Welcome
AWS Key Management Service (AWS KMS) is an encryption and key management web service. This guide describes the AWS KMS operations that you can call programmatically. For general information about AWS KMS, see the AWS Key Management Service Developer Guide.
Note
AWS KMS has replaced the term customer master key (CMK) with AWS KMS key and KMS key. The concept has not changed. To prevent breaking changes, AWS KMS is keeping some variations of this term.
AWS provides SDKs that consist of libraries and sample code for various programming
languages and platforms (Java, Ruby, .Net, macOS, Android, etc.). The SDKs provide a
convenient way to create programmatic access to AWS KMS and other AWS services. For example,
the SDKs take care of tasks such as signing requests (see below), managing errors, and
retrying requests automatically. For more information about the AWS SDKs, including how to
download and install them, see Tools for Amazon Web
Services
We recommend that you use the AWS SDKs to make programmatic API calls to AWS KMS.
If you need to use FIPS 140-2 validated cryptographic modules when communicating with AWS, use the FIPS endpoint in your preferred AWS Region. For more information about the available FIPS endpoints, see Service endpoints in the AWS Key Management Service topic of the Amazon Web Services General Reference.
All AWS KMS API calls must be signed and be transmitted using Transport Layer Security (TLS). AWS KMS recommends you always use the latest supported TLS version. Clients must also support cipher suites with Perfect Forward Secrecy (PFS) such as Ephemeral Diffie-Hellman (DHE) or Elliptic Curve Ephemeral Diffie-Hellman (ECDHE). Most modern systems such as Java 7 and later support these modes.
Signing Requests
Requests must be signed using an access key ID and a secret access key. We strongly recommend that you do not use your AWS account root access key ID and secret access key for everyday work. You can use the access key ID and secret access key for an IAM user or you can use the AWS Security Token Service (AWS STS) to generate temporary security credentials and use those to sign requests.
All AWS KMS requests must be signed with Signature Version 4.
Logging API Requests
AWS KMS supports AWS CloudTrail, a service that logs AWS API calls and related events for your AWS account and delivers them to an Amazon S3 bucket that you specify. By using the information collected by CloudTrail, you can determine what requests were made to AWS KMS, who made the request, when it was made, and so on. To learn more about CloudTrail, including how to turn it on and find your log files, see the AWS CloudTrail User Guide.
Additional Resources
For more information about credentials and request signing, see the following:
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AWS Security Credentials - This topic provides general information about the types of credentials used to access AWS.
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Temporary Security Credentials - This section of the IAM User Guide describes how to create and use temporary security credentials.
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Signature Version 4 Signing Process - This set of topics walks you through the process of signing a request using an access key ID and a secret access key.
Commonly Used API Operations
Of the API operations discussed in this guide, the following will prove the most useful for most applications. You will likely perform operations other than these, such as creating keys and assigning policies, by using the console.
This document was last published on April 23, 2024.
