ctx_3des.c

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/****************************************************************************
*																			*
*					cryptlib Triple DES Encryption Routines					*
*						Copyright Peter Gutmann 1994-2005					*
*																			*
****************************************************************************/

#include <stdlib.h>
#if defined( INC_ALL )
  #include "crypt.h"
  #include "context.h"
  #include "des.h"
#elif defined( INC_CHILD )
  #include "../crypt.h"
  #include "context.h"
  #include "../crypt/des.h"
#else
  #include "crypt.h"
  #include "context/context.h"
  #include "crypt/des.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 testLoop( const DES_TEST *testData, int iterations )
	{
	const CAPABILITY_INFO *capabilityInfo = get3DESCapability();
	BYTE temp[ DES_BLOCKSIZE ];
	int i;

	for( i = 0; i < iterations; i++ )
		{
		CONTEXT_INFO contextInfo;
		CONV_INFO contextData;
		BYTE keyData[ DES3_KEYSIZE ];
		BYTE desKeyData[ DES_BLOCKSIZE * 3 ];
		int status;

		memcpy( temp, testData[ i ].plaintext, DES_BLOCKSIZE );
		memcpy( desKeyData, testData[ i ].key, DES_BLOCKSIZE );
		memcpy( desKeyData + DES_BLOCKSIZE, testData[ i ].key, DES_BLOCKSIZE );
		memcpy( desKeyData + ( DES_BLOCKSIZE * 2 ), testData[ i ].key, DES_BLOCKSIZE );

		/* The self-test uses weak keys, which means they'll be rejected by 
		   the key-load function if it checks for these.  For the OpenSSL
		   DES implementation we can kludge around this by temporarily 
		   clearing the global des_check_key value, but for other 
		   implementations some alternative workaround will be necessary */
		staticInitContext( &contextInfo, CONTEXT_CONV, capabilityInfo,
						   &contextData, sizeof( CONV_INFO ), keyData );
		des_check_key = FALSE;
		status = capabilityInfo->initKeyFunction( &contextInfo, desKeyData,
												  DES_BLOCKSIZE * 3 );
		des_check_key = TRUE;
		if( cryptStatusOK( status ) )
			status = capabilityInfo->encryptFunction( &contextInfo, temp, 
													  DES_BLOCKSIZE );
		staticDestroyContext( &contextInfo );
		if( cryptStatusError( status ) || \
			memcmp( testData[ i ].ciphertext, temp, DES_BLOCKSIZE ) )
			return( CRYPT_ERROR );
		}

	return( CRYPT_OK );
	}

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

	return( CRYPT_OK );
	}

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

/* Return context subtype-specific information */

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

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

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

/* Encrypt/decrypt data in ECB mode */

static int encryptECB( 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-- > 0 )
		{
		/* 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 );
	}

static int decryptECB( 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-- > 0 )
		{
		/* 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 */

static int encryptCBC( 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 );
	}

static int decryptCBC( 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 */

static int encryptCFB( 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 > 0 )
		{
		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 > 0 )
		{
		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;
		buffer += ivCount;
		}

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

	return( CRYPT_OK );
	}