Updated on 2026-06-09 GMT+08:00

Deriving a Shared Key

Function

This API is used to derive a shared key.

Constraints

  • This API is supported only for keys whose key_usage is KEY_AGREEMENT.

Calling Method

For details, see Calling APIs.

Authorization Information

Each account has all the permissions required to call all APIs, but IAM users must be assigned the required permissions.

  • If you are using role/policy-based authorization, see Permissions Policies and Supported Actions for details on the required permissions.
  • If you are using identity policy-based authorization, no identity policy-based permission required for calling this API.

URI

POST /v1.0/{project_id}/kms/derive-shared-secret

Table 1 Path Parameters

Parameter

Mandatory

Type

Description

project_id

Yes

String

Definition

Project ID. For details, see Obtaining a Project ID.

Constraints

N/A

Range

The value returned by the IAM API is used, which contains 32 characters.

Default Value

N/A

Request Parameters

Table 2 Request header parameters

Parameter

Mandatory

Type

Description

X-Auth-Token

Yes

String

Definition

User token. It can be obtained by calling the IAM API. The value of X-Subject-Token in the response header is the user token.

Constraints

N/A

Range

Obtain the value by calling the IAM API for obtaining the user token.

Default Value

N/A

Table 3 Request body parameters

Parameter

Mandatory

Type

Description

key_id

Yes

String

Definition

Key ID

Constraints

  • The value must be a 36-byte ID.

  • The value must match the regular expression ^[0-9a-z]{8}-[0-9a-z]{4}-[0-9a-z]{4}-[0-9a-z]{4}-[0-9a-z]{12}$.

Range

N/A

Default Value

N/A

key_agreement_algorithm

Yes

String

Definition

Key agreement protocol. Only ECDH is supported.

Constraints

N/A

Range

  • ECDH

Default Value

N/A

public_key

Yes

String

Definition

Public key of the peer key pair. Ensure that the public key is from an EC_P256, EC_384, SECP256K1, or SM2 (supported only in Chinese mainland) key pair.

Constraints

  • The public key must be a Base64-encoded string in DER-encoded X.509 format.

Range

N/A

Default Value

N/A

recipient

No

Recipient object

Definition

QingTian encryption computing

Constraints

N/A

Range

N/A

Default Value

N/A

Table 4 Recipient

Parameter

Mandatory

Type

Description

attestation_document

No

String

Definition

QingTian confidential computing attestation document

Constraints

N/A

Range

N/A

Default Value

N/A

key_encryption_algorithm

No

String

Definition

Encryption algorithm. Only RSAES_OAEP_SHA_256 is supported.

Constraints

N/A

Range

  • RSAES_OAEP_SHA_256

Default Value

N/A

Response Parameters

Status code: 200

Table 5 Response body parameters

Parameter

Type

Description

key_id

String

Definition

Key ID

Range

N/A

key_agreement_algorithm

String

Definition

Key agreement algorithm

Range

N/A

shared_secret

String

Definition

Key negotiated between the KMS private key and your peer public key. The value is in Base64 format. If the response body contains ciphertext_recipient, it does not contain shared_secret.

Range

N/A

ciphertext_recipient

String

Definition

Ciphertext of the key negotiated between the KMS private key and your peer public key, which is encrypted using the QingTian attestation document. The ciphertext can be decrypted only by the private key in the confidential environment. Only after the QingTian attestation document is specified can ciphertext_recipient be returned. Otherwise, the plaintext shared key is returned via shared_secret.

Range

N/A

Example Requests

https://kms.cn-north-4.myhuaweicloud.com/v1.0/d4e559b49b3b403da5279723299ed4a6/kms/derive-shared-secret

{
  "key_id" : "f1b8b45f-9f87-43e2-b00c-8a4ca6eb1e39",
  "key_agreement_algorithm" : "ECDH",
  "public_key" : "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE4UPptf7NVo2H+8Mz1V1dMz9x+DGdQSFxwLsqkUSXy4XNgs6bnxMtUB3WuI9GGzIYw21R/+w4lJvNDxYjd/Q1sQ=="
}

Example Responses

Status code: 200

Request succeeded.

{
  "key_id" : "f1b8b45f-9f87-43e2-b00c-8a4ca6eb1e39",
  "key_agreement_algorithm" : "ECDH",
  "shared_secret" : "9ZV21q1r/zKBEibefcb0BgssKTwK0wTTstze45vZ358="
}

SDK Sample Code

The SDK sample code is as follows.

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package com.huaweicloud.sdk.test;

import com.huaweicloud.sdk.core.auth.ICredential;
import com.huaweicloud.sdk.core.auth.BasicCredentials;
import com.huaweicloud.sdk.core.exception.ConnectionException;
import com.huaweicloud.sdk.core.exception.RequestTimeoutException;
import com.huaweicloud.sdk.core.exception.ServiceResponseException;
import com.huaweicloud.sdk.kms.v2.region.KmsRegion;
import com.huaweicloud.sdk.kms.v2.*;
import com.huaweicloud.sdk.kms.v2.model.*;


public class DeriveSharedSecretSolution {

    public static void main(String[] args) {
        // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
        // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
        String ak = System.getenv("CLOUD_SDK_AK");
        String sk = System.getenv("CLOUD_SDK_SK");
        String projectId = "{project_id}";

        ICredential auth = new BasicCredentials()
                .withProjectId(projectId)
                .withAk(ak)
                .withSk(sk);

        KmsClient client = KmsClient.newBuilder()
                .withCredential(auth)
                .withRegion(KmsRegion.valueOf("<YOUR REGION>"))
                .build();
        DeriveSharedSecretRequest request = new DeriveSharedSecretRequest();
        DeriveSharedSecretRequestBody body = new DeriveSharedSecretRequestBody();
        body.withPublicKey("MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE4UPptf7NVo2H+8Mz1V1dMz9x+DGdQSFxwLsqkUSXy4XNgs6bnxMtUB3WuI9GGzIYw21R/+w4lJvNDxYjd/Q1sQ==");
        body.withKeyAgreementAlgorithm(DeriveSharedSecretRequestBody.KeyAgreementAlgorithmEnum.fromValue("ECDH"));
        body.withKeyId("f1b8b45f-9f87-43e2-b00c-8a4ca6eb1e39");
        request.withBody(body);
        try {
            DeriveSharedSecretResponse response = client.deriveSharedSecret(request);
            System.out.println(response.toString());
        } catch (ConnectionException e) {
            e.printStackTrace();
        } catch (RequestTimeoutException e) {
            e.printStackTrace();
        } catch (ServiceResponseException e) {
            e.printStackTrace();
            System.out.println(e.getHttpStatusCode());
            System.out.println(e.getRequestId());
            System.out.println(e.getErrorCode());
            System.out.println(e.getErrorMsg());
        }
    }
}
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# coding: utf-8

import os
from huaweicloudsdkcore.auth.credentials import BasicCredentials
from huaweicloudsdkkms.v2.region.kms_region import KmsRegion
from huaweicloudsdkcore.exceptions import exceptions
from huaweicloudsdkkms.v2 import *

if __name__ == "__main__":
    # The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
    # In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
    ak = os.environ["CLOUD_SDK_AK"]
    sk = os.environ["CLOUD_SDK_SK"]
    projectId = "{project_id}"

    credentials = BasicCredentials(ak, sk, projectId)

    client = KmsClient.new_builder() \
        .with_credentials(credentials) \
        .with_region(KmsRegion.value_of("<YOUR REGION>")) \
        .build()

    try:
        request = DeriveSharedSecretRequest()
        request.body = DeriveSharedSecretRequestBody(
            public_key="MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE4UPptf7NVo2H+8Mz1V1dMz9x+DGdQSFxwLsqkUSXy4XNgs6bnxMtUB3WuI9GGzIYw21R/+w4lJvNDxYjd/Q1sQ==",
            key_agreement_algorithm="ECDH",
            key_id="f1b8b45f-9f87-43e2-b00c-8a4ca6eb1e39"
        )
        response = client.derive_shared_secret(request)
        print(response)
    except exceptions.ClientRequestException as e:
        print(e.status_code)
        print(e.request_id)
        print(e.error_code)
        print(e.error_msg)
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package main

import (
	"fmt"
	"github.com/huaweicloud/huaweicloud-sdk-go-v3/core/auth/basic"
    kms "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/kms/v2"
	"github.com/huaweicloud/huaweicloud-sdk-go-v3/services/kms/v2/model"
    region "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/kms/v2/region"
)

func main() {
    // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
    // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
    ak := os.Getenv("CLOUD_SDK_AK")
    sk := os.Getenv("CLOUD_SDK_SK")
    projectId := "{project_id}"

    auth, err := basic.NewCredentialsBuilder().
        WithAk(ak).
        WithSk(sk).
        WithProjectId(projectId).
        SafeBuild()

    if err != nil {
        fmt.Println(err)
        return
    }

    hcClient, err := kms.KmsClientBuilder().
         WithRegion(region.ValueOf("<YOUR REGION>")).
         WithCredential(auth).
         SafeBuild()


    if err != nil {
        fmt.Println(err)
        return
    }

    client := kms.NewKmsClient(hcClient)

    request := &model.DeriveSharedSecretRequest{}
	request.Body = &model.DeriveSharedSecretRequestBody{
		PublicKey: "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE4UPptf7NVo2H+8Mz1V1dMz9x+DGdQSFxwLsqkUSXy4XNgs6bnxMtUB3WuI9GGzIYw21R/+w4lJvNDxYjd/Q1sQ==",
		KeyAgreementAlgorithm: model.GetDeriveSharedSecretRequestBodyKeyAgreementAlgorithmEnum().ECDH,
		KeyId: "f1b8b45f-9f87-43e2-b00c-8a4ca6eb1e39",
	}
	response, err := client.DeriveSharedSecret(request)
	if err == nil {
        fmt.Printf("%+v\n", response)
    } else {
        fmt.Println(err)
    }
}

For SDK sample code of more programming languages, see the Sample Code tab in API Explorer. SDK sample code can be automatically generated.

Status Codes

Status Code

Description

200

Request succeeded.

Error Codes

See Error Codes.