密鑰派生(C/C++)

以HKDF256密鑰為例，完成密鑰派生。具體的場景介紹及支持的算法規格，請參考[密鑰生成支持的算法]。

在CMake腳本中鏈接相關動態庫

target_link_libraries(entry PUBLIC libhuks_ndk.z.so)

開發步驟

生成密鑰

指定密鑰別名。
初始化密鑰屬性集，可指定參數，OH_HUKS_TAG_DERIVED_AGREED_KEY_STORAGE_FLAG（可選），用于標識基于該密鑰派生出的密鑰是否由HUKS管理。
- 當TAG設置為OH_HUKS_STORAGE_ONLY_USED_IN_HUKS時，表示基于該密鑰派生出的密鑰，由HUKS管理，可保證派生密鑰全生命周期不出安全環境。
- 當TAG設置為OH_HUKS_STORAGE_KEY_EXPORT_ALLOWED時，表示基于該密鑰派生出的密鑰，返回給調用方管理，由業務自行保證密鑰安全。
- 若業務未設置TAG的具體值，表示基于該密鑰派生出的密鑰，即可由HUKS管理，也可返回給調用方管理，業務可在后續派生時再選擇使用何種方式保護密鑰。
調用OH_Huks_GenerateKeyItem生成密鑰，具體請參考[密鑰生成]。
開發前請熟悉鴻蒙開發指導文檔 ：[gitee.com/li-shizhen-skin/harmony-os/blob/master/README.md]

除此之外，開發者也可以參考[密鑰導入]，導入已有的密鑰。

密鑰派生

獲取密鑰別名、指定對應的屬性參數HuksOptions。
可指定參數OH_HUKS_TAG_DERIVED_AGREED_KEY_STORAGE_FLAG（可選），用于標識派生得到的密鑰是否由HUKS管理。

生成	派生	規格
OH_HUKS_STORAGE_ONLY_USED_IN_HUKS	OH_HUKS_STORAGE_ONLY_USED_IN_HUKS	密鑰由HUKS管理
OH_HUKS_STORAGE_KEY_EXPORT_ALLOWED	OH_HUKS_STORAGE_KEY_EXPORT_ALLOWED	密鑰返回給調用方管理
未指定TAG具體值	OH_HUKS_STORAGE_ONLY_USED_IN_HUKS	密鑰由HUKS管理
未指定TAG具體值	OH_HUKS_STORAGE_KEY_EXPORT_ALLOWED	密鑰返回給調用方管理
未指定TAG具體值	未指定TAG具體值	密鑰返回給調用方管理

注：派生時指定的TAG值，不可與生成時指定的TAG值沖突。表格中僅列舉有效的指定方式。

調用[OH_Huks_InitSession]初始化密鑰會話，并獲取會話的句柄handle。
調用[OH_Huks_UpdateSession]更新密鑰會話。
調用[OH_Huks_FinishSession]結束密鑰會話，完成派生。

鴻蒙文檔.png

刪除密鑰

當密鑰廢棄不用時，需要調用OH_Huks_DeleteKeyItem刪除密鑰。

#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 const uint32_t DERIVE_KEY_SIZE_32 = 32;
static struct OH_Huks_Blob g_deriveKeyAlias = {
    (uint32_t)strlen("test_derive"),
    (uint8_t *)"test_derive"
};
static struct OH_Huks_Param g_genDeriveParams[] = {
    {
        .tag =  OH_HUKS_TAG_ALGORITHM,
        .uint32Param = OH_HUKS_ALG_AES
    }, {
        .tag =  OH_HUKS_TAG_PURPOSE,
        .uint32Param = OH_HUKS_KEY_PURPOSE_DERIVE
    }, {
        .tag =  OH_HUKS_TAG_DIGEST,
        .uint32Param = OH_HUKS_DIGEST_SHA256
    }, {
        .tag =  OH_HUKS_TAG_KEY_SIZE,
        .uint32Param = OH_HUKS_AES_KEY_SIZE_256
    }
};
static struct OH_Huks_Param g_hkdfParams[] = {
    {
        .tag =  OH_HUKS_TAG_ALGORITHM,
        .uint32Param = OH_HUKS_ALG_HKDF
    }, {
        .tag =  OH_HUKS_TAG_PURPOSE,
        .uint32Param = OH_HUKS_KEY_PURPOSE_DERIVE
    }, {
        .tag =  OH_HUKS_TAG_DIGEST,
        .uint32Param = OH_HUKS_DIGEST_SHA256
    }, {
        .tag =  OH_HUKS_TAG_DERIVE_KEY_SIZE,
        .uint32Param = DERIVE_KEY_SIZE_32
    }
};
static struct OH_Huks_Param g_hkdfFinishParams[] = {
    {
        .tag =  OH_HUKS_TAG_DERIVED_AGREED_KEY_STORAGE_FLAG,
        .uint32Param = OH_HUKS_STORAGE_ONLY_USED_IN_HUKS
    }, {
        .tag =  OH_HUKS_TAG_KEY_ALIAS,
        .blob = g_deriveKeyAlias
    }, {
        .tag =  OH_HUKS_TAG_ALGORITHM,
        .uint32Param = OH_HUKS_ALG_HKDF
    }, {
        .tag =  OH_HUKS_TAG_KEY_SIZE,
        .uint32Param = DERIVE_KEY_SIZE_32
    }, {
        .tag =  OH_HUKS_TAG_PURPOSE,
        .uint32Param = OH_HUKS_KEY_PURPOSE_DERIVE
    }, {
        .tag =  OH_HUKS_TAG_DIGEST,
        .uint32Param = OH_HUKS_DIGEST_SHA256
    }
};
static const uint32_t COMMON_SIZE = 2048;
static const char *g_deriveInData = "Hks_HKDF_Derive_Test_00000000000000000000000000000000000000000000000000000000000"
                                    "00000000000000000000000000000000000000000000000000000000000000000000000000000000"
                                    "0000000000000000000000000000000000000000000000000000000000000000000000000_string";
static napi_value DeriveKey(napi_env env, napi_callback_info info)
{
    struct OH_Huks_Blob genAlias = {
        (uint32_t)strlen("test_signVerify"),
        (uint8_t *)"test_signVerify"
    };
    struct OH_Huks_Blob inData = {
        (uint32_t)strlen(g_deriveInData),
        (uint8_t *)g_deriveInData
    };
    struct OH_Huks_ParamSet *genParamSet = nullptr;
    struct OH_Huks_ParamSet *hkdfParamSet = nullptr;
    struct OH_Huks_ParamSet *hkdfFinishParamSet = nullptr;
    OH_Huks_Result ohResult;
    do {
        ohResult = InitParamSet(&genParamSet, g_genDeriveParams, sizeof(g_genDeriveParams) / sizeof(OH_Huks_Param));
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }

        ohResult = InitParamSet(&hkdfParamSet, g_hkdfParams, sizeof(g_hkdfParams) / sizeof(OH_Huks_Param));
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
           break;
        }

        // finish paramset
        ohResult = InitParamSet(&hkdfFinishParamSet, g_hkdfFinishParams, sizeof(g_hkdfFinishParams) / sizeof(OH_Huks_Param));
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }

        /* 1. Generate Key */
        ohResult = OH_Huks_GenerateKeyItem(&genAlias, genParamSet, nullptr);
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }
        /* 2. Derive */
        // Init
        uint8_t handleD[sizeof(uint64_t)] = {0};
        struct OH_Huks_Blob handleDerive = { sizeof(uint64_t), handleD };
        ohResult = OH_Huks_InitSession(&genAlias, hkdfParamSet, &handleDerive, nullptr);
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }
        // Update
        uint8_t tmpOut[COMMON_SIZE] = {0};
        struct OH_Huks_Blob outData = { COMMON_SIZE, tmpOut };
        ohResult = OH_Huks_UpdateSession(&handleDerive, hkdfParamSet, &inData, &outData);
        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
            break;
        }
        // Finish
        uint8_t outDataD[COMMON_SIZE] = {0};
        struct OH_Huks_Blob outDataDerive = { COMMON_SIZE, outDataD };
        ohResult = OH_Huks_FinishSession(&handleDerive, hkdfFinishParamSet, &inData, &outDataDerive);
    } while (0);
    (void)OH_Huks_DeleteKeyItem(&genAlias, nullptr);
    (void)OH_Huks_DeleteKeyItem(&g_deriveKeyAlias, nullptr);
    OH_Huks_FreeParamSet(&genParamSet);
    OH_Huks_FreeParamSet(&hkdfParamSet);
    OH_Huks_FreeParamSet(&hkdfFinishParamSet);

    napi_value ret;
    napi_create_int32(env, ohResult.errorCode, &ret);
    return ret;
}