实验一-密码引擎-加密API实现与测试

• 实现 GM/T 0018-2012 密码设备应用接口规范中部分接口函数。
• 以 SDF_ExternalEncrypt_ECC、 SDF_HashUpdate 等为例。

// sdf.h

int SDF_ExternalEncrypt_ECC(
		void* hSessionHandle,
		unsigned int uiAlgID,
		ECCrefPublicKey* pucPublicKey,
		unsigned char* pucData,
		unsigned int  uiDataLength,
		ECCCipher* pucEncData
	);

int SDF_ExternalDecrypt_ECC(
		void* hSessionHandle,
		unsigned int uiAlgID,
		ECCrefPrivateKey* pucPrivateKey,
		ECCCipher* pucEncData,
		unsigned char* pucData,
		unsigned int* puiDataLength
	);

int SDF_HashInit(void* hSessionHandle,
		unsigned int uiAlgID,
		ECCrefPublicKey* pucPublicKey,
		unsigned char* pucID,
		unsigned int uiIDLength);

int SDF_HashUpdate(void* hSessionHandle,
		unsigned char* pucData,
		unsigned int uiDataLength);

int SDF_HashFinal(void* hSessionHandle,
		unsigned char* pucHash,
		unsigned int* puiHashLength);

调用 OpenSSL 接口来封装上述函数。

// sdf.c

int SDF_ExternalEncrypt_ECC(void* hSessionHandle, unsigned int uiAlgID, ECCrefPublicKey* pucPublicKey, unsigned char* pucData, unsigned int uiDataLength, ECCCipher* pucEncData)
{
	if (uiDataLength > 32) {
		printf("Too much bytes for pucData!\n");
		return SDR_PKOPERR;
	}
	int error_code;
	unsigned char c1[65], c3[32];
	unsigned char* c2;
	int i;
	unsigned char pub_key[65] = { 0x04 };
	for (i = 1; i < 33; i++) {
		pub_key[i] = pucPublicKey->x[i-1];
	}
	for (i = 33; i < 65; i++) {
		pub_key[i] = pucPublicKey->y[i-33];
	}
	
	if (!(c2 = (unsigned char*)malloc(uiDataLength)))
	{
		printf("Memory allocation failed!\n");
		return SDR_NOBUFFER;
	}
	if (error_code = sm2_encrypt(pucData, uiDataLength, pub_key, c1, c3, c2)) {
		printf("Create SM2 ciphertext by using input defined in standard failed!\n");
		free(c2);
		return SDR_PKOPERR;
	}
	for (i = 0; i < 32; i++) {
		pucEncData->x[i] = c1[i+1];
	}
	for (i = 0; i < 32; i++) {
		pucEncData->y[i] = c1[i+33];
	}
	for (i = 0; i < uiDataLength; i++) {
		pucEncData->C[i] = c2[i];
	}
	for (i = uiDataLength; i < 32; i++) {
		pucEncData->C[i] = 0x00;
	}
	for (i = 0; i < 32; i++) {
		pucEncData->M[i] = c3[i];
	}
	return SDR_OK;
}

• 其中函数 sm2_encrypt 是参考了 Github 上的项目，可以从此连接进行查看。 https://github.com/greendow/SM2-encrypt-and-decrypt
• 解密后的结果与原先一致：
  

// sdf.h

int SDF_HashInit(void* hSessionHandle,
		unsigned int uiAlgID,
		ECCrefPublicKey* pucPublicKey,
		unsigned char* pucID,
		unsigned int uiIDLength);

int SDF_HashUpdate(void* hSessionHandle,
		unsigned char* pucData,
		unsigned int uiDataLength);

int SDF_HashFinal(void* hSessionHandle,
		unsigned char* pucHash,
		unsigned int* puiHashLength);

// sdf.c

int SDF_HashInit(void* hSessionHandle, unsigned int uiAlgID,
 ECCrefPublicKey* pucPublicKey, unsigned char* pucID, unsigned int uiIDLength) {
	
	EVP_MD_CTX* md_ctx = EVP_MD_CTX_new();
	const EVP_MD* md = EVP_sm3();
	EVP_DigestInit_ex(md_ctx, md, NULL);
	
	return SDR_OK;
	
}

int SDF_HashUpdate(void* hSessionHandle, unsigned char* pucData, unsigned int uiDataLength) {
	
	EVP_DigestUpdate(md_ctx, pucData, uiDataLength);

	return SDR_OK;

}

int SDF_HashFinal(void* hSessionHandle, unsigned char* pucHash, unsigned int* puiHashLength) {

	EVP_DigestFinal_ex(md_ctx, pucHash, puiHashLength);
	EVP_MD_CTX_free(md_ctx);
	return SDR_OK;
}

• SDF 规范中与哈希运算相关的函数都可以直接调用 OpenSSL 中的接口，稍作修改即可完成。
• 计算字符串“20191210”的散列值，与 OpenSSL 的计算结果一致。