lib_3des.c

老外写的加密库cryptlib(版本3.1)

/****************************************************************************
*																			*
*					cryptlib Triple DES Encryption Routines					*
*						Copyright Peter Gutmann 1994-2003					*
*																			*
****************************************************************************/

#include <stdlib.h>
#if defined( INC_ALL )
  #include "crypt.h"
  #include "des.h"
  #include "context.h"
  #include "libs.h"
#elif defined( INC_CHILD )
  #include "../crypt.h"
  #include "../crypt/des.h"
  #include "../misc/context.h"
  #include "../libs/libs.h"
#else
  #include "crypt.h"
  #include "crypt/des.h"
  #include "misc/context.h"
  #include "libs/libs.h"
#endif /* Compiler-specific includes */

/* The DES block size */

#define DES_BLOCKSIZE	8

#if defined( INC_ALL )
  #include "testdes.h"
#elif defined( INC_CHILD )
  #include "../crypt/testdes.h"
#else
  #include "crypt/testdes.h"
#endif /* Compiler-specific includes */

/* A structure to hold the keyscheduled DES keys */

typedef struct {
	Key_schedule desKey1;			/* The first DES key */
	Key_schedule desKey2;			/* The second DES key */
	Key_schedule desKey3;			/* The third DES key */
	} DES3_KEY;

/* The size of the keyscheduled DES and 3DES keys */

#define DES_KEYSIZE		sizeof( Key_schedule )
#define DES3_KEYSIZE	sizeof( DES3_KEY )

/****************************************************************************
*																			*
*								3DES Self-test Routines						*
*																			*
****************************************************************************/

/* Test the DES implementation against the test vectors given in NBS Special
   Publication 800-20, 1999 (which are actually the same as 500-20, 1980,
   since they require that K1 = K2 = K3, but we do it anyway so we can claim
   compliance) */

static int des3TestLoop( const DES_TEST *testData, int iterations )
	{
	BYTE temp[ DES_BLOCKSIZE ];
	BYTE key1[ DES_KEYSIZE ], key2[ DES_KEYSIZE ], key3[ DES_KEYSIZE ];
	int i;

	for( i = 0; i < iterations; i++ )
		{
		memcpy( temp, testData[ i ].plaintext, DES_BLOCKSIZE );

		/* Since the self-test uses weak keys, we have to explicitly use the
		   non-parity-checking key schedule function */
		des_set_key_unchecked( ( C_Block * ) testData[ i ].key,
							   *( ( Key_schedule * ) key1 ) );
		des_set_key_unchecked( ( C_Block * ) testData[ i ].key,
							   *( ( Key_schedule * ) key2 ) );
		des_set_key_unchecked( ( C_Block * ) testData[ i ].key,
							   *( ( Key_schedule * ) key3 ) );
		des_ecb3_encrypt( ( C_Block * ) temp, ( C_Block * ) temp,
						  *( ( Key_schedule * ) key1 ), 
						  *( ( Key_schedule * ) key2 ), 
						  *( ( Key_schedule * ) key3 ), DES_ENCRYPT );
		if( memcmp( testData[ i ].ciphertext, temp, DES_BLOCKSIZE ) )
			return( CRYPT_ERROR );
		}

	return( CRYPT_OK );
	}

int des3SelfTest( void )
	{
	int status = CRYPT_OK;

	/* Check the 3DES test vectors.  Note that we don't perform the RS test, 
	   since it's valid only for single DES */
	if( ( des3TestLoop( testIP, sizeof( testIP ) / sizeof( DES_TEST ) ) != CRYPT_OK ) || \
		( des3TestLoop( testVP, sizeof( testVP ) / sizeof( DES_TEST ) ) != CRYPT_OK ) || \
		( des3TestLoop( testKP, sizeof( testKP ) / sizeof( DES_TEST ) ) != CRYPT_OK ) || \
		( des3TestLoop( testDP, sizeof( testDP ) / sizeof( DES_TEST ) ) != CRYPT_OK ) || \
		( des3TestLoop( testSB, sizeof( testSB ) / sizeof( DES_TEST ) ) != CRYPT_OK ) )
		status = CRYPT_ERROR;

	return( status );
	}

/****************************************************************************
*																			*
*								Control Routines							*
*																			*
****************************************************************************/

/* Return context subtype-specific information */

int des3GetInfo( const CAPABILITY_INFO_TYPE type, 
				 void *varParam, const int constParam )
	{
	if( type == CAPABILITY_INFO_STATESIZE )
		return( DES3_KEYSIZE );

	return( getInfo( type, varParam, constParam ) );
	}

/****************************************************************************
*																			*
*							3DES En/Decryption Routines						*
*																			*
****************************************************************************/

/* Encrypt/decrypt data in ECB mode */

int des3EncryptECB( CONTEXT_INFO *contextInfoPtr, BYTE *buffer, int noBytes )
	{
	CONV_INFO *convInfo = contextInfoPtr->ctxConv;
	DES3_KEY *des3Key = ( DES3_KEY * ) convInfo->key;
	int blockCount = noBytes / DES_BLOCKSIZE;

	while( blockCount-- )
		{
		/* Encrypt a block of data */
		des_ecb3_encrypt( ( C_Block * ) buffer, ( C_Block * ) buffer,
						  des3Key->desKey1, des3Key->desKey2,
						  des3Key->desKey3, DES_ENCRYPT );

		/* Move on to next block of data */
		buffer += DES_BLOCKSIZE;
		}

	return( CRYPT_OK );
	}

int des3DecryptECB( CONTEXT_INFO *contextInfoPtr, BYTE *buffer, int noBytes )
	{
	CONV_INFO *convInfo = contextInfoPtr->ctxConv;
	DES3_KEY *des3Key = ( DES3_KEY * ) convInfo->key;
	int blockCount = noBytes / DES_BLOCKSIZE;

	while( blockCount-- )
		{
		/* Decrypt a block of data */
		des_ecb3_encrypt( ( C_Block * ) buffer, ( C_Block * ) buffer,
						  des3Key->desKey1, des3Key->desKey2,
						  des3Key->desKey3, DES_DECRYPT );

		/* Move on to next block of data */
		buffer += DES_BLOCKSIZE;
		}

	return( CRYPT_OK );
	}

/* Encrypt/decrypt data in CBC mode */

int des3EncryptCBC( CONTEXT_INFO *contextInfoPtr, BYTE *buffer, int noBytes )
	{
	CONV_INFO *convInfo = contextInfoPtr->ctxConv;
	DES3_KEY *des3Key = ( DES3_KEY * ) convInfo->key;

	des_ede3_cbc_encrypt( buffer, buffer, noBytes,
						  des3Key->desKey1, des3Key->desKey2, des3Key->desKey3,
						  ( C_Block * ) convInfo->currentIV, DES_ENCRYPT );

	return( CRYPT_OK );
	}

int des3DecryptCBC( CONTEXT_INFO *contextInfoPtr, BYTE *buffer, int noBytes )
	{
	CONV_INFO *convInfo = contextInfoPtr->ctxConv;
	DES3_KEY *des3Key = ( DES3_KEY * ) convInfo->key;

	des_ede3_cbc_encrypt( buffer, buffer, noBytes,
						  des3Key->desKey1, des3Key->desKey2, des3Key->desKey3,
						  ( C_Block * ) convInfo->currentIV, DES_DECRYPT );

	return( CRYPT_OK );
	}

/* Encrypt/decrypt data in CFB mode */

int des3EncryptCFB( CONTEXT_INFO *contextInfoPtr, BYTE *buffer, int noBytes )
	{
	CONV_INFO *convInfo = contextInfoPtr->ctxConv;
	DES3_KEY *des3Key = ( DES3_KEY * ) convInfo->key;
	int i, ivCount = convInfo->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 ] ^= convInfo->currentIV[ i + ivCount ];
		memcpy( convInfo->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 * ) convInfo->currentIV,
						  ( C_Block * ) convInfo->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 ] ^= convInfo->currentIV[ i ];

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

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