• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# 获取密钥属性(C/C++)
2
3<!--Kit: Universal Keystore Kit-->
4<!--Subsystem: Security-->
5<!--Owner: @wutiantian-gitee-->
6<!--Designer: @HighLowWorld-->
7<!--Tester: @wxy1234564846-->
8<!--Adviser: @zengyawen-->
9
10HUKS提供了接口供业务获取指定密钥的相关属性。在获取指定密钥属性前，需要确保已在HUKS中生成或导入持久化存储的密钥。
11>**说明：**
12> 轻量级设备不支持获取密钥属性功能。
13
14## 在CMake脚本中链接相关动态库
15```txt
16target_link_libraries(entry PUBLIC libhuks_ndk.z.so)
17```
18## 开发步骤
19
201. 构造对应参数。
21   - keyAlias：密钥别名，封装成[OH_Huks_Blob](../../reference/apis-universal-keystore-kit/capi-hukstypeapi-oh-huks-blob.md)结构，密钥别名最大长度为128字节。
22   - paramSetIn：预留参数，暂不需要处理，传空即可。
23   - paramSetOut：用于放置获取到的参数集结果，为[OH_Huks_ParamSet](../../reference/apis-universal-keystore-kit/capi-hukstypeapi-oh-huks-paramset.md)类型对象，需要业务提前申请好内存，需申请足够容纳获取到的密钥属性集的内存大小。
24
252. 调用接口[OH_Huks_GetKeyItemParamSet](../../reference/apis-universal-keystore-kit/capi-native-huks-api-h.md#oh_huks_getkeyitemparamset)，传入上述参数。
26
273. 返回值为成功码/错误码，获取成功后，从参数集中读取需要的参数。
28
29```c++
30#include "huks/native_huks_api.h"
31#include "huks/native_huks_param.h"
32#include "napi/native_api.h"
33#include <cstring>
34
35OH_Huks_Result InitParamSet(struct OH_Huks_ParamSet **paramSet, const struct OH_Huks_Param *params,
36                            uint32_t paramCount)
37{
38    OH_Huks_Result ret = OH_Huks_InitParamSet(paramSet);
39    if (ret.errorCode != OH_HUKS_SUCCESS) {
40        return ret;
41    }
42    ret = OH_Huks_AddParams(*paramSet, params, paramCount);
43    if (ret.errorCode != OH_HUKS_SUCCESS) {
44        OH_Huks_FreeParamSet(paramSet);
45        return ret;
46    }
47    ret = OH_Huks_BuildParamSet(paramSet);
48    if (ret.errorCode != OH_HUKS_SUCCESS) {
49        OH_Huks_FreeParamSet(paramSet);
50        return ret;
51    }
52    return ret;
53}
54
55struct OH_Huks_Param g_testGenerateKeyParam[] = {{.tag = OH_HUKS_TAG_ALGORITHM, .uint32Param = OH_HUKS_ALG_ECC},
56                                                 {.tag = OH_HUKS_TAG_PURPOSE, .uint32Param = OH_HUKS_KEY_PURPOSE_AGREE},
57                                                 {.tag = OH_HUKS_TAG_KEY_SIZE, .uint32Param = OH_HUKS_ECC_KEY_SIZE_256},
58                                                 {.tag = OH_HUKS_TAG_DIGEST, .uint32Param = OH_HUKS_DIGEST_NONE}};
59
60static OH_Huks_Result GenerateKeyHelper(const char *alias)
61{
62    struct OH_Huks_Blob aliasBlob = {.size = (uint32_t)strlen(alias), .data = (uint8_t *)alias};
63    struct OH_Huks_ParamSet *testGenerateKeyParamSet = nullptr;
64    struct OH_Huks_Result ohResult;
65    do {
66        /* 1.初始化密钥属性集 */
67        ohResult = InitParamSet(&testGenerateKeyParamSet, g_testGenerateKeyParam,
68                                sizeof(g_testGenerateKeyParam) / sizeof(OH_Huks_Param));
69        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
70            break;
71        }
72        /* 1.生成密钥 */
73        ohResult = OH_Huks_GenerateKeyItem(&aliasBlob, testGenerateKeyParamSet, nullptr);
74    } while (0);
75    OH_Huks_FreeParamSet(&testGenerateKeyParamSet);
76    return ohResult;
77}
78
79static napi_value GetKeyParamSet(napi_env env, napi_callback_info info)
80{
81    /* 1. 参数构造：确定密钥别名 */
82    const char *alias = "test_key";
83    struct OH_Huks_Blob aliasBlob = { .size = (uint32_t)strlen(alias), .data = (uint8_t *)alias };
84
85    /* 生成密钥 */
86    OH_Huks_Result genResult = GenerateKeyHelper(alias);
87    if (genResult.errorCode != OH_HUKS_SUCCESS) {
88        napi_value ret;
89        napi_create_int32(env, genResult.errorCode, &ret);
90        return ret;
91    }
92
93    const size_t paramSetSize = 512;
94    /* 构造参数：为参数集申请内存
95     * 请业务按实际情况评估大小进行申请
96     */
97    struct OH_Huks_ParamSet *outParamSet = static_cast<struct OH_Huks_ParamSet *>(malloc(paramSetSize));
98    if (outParamSet == nullptr) {
99        return nullptr;
100    }
101    outParamSet->paramSetSize = paramSetSize;
102    struct OH_Huks_Result ohResult;
103    do {
104        /* 2. 获取密钥属性集 */
105        ohResult = OH_Huks_GetKeyItemParamSet(&aliasBlob, nullptr, outParamSet);
106        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
107            break;
108        }
109        /* 3. 从参数集中读取参数，以OH_HUKS_TAG_PURPOSE为例 */
110        OH_Huks_Param *purposeParam = nullptr; // 无需申请内存，获取后指针指向该参数在参数集中所处内存地址
111        ohResult = OH_Huks_GetParam(outParamSet, OH_HUKS_TAG_PURPOSE, &purposeParam);
112        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
113            break;
114        }
115    } while (0);
116    OH_Huks_FreeParamSet(&outParamSet);
117    napi_value ret;
118    napi_create_int32(env, ohResult.errorCode, &ret);
119    return ret;
120}
121```
122