += ivCount;
		}

	/* Remember how much of the IV is still available for use */
	cryptInfo->ctxConv.ivCount = ( ivCount % DES_BLOCKSIZE );

	return( CRYPT_OK );
	}

/****************************************************************************
*																			*
*							3DES Key Management Routines						*
*																			*
****************************************************************************/

/* Key schedule two/three DES keys */

int des3InitKey( CRYPT_INFO *cryptInfo, const void *key, const int keyLength )
	{
	DES3_KEY *des3Key = ( DES3_KEY * ) cryptInfo->ctxConv.key;
	BOOLEAN useEDE = FALSE;

	/* Copy the key to internal storage */
	if( cryptInfo->ctxConv.userKey != key )
		memcpy( cryptInfo->ctxConv.userKey, key, keyLength );
	cryptInfo->ctxConv.userKeyLength = keyLength;

	/* Check the key size.  This gets a bit complicated because although we
	   follow X9.52 and default to three-key triple DES, we'll often be
	   passed a 128 (112)-bit key which was common in older designs.  If this
	   happens we take the 112-bit key and repeat the first 56 bits to create
	   a 168-bit key.  X9.52 says that if the caller wants EDE behaviour they
	   have to set it up themselves using a full 168-bit key, but this will
	   cause problems for people using the high-level functions which don't
	   allow this level of control, so if we're passed a 112-bit key we just
	   expand it out to 168 bits to get two-key EDE */
	if( keyLength <= bitsToBytes( 64 * 2 ) )
		useEDE = TRUE;	/* Only 112 bits of key, force EDE mode */

	/* Call the libdes key schedule code.  Returns with -1 if the key parity
	   is wrong (which never occurs since we force the correct parity) or -2
	   if a weak key is used */
	des_set_odd_parity( ( C_Block * ) cryptInfo->ctxConv.userKey );
	if( key_sched( ( des_cblock * ) cryptInfo->ctxConv.userKey,
				   des3Key->desKey1 ) )
		return( CRYPT_ARGERROR_STR1 );
	des_set_odd_parity( ( C_Block * ) ( ( BYTE * ) cryptInfo->ctxConv.userKey + bitsToBytes( 64 ) ) );
	if( key_sched( ( des_cblock * ) ( ( BYTE * ) cryptInfo->ctxConv.userKey + bitsToBytes( 64 ) ),
				   des3Key->desKey2 ) )
		return( CRYPT_ARGERROR_STR1 );
	if( useEDE )
		/* Rather than performing another key schedule, we just copy the first
		   scheduled key into the third one */
		memcpy( des3Key->desKey3, des3Key->desKey1, DES_KEYSIZE );
	else
		{
		des_set_odd_parity( ( C_Block * ) ( ( BYTE * ) cryptInfo->ctxConv.userKey + bitsToBytes( 128 ) ) );
		if( key_sched( ( des_cblock * ) ( ( BYTE * ) cryptInfo->ctxConv.userKey + bitsToBytes( 128 ) ),
					   des3Key->desKey3 ) )
			return( CRYPT_ARGERROR_STR1 );
		}

	return( CRYPT_OK );
	}