HMAC(C/C++)

HMAC是密钥相关的哈希运算消息认证码（Hash-based Message Authentication Code），是一种基于Hash函数和密钥进行消息认证的方法。

在CMake脚本中链接相关动态库

   target_link_libraries(entry PUBLIC libhuks_ndk.z.so)

开发步骤

生成密钥

1. 指定密钥别名。
2. 初始化密钥属性集。
3. 调用OH_Huks_GenerateKeyItem生成密钥，HMAC支持的规格请参考[密钥生成]。
4. 开发前请熟悉鸿蒙开发指导文档：gitee.com/li-shizhen-skin/harmony-os/blob/master/README.md点击或者复制转到。

除此之外，开发者也可以参考[密钥导入]的规格介绍，导入已有的密钥。

执行HMAC

1. 获取密钥别名。
2. 获取待运算的数据。
3. 调用[OH_Huks_InitParamSet]指定算法参数配置。
4. 调用[OH_Huks_InitSession]初始化密钥会话，并获取会话的句柄handle。
5. 调用[OH_Huks_FinishSession]结束密钥会话，获取哈希后的数据。

#include "huks/native_huks_api.h"
#include "huks/native_huks_param.h"
#include <string.h>
OH_Huks_Result InitParamSet(
    struct OH_Huks_ParamSet **paramSet,
    const struct OH_Huks_Param *params,
    uint32_t paramCount)
{
    OH_Huks_Result ret = OH_Huks_InitParamSet(paramSet);
    if (ret.errorCode != OH_HUKS_SUCCESS) {
        return ret;
    }
    ret = OH_Huks_AddParams(*paramSet, params, paramCount);
    if (ret.errorCode != OH_HUKS_SUCCESS) {
        OH_Huks_FreeParamSet(paramSet);
        return ret;
    }
    ret = OH_Huks_BuildParamSet(paramSet);
    if (ret.errorCode != OH_HUKS_SUCCESS) {
        OH_Huks_FreeParamSet(paramSet);
        return ret;
    }
    return ret;
}

static struct OH_Huks_Param g_genHmacParams[] = {
    {
        .tag = OH_HUKS_TAG_ALGORITHM,
        .uint32Param = OH_HUKS_ALG_HMAC
    }, {
        .tag = OH_HUKS_TAG_PURPOSE,
        .uint32Param = OH_HUKS_KEY_PURPOSE_MAC
    }, {
        .tag = OH_HUKS_TAG_KEY_SIZE,
        .uint32Param = OH_HUKS_AES_KEY_SIZE_256
    }, {
        .tag = OH_HUKS_TAG_DIGEST,
        .uint32Param = OH_HUKS_DIGEST_SHA384
    }
};

static const uint32_t HMAC_COMMON_SIZE = 1024;
OH_Huks_Result HksHmacTest(
        const struct OH_Huks_Blob *keyAlias,
        const struct OH_Huks_ParamSet *hmacParamSet, const struct OH_Huks_Blob *inData, struct OH_Huks_Blob *hashText)
{
    uint8_t handleE[sizeof(uint64_t)] = {0};
    struct OH_Huks_Blob handle = {sizeof(uint64_t), handleE};
    OH_Huks_Result ret = OH_Huks_InitSession(keyAlias, hmacParamSet, &handle, nullptr);
    if (ret.errorCode != OH_HUKS_SUCCESS) {
        return ret;
    }
    ret = OH_Huks_FinishSession(&handle, hmacParamSet, inData, hashText);
    return ret;
}

static napi_value HmacKey(napi_env env, napi_callback_info info)
{
    char tmpKeyAlias[] = "test_hmac";
    struct OH_Huks_Blob keyAlias = { (uint32_t)strlen(tmpKeyAlias), (uint8_t *)tmpKeyAlias };
    struct OH_Huks_ParamSet *hmacParamSet = nullptr;
    OH_Huks_Result ohResult;
    do {
        /* 1. Generate Key */
        /*
        * 模拟生成密钥场景
        * 1.1. 确定密钥别名
        */
        /*
        * 1.2. 获取生成密钥算法参数配置
        */
        ohResult = InitParamSet(&hmacParamSet, g_genHmacParams, sizeof(g_genHmacParams) / sizeof(OH_Huks_Param));
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }
        /*
        * 1.3. 调用generateKeyItem
        */
        ohResult = OH_Huks_GenerateKeyItem(&keyAlias, hmacParamSet, nullptr);
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }
        /* 2. Hmac */
        /*
        * 模拟哈希场景
        * 2.1. 获取密钥别名
        */
        /*
        * 2.2. 获取待哈希的数据
        */
        char tmpInData[] = "HMAC_MAC_INDATA_1";
        struct OH_Huks_Blob inData = { (uint32_t)strlen(tmpInData), (uint8_t *)tmpInData };
        uint8_t cipher[HMAC_COMMON_SIZE] = {0};
        struct OH_Huks_Blob hashText = {HMAC_COMMON_SIZE, cipher};
        /*
        * 2.3. 调用initSession获取handle
        */
        /*
        * 2.4. 调用finishSession获取哈希后的内容
        */
        ohResult = HksHmacTest(&keyAlias, hmacParamSet, &inData, &hashText);
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }
    } while (0);
    OH_Huks_FreeParamSet(&hmacParamSet);
}