📄 aesenc.c

📁 C语言环境下的AES加密算法
💻 C
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	//	core part
	AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
	for( i=0; i<BufLen; i++)
		CipherTxt[i] = (BYTE) (AlgInfo->Buffer[i] ^ AlgInfo->ChainVar[i]);

	//
	*CipherTxtLen = BufLen;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
static RET_VAL CFB_EncFinal(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*CipherTxt, 	//	鞠龋巩捞 免仿瞪 pointer
		DWORD		*CipherTxtLen)	//	免仿登绰 鞠龋巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BufLen=AlgInfo->BufLen;

	//	Check Output Memory Size
	*CipherTxtLen = BufLen;

	//	core part
	AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
	BlockXor(AlgInfo->ChainVar, AlgInfo->ChainVar, AlgInfo->Buffer);
	memcpy(CipherTxt, AlgInfo->ChainVar, BufLen);

	//
	*CipherTxtLen = BufLen;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
RET_VAL	AES_EncFinal(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*CipherTxt, 	//	鞠龋巩捞 免仿瞪 pointer
		DWORD		*CipherTxtLen)	//	免仿登绰 鞠龋巩狼 官捞飘 荐
{
	switch( AlgInfo->ModeID ) {
		case AI_ECB :	return ECB_EncFinal(AlgInfo, CipherTxt, CipherTxtLen);
		case AI_CBC :	return CBC_EncFinal(AlgInfo, CipherTxt, CipherTxtLen);
		case AI_OFB :	return OFB_EncFinal(AlgInfo, CipherTxt, CipherTxtLen);
		case AI_CFB :	return CFB_EncFinal(AlgInfo, CipherTxt, CipherTxtLen);
		default :		return CTR_FATAL_ERROR;
	}
}

/**************************************************************************
*
*/
RET_VAL	AES_DecInit(
		AES_ALG_INFO	*AlgInfo)
{
	AlgInfo->BufLen = 0;
	if( AlgInfo->ModeID!=AI_ECB )
		memcpy(AlgInfo->ChainVar, AlgInfo->IV, AES_BLOCK_LEN);
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
static RET_VAL ECB_DecUpdate(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*CipherTxt, 	//	涝仿登绰 鞠龋巩狼 pointer
		DWORD		CipherTxtLen,	//	涝仿登绰 鞠龋巩狼 官捞飘 荐
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BlockLen=AES_BLOCK_LEN;
	DWORD		BufLen=AlgInfo->BufLen;

	//
	*PlainTxtLen = BufLen + CipherTxtLen;

	//	No one block
	if( BufLen+CipherTxtLen <= BlockLen ) {
		memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)CipherTxtLen);
		AlgInfo->BufLen += CipherTxtLen;
		*PlainTxtLen = 0;
		return CTR_SUCCESS;
	}

	//	control the case that CipherTxt and PlainTxt are the same buffer
	if( CipherTxt==PlainTxt )	return CTR_FATAL_ERROR;

	//	first block
	*PlainTxtLen = BufLen + CipherTxtLen;
	memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)(BlockLen - BufLen));
	CipherTxt += BlockLen - BufLen;
	CipherTxtLen -= BlockLen - BufLen;

	//	core part
	BlockCopy(PlainTxt, AlgInfo->Buffer);
	AES_Decrypt(ScheduledKey, PlainTxt);
	PlainTxt += BlockLen;
	while( CipherTxtLen>BlockLen ) {
		BlockCopy(PlainTxt, CipherTxt);
		AES_Decrypt(ScheduledKey, PlainTxt);
		CipherTxt += BlockLen;
		PlainTxt += BlockLen;
		CipherTxtLen -= BlockLen;
	}

	//	save remained data
	memcpy(AlgInfo->Buffer, CipherTxt, (int)CipherTxtLen);
	AlgInfo->BufLen = (AlgInfo->BufLen&0xF0000000) + CipherTxtLen;
	*PlainTxtLen -= CipherTxtLen;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
static RET_VAL CBC_DecUpdate(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*CipherTxt, 	//	涝仿登绰 鞠龋巩狼 pointer
		DWORD		CipherTxtLen,	//	涝仿登绰 鞠龋巩狼 官捞飘 荐
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BlockLen=AES_BLOCK_LEN, BufLen=AlgInfo->BufLen;

	//	Check Output Memory Size
	*PlainTxtLen = BufLen + CipherTxtLen;

	//	No one block
	if( BufLen+CipherTxtLen <= BlockLen ) {
		memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)CipherTxtLen);
		AlgInfo->BufLen += CipherTxtLen;
		*PlainTxtLen = 0;
		return CTR_SUCCESS;
	}

	//	control the case that CipherTxt and PlainTxt are the same buffer
	if( CipherTxt==PlainTxt )	return CTR_FATAL_ERROR;

	//	first block
	*PlainTxtLen = BufLen + CipherTxtLen;
	memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)(BlockLen - BufLen));
	CipherTxt += BlockLen - BufLen;
	CipherTxtLen -= BlockLen - BufLen;

	//	core part
	BlockCopy(PlainTxt, AlgInfo->Buffer);
	AES_Decrypt(ScheduledKey, PlainTxt);
	BlockXor(PlainTxt, PlainTxt, AlgInfo->ChainVar);
	PlainTxt += BlockLen;
	if( CipherTxtLen<=BlockLen ) {
		BlockCopy(AlgInfo->ChainVar, AlgInfo->Buffer);
	}
	else {
		if( CipherTxtLen>BlockLen ) {
			BlockCopy(PlainTxt, CipherTxt);
			AES_Decrypt(ScheduledKey, PlainTxt);
			BlockXor(PlainTxt, PlainTxt, AlgInfo->Buffer);
			CipherTxt += BlockLen;
			PlainTxt += BlockLen;
			CipherTxtLen -= BlockLen;
		}
		while( CipherTxtLen>BlockLen ) {
			BlockCopy(PlainTxt, CipherTxt);
			AES_Decrypt(ScheduledKey, PlainTxt);
			BlockXor(PlainTxt, PlainTxt, CipherTxt-BlockLen);
			CipherTxt += BlockLen;
			PlainTxt += BlockLen;
			CipherTxtLen -= BlockLen;
		}
		BlockCopy(AlgInfo->ChainVar, CipherTxt-BlockLen);
	}

	//	save remained data
	memcpy(AlgInfo->Buffer, CipherTxt, (int)CipherTxtLen);
	AlgInfo->BufLen = (AlgInfo->BufLen&0xF0000000) + CipherTxtLen;
	*PlainTxtLen -= CipherTxtLen;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
static RET_VAL OFB_DecUpdate(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*CipherTxt, 	//	涝仿登绰 鞠龋巩狼 pointer
		DWORD		CipherTxtLen,	//	涝仿登绰 鞠龋巩狼 官捞飘 荐
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BlockLen=AES_BLOCK_LEN;
	DWORD		BufLen=AlgInfo->BufLen;

	//	Check Output Memory Size
	*PlainTxtLen = BufLen + CipherTxtLen;

	//	No one block
	if( BufLen+CipherTxtLen <= BlockLen ) {
		memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)CipherTxtLen);
		AlgInfo->BufLen += CipherTxtLen;
		*PlainTxtLen = 0;
		return CTR_SUCCESS;
	}

	//	control the case that CipherTxt and PlainTxt are the same buffer
	if( PlainTxt==CipherTxt )
		return CTR_FATAL_ERROR;

	//	first block
	*PlainTxtLen = BufLen + CipherTxtLen;
	memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)(BlockLen - BufLen));
	CipherTxt += BlockLen - BufLen;
	CipherTxtLen -= BlockLen - BufLen;

	//	core part
	AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
	BlockXor(PlainTxt, AlgInfo->ChainVar, AlgInfo->Buffer);
	PlainTxt += BlockLen;
	while( CipherTxtLen>BlockLen ) {
		AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
		BlockXor(PlainTxt, AlgInfo->ChainVar, CipherTxt);
		CipherTxt += BlockLen;
		PlainTxt += BlockLen;
		CipherTxtLen -= BlockLen;
	}

	//	save remained data
	memcpy(AlgInfo->Buffer, CipherTxt, (int)CipherTxtLen);
	AlgInfo->BufLen = (AlgInfo->BufLen&0xF0000000) + CipherTxtLen;
	*PlainTxtLen -= CipherTxtLen;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
static RET_VAL CFB_DecUpdate(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*CipherTxt, 	//	涝仿登绰 鞠龋巩狼 pointer
		DWORD		CipherTxtLen,	//	涝仿登绰 鞠龋巩狼 官捞飘 荐
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BlockLen=AES_BLOCK_LEN;
	DWORD		BufLen=AlgInfo->BufLen;

	//	Check Output Memory Size
	*PlainTxtLen = BufLen + CipherTxtLen;

	//	No one block
	if( BufLen+CipherTxtLen <= BlockLen ) {
		memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)CipherTxtLen);
		AlgInfo->BufLen += CipherTxtLen;
		*PlainTxtLen = 0;
		return CTR_SUCCESS;
	}

	//	control the case that CipherTxt and PlainTxt are the same buffer
	if( PlainTxt==CipherTxt )
		return CTR_FATAL_ERROR;

	//	first block
	*PlainTxtLen = BufLen + CipherTxtLen;
	memcpy(AlgInfo->Buffer+BufLen, CipherTxt, (int)(BlockLen - BufLen));
	CipherTxt += BlockLen - BufLen;
	CipherTxtLen -= BlockLen - BufLen;

	//	core part
	AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
	BlockXor(PlainTxt, AlgInfo->ChainVar, AlgInfo->Buffer);
	BlockCopy(AlgInfo->ChainVar, AlgInfo->Buffer);
	PlainTxt += BlockLen;
	while( CipherTxtLen>BlockLen ) {
		AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
		BlockXor(PlainTxt, AlgInfo->ChainVar, CipherTxt);
		BlockCopy(AlgInfo->ChainVar, CipherTxt);
		CipherTxt += BlockLen;
		PlainTxt += BlockLen;
		CipherTxtLen -= BlockLen;
	}

	//	save remained data
	memcpy(AlgInfo->Buffer, CipherTxt, (int)CipherTxtLen);
	AlgInfo->BufLen = (AlgInfo->BufLen&0xF0000000) + CipherTxtLen;
	*PlainTxtLen -= CipherTxtLen;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
RET_VAL	AES_DecUpdate(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*CipherTxt, 	//	鞠龋巩捞 免仿瞪 pointer
		DWORD		CipherTxtLen,	//	免仿登绰 鞠龋巩狼 官捞飘 荐
		BYTE		*PlainTxt,		//	涝仿登绰 乞巩狼 pointer
		DWORD		*PlainTxtLen)	//	涝仿登绰 乞巩狼 官捞飘 荐
{
	switch( AlgInfo->ModeID ) {
		case AI_ECB :	return ECB_DecUpdate(AlgInfo, CipherTxt, CipherTxtLen,
											 PlainTxt, PlainTxtLen);
		case AI_CBC :	return CBC_DecUpdate(AlgInfo, CipherTxt, CipherTxtLen,
											 PlainTxt, PlainTxtLen);
		case AI_OFB :	return OFB_DecUpdate(AlgInfo, CipherTxt, CipherTxtLen,
											 PlainTxt, PlainTxtLen);
		case AI_CFB :	return CFB_DecUpdate(AlgInfo, CipherTxt, CipherTxtLen,
											 PlainTxt, PlainTxtLen);
		default :		return CTR_FATAL_ERROR;
	}
}

/**************************************************************************
*
*/
RET_VAL ECB_DecFinal(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BlockLen=AES_BLOCK_LEN, BufLen=AlgInfo->BufLen;
	RET_VAL		ret;

	//	Check Output Memory Size
	if( BufLen==0 ) {
		*PlainTxtLen = 0;
		return CTR_SUCCESS;
	}
	*PlainTxtLen = BlockLen;

	if( BufLen!=BlockLen )	return CTR_CIPHER_LEN_ERROR;

	//	core part
	BlockCopy(PlainTxt, AlgInfo->Buffer);
	AES_Decrypt(ScheduledKey, PlainTxt);

	//	Padding Check
	ret = PaddCheck(PlainTxt, BlockLen, AlgInfo->PadType);
	if( ret==(DWORD)-3 )	return CTR_PAD_CHECK_ERROR;
	if( ret==(DWORD)-1 )	return CTR_FATAL_ERROR;

	*PlainTxtLen = BlockLen - ret;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
RET_VAL CBC_DecFinal(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BlockLen=AES_BLOCK_LEN, BufLen=AlgInfo->BufLen;
	RET_VAL		ret;

	//	Check Output Memory Size
	if( BufLen==0 ) {
		*PlainTxtLen = 0;
		return CTR_SUCCESS;
	}
	*PlainTxtLen = BlockLen;

	if( BufLen!=BlockLen )	return CTR_CIPHER_LEN_ERROR;

	//	core part
	BlockCopy(PlainTxt, AlgInfo->Buffer);
	AES_Decrypt(ScheduledKey, PlainTxt);
	BlockXor(PlainTxt, PlainTxt, AlgInfo->ChainVar);
	BlockCopy(AlgInfo->ChainVar, AlgInfo->Buffer);

	//	Padding Check
	ret = PaddCheck(PlainTxt, BlockLen, AlgInfo->PadType);
	if( ret==(DWORD)-3 )	return CTR_PAD_CHECK_ERROR;
	if( ret==(DWORD)-1 )	return CTR_FATAL_ERROR;

	*PlainTxtLen = BlockLen - ret;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
RET_VAL OFB_DecFinal(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		i, BufLen=AlgInfo->BufLen;

	//	Check Output Memory Size
	*PlainTxtLen = BufLen;

	//	core part
	AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
	for( i=0; i<BufLen; i++)
		PlainTxt[i] = (BYTE) (AlgInfo->Buffer[i] ^ AlgInfo->ChainVar[i]);

	*PlainTxtLen = BufLen;

	//
	return CTR_SUCCESS;
}


/**************************************************************************
*
*/
RET_VAL CFB_DecFinal(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*PlainTxt,		//	乞巩捞 免仿瞪 pointer
		DWORD		*PlainTxtLen)	//	免仿登绰 乞巩狼 官捞飘 荐
{
	DWORD		*ScheduledKey=AlgInfo->RoundKey;
	DWORD		BufLen=AlgInfo->BufLen;

	//	Check Output Memory Size
	*PlainTxtLen = BufLen;

	//	core part
	AES_Encrypt(ScheduledKey, AlgInfo->ChainVar);
	BlockXor(AlgInfo->ChainVar, AlgInfo->ChainVar, AlgInfo->Buffer);
	memcpy(PlainTxt, AlgInfo->ChainVar, BufLen);

	*PlainTxtLen = BufLen;

	//
	return CTR_SUCCESS;
}

/**************************************************************************
*
*/
RET_VAL	AES_DecFinal(
		AES_ALG_INFO	*AlgInfo,
		BYTE		*PlainTxt,		//	涝仿登绰 乞巩狼 pointer
		DWORD		*PlainTxtLen)	//	涝仿登绰 乞巩狼 官捞飘 荐
{
	switch( AlgInfo->ModeID ) {
		case AI_ECB :	return ECB_DecFinal(AlgInfo, PlainTxt, PlainTxtLen);
		case AI_CBC :	return CBC_DecFinal(AlgInfo, PlainTxt, PlainTxtLen);
		case AI_OFB :	return OFB_DecFinal(AlgInfo, PlainTxt, PlainTxtLen);
		case AI_CFB :	return CFB_DecFinal(AlgInfo, PlainTxt, PlainTxtLen);
		default :		return CTR_FATAL_ERROR;
	}
}

/*************** END OF FILE **********************************************/
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