1# Importing a Key in Plaintext (C/C++)
2
3
4This topic walks you through on how to import an ECC key. For details about the scenarios and supported algorithm specifications, see [Supported Algorithms](huks-key-import-overview.md#supported-algorithms).
5
6## Add the dynamic library in the CMake script.
7```txt
8   target_link_libraries(entry PUBLIC libhuks_ndk.z.so)
9```
10
11## How to Develop
12
131. Set the alias **keyAlias** of the key to import.
14   The key alias cannot exceed 128 bytes.
15
162. Encapsulate the key property set and key material. Construct the key property set **paramSet** using [OH_Huks_InitParamSet](../../reference/apis-universal-keystore-kit/_huks_param_set_api.md#oh_huks_initparamset), [OH_Huks_AddParams](../../reference/apis-universal-keystore-kit/_huks_param_set_api.md#oh_huks_addparams), and [OH_Huks_BuildParamSet](../../reference/apis-universal-keystore-kit/_huks_param_set_api.md#oh_huks_buildparamset).
17   - ** paramSet** must contain [OH_Huks_KeyAlg](../../reference/apis-universal-keystore-kit/_huks_type_api.md#oh_huks_keyalg), [OH_Huks_KeySize](../../reference/apis-universal-keystore-kit/_huks_type_api.md#oh_huks_keysize), and [OH_Huks_KeyPurpose](../../reference/apis-universal-keystore-kit/_huks_type_api.md#oh_huks_keypurpose).
18   - The key material must comply with the [HUKS key material format](huks-concepts.md#key-material-format).
19
203. Use [OH_Huks_ImportKeyItem](../../reference/apis-universal-keystore-kit/_huks_key_api.md#oh_huks_importkeyitem) to import the key.
21
22```c++
23/* Import an ECC key in plaintext. */
24#include "huks/native_huks_api.h"
25#include "huks/native_huks_param.h"
26#include <string.h>
27OH_Huks_Result InitParamSet(struct OH_Huks_ParamSet **paramSet, const struct OH_Huks_Param *params,
28                            uint32_t paramCount) {
29    OH_Huks_Result ret = OH_Huks_InitParamSet(paramSet);
30    if (ret.errorCode != OH_HUKS_SUCCESS) {
31        return ret;
32    }
33    ret = OH_Huks_AddParams(*paramSet, params, paramCount);
34    if (ret.errorCode != OH_HUKS_SUCCESS) {
35        OH_Huks_FreeParamSet(paramSet);
36        return ret;
37    }
38    ret = OH_Huks_BuildParamSet(paramSet);
39    if (ret.errorCode != OH_HUKS_SUCCESS) {
40        OH_Huks_FreeParamSet(paramSet);
41        return ret;
42    }
43    return ret;
44}
45struct OH_Huks_Param g_testImportKeyParam[] = {{.tag = OH_HUKS_TAG_ALGORITHM, .uint32Param = OH_HUKS_ALG_ECC},
46                                                 {.tag = OH_HUKS_TAG_PURPOSE, .uint32Param = OH_HUKS_KEY_PURPOSE_AGREE},
47                                                 {.tag = OH_HUKS_TAG_KEY_SIZE, .uint32Param = OH_HUKS_ECC_KEY_SIZE_256},
48                                                 {.tag = OH_HUKS_TAG_DIGEST, .uint32Param = OH_HUKS_DIGEST_NONE}};
49
50static napi_value ImportKey(napi_env env, napi_callback_info info) {
51    const char *alias = "test_import";
52    struct OH_Huks_Blob aliasBlob = {.size = (uint32_t)strlen(alias), .data = (uint8_t *)alias};
53    /* Public key in DER format, which is used to import the key. */
54    uint8_t pubKey[OH_HUKS_ECC_KEY_SIZE_256] = {
55        0x30, 0x2A, 0x30, 0x05, 0x06, 0x03, 0x2B, 0x65, 0x6E, 0x03, 0x21, 0x00, 0xD2, 0x36, 0x9E, 0xCF,
56        0xF0, 0x61, 0x5B, 0x73, 0xCE, 0x4F, 0xF0, 0x40, 0x2B, 0x89, 0x18, 0x3E, 0x06, 0x33, 0x60, 0xC6
57    };
58    struct OH_Huks_Blob publicKey = {OH_HUKS_ECC_KEY_SIZE_256, pubKey};
59    struct OH_Huks_ParamSet *testImportKeyParamSet = nullptr;
60    struct OH_Huks_Result ohResult;
61    do {
62        ohResult = InitParamSet(&testImportKeyParamSet, g_testImportKeyParam,
63                                sizeof(g_testImportKeyParam) / sizeof(OH_Huks_Param));
64        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
65            break;
66        }
67        if (ohResult.errorCode != OH_HUKS_SUCCESS) {
68            break;
69        }
70        /* 4. Import Key */
71        char newKey[] = "test_import";
72        struct OH_Huks_Blob newKeyAlias = {.size = (uint32_t)strlen(newKey), .data = (uint8_t *)newKey};
73        ohResult = OH_Huks_ImportKeyItem(&newKeyAlias, testImportKeyParamSet, &publicKey);
74    } while (0);
75    OH_Huks_FreeParamSet(&testImportKeyParamSet);
76    napi_value ret;
77    napi_create_int32(env, ohResult.errorCode, &ret);
78    return ret;
79}
80```
81