Cloud Key Management Service (KMS) C++ Client Library
An idiomatic C++ client library for Cloud Key Management Service (KMS), a service that manages keys and performs cryptographic operations in a central cloud service, for direct use by other cloud resources and applications.
While this library is GA, please note Google Cloud C++ client libraries do not follow Semantic Versioning.
Quickstart
The following shows the code that you'll run in the google/cloud/kms/quickstart/ directory, which should give you a taste of the KMS C++ client library API.
This library offers multiple *Client classes, which are listed below. Each one of these classes exposes all the RPCs for a service as member functions of the class. This library groups multiple services because they are part of the same product or are often used together. A typical example may be the administrative and data plane operations for a single product.
The library also has other classes that provide helpers, configuration parameters, and infrastructure to mock the *Client classes when testing your application.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis webpage provides documentation for the Cloud Key Management Service (KMS) C++ Client Library, which facilitates managing keys and performing cryptographic operations within Google Cloud.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version of the library is 2.37.0-rc, and the provided list shows previous available versions dating back to version 2.10.1.\u003c/p\u003e\n"],["\u003cp\u003eThe library includes several client classes, such as \u003ccode\u003eKeyDashboardServiceClient\u003c/code\u003e, \u003ccode\u003eKeyTrackingServiceClient\u003c/code\u003e, \u003ccode\u003eEkmServiceClient\u003c/code\u003e, and \u003ccode\u003eKeyManagementServiceClient\u003c/code\u003e, that expose RPCs for different KMS services.\u003c/p\u003e\n"],["\u003cp\u003eWhile the library is generally available (GA), it's crucial to note that Google Cloud C++ client libraries do not follow Semantic Versioning practices.\u003c/p\u003e\n"],["\u003cp\u003eThe library also provides information on error handling, overriding default endpoints and credentials, retry and backoff policies, and environment variables for configuration.\u003c/p\u003e\n"]]],[],null,["Version 2.16.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/kms/latest)\n- [2.41.0](/cpp/docs/reference/kms/2.41.0)\n- [2.40.0](/cpp/docs/reference/kms/2.40.0)\n- [2.39.0](/cpp/docs/reference/kms/2.39.0)\n- [2.38.0](/cpp/docs/reference/kms/2.38.0)\n- [2.37.0](/cpp/docs/reference/kms/2.37.0)\n- [2.36.0](/cpp/docs/reference/kms/2.36.0)\n- [2.35.0](/cpp/docs/reference/kms/2.35.0)\n- [2.34.0](/cpp/docs/reference/kms/2.34.0)\n- [2.33.0](/cpp/docs/reference/kms/2.33.0)\n- [2.32.0](/cpp/docs/reference/kms/2.32.0)\n- [2.31.0](/cpp/docs/reference/kms/2.31.0)\n- [2.30.0](/cpp/docs/reference/kms/2.30.0)\n- [2.29.0](/cpp/docs/reference/kms/2.29.0)\n- [2.28.0](/cpp/docs/reference/kms/2.28.0)\n- [2.27.0](/cpp/docs/reference/kms/2.27.0)\n- [2.26.0](/cpp/docs/reference/kms/2.26.0)\n- [2.25.1](/cpp/docs/reference/kms/2.25.1)\n- [2.24.0](/cpp/docs/reference/kms/2.24.0)\n- [2.23.0](/cpp/docs/reference/kms/2.23.0)\n- [2.22.1](/cpp/docs/reference/kms/2.22.1)\n- [2.21.0](/cpp/docs/reference/kms/2.21.0)\n- [2.20.0](/cpp/docs/reference/kms/2.20.0)\n- [2.19.0](/cpp/docs/reference/kms/2.19.0)\n- [2.18.0](/cpp/docs/reference/kms/2.18.0)\n- [2.17.0](/cpp/docs/reference/kms/2.17.0)\n- [2.16.0](/cpp/docs/reference/kms/2.16.0)\n- [2.15.1](/cpp/docs/reference/kms/2.15.1)\n- [2.14.0](/cpp/docs/reference/kms/2.14.0)\n- [2.13.0](/cpp/docs/reference/kms/2.13.0)\n- [2.12.0](/cpp/docs/reference/kms/2.12.0)\n- [2.11.0](/cpp/docs/reference/kms/2.11.0)\n- [2.10.1](/cpp/docs/reference/kms/2.10.1) \n\nCloud Key Management Service (KMS) C++ Client Library\n=====================================================\n\nAn idiomatic C++ client library for [Cloud Key Management Service (KMS)](https://cloud.google.com/kms/), a service that manages keys and performs cryptographic operations in a central cloud service, for direct use by other cloud resources and applications.\n\nWhile this library is **GA** , please note Google Cloud C++ client libraries do **not** follow [Semantic Versioning](https://semver.org/).\n\n### Quickstart\n\nThe following shows the code that you'll run in the `google/cloud/kms/quickstart/` directory, which should give you a taste of the KMS C++ client library API. \n\n #include \"google/cloud/kms/v1/key_management_client.h\"\n #include \"google/cloud/project.h\"\n #include \u003ciostream\u003e\n\n int main(int argc, char* argv[]) try {\n if (argc != 3) {\n std::cerr \u003c\u003c \"Usage: \" \u003c\u003c argv[0] \u003c\u003c \" project-id location-id\\n\";\n return 1;\n }\n\n namespace kms = ::google::cloud::kms_v1;\n auto client = kms::KeyManagementServiceClient(\n kms::MakeKeyManagementServiceConnection());\n\n auto const parent =\n std::string{\"projects/\"} + argv[1] + \"/locations/\" + argv[2];\n for (auto r : client.ListKeyRings(parent)) {\n if (!r) throw std::move(r).status();\n std::cout \u003c\u003c r-\u003eDebugString() \u003c\u003c \"\\n\";\n }\n\n return 0;\n } catch (google::cloud::Status const& status) {\n std::cerr \u003c\u003c \"google::cloud::Status thrown: \" \u003c\u003c status \u003c\u003c \"\\n\";\n return 1;\n }\n\n### Main classes\n\nThis library offers multiple `*Client` classes, which are listed below. Each one of these classes exposes all the RPCs for a service as member functions of the class. This library groups multiple services because they are part of the same product or are often used together. A typical example may be the administrative and data plane operations for a single product.\n\nThe library also has other classes that provide helpers, configuration parameters, and infrastructure to mock the `*Client` classes when testing your application.\n\n- [`kms_inventory_v1::KeyDashboardServiceClient`](/cpp/docs/reference/kms/2.16.0/classgoogle_1_1cloud_1_1kms__inventory__v1_1_1KeyDashboardServiceClient)\n- [`kms_inventory_v1::KeyTrackingServiceClient`](/cpp/docs/reference/kms/2.16.0/classgoogle_1_1cloud_1_1kms__inventory__v1_1_1KeyTrackingServiceClient)\n- [`kms_v1::EkmServiceClient`](/cpp/docs/reference/kms/2.16.0/classgoogle_1_1cloud_1_1kms__v1_1_1EkmServiceClient)\n- [`kms_v1::KeyManagementServiceClient`](/cpp/docs/reference/kms/2.16.0/classgoogle_1_1cloud_1_1kms__v1_1_1KeyManagementServiceClient)\n\n### More Information\n\n- [Error Handling](https://cloud.google.com/cpp/docs/reference/common/latest/common-error-handling.html) - describes how the library reports errors.\n- [How to Override the Default Endpoint](/cpp/docs/reference/kms/2.16.0/kms-override-endpoint) - describes how to override the default endpoint.\n- [How to Override the Authentication Credentials](/cpp/docs/reference/kms/2.16.0/kms-override-authentication) - describes how to change the authentication credentials used by the library.\n- [Override Retry, Backoff, and Idempotency Policies](/cpp/docs/reference/kms/2.16.0/kms-override-retry) - describes how to change the default retry policies.\n- [Environment Variables](/cpp/docs/reference/kms/2.16.0/kms-env) - describes environment variables that can configure the behavior of the library."]]