Request quotas

AWS KMS establishes quotas for the number of API operations requested in each second. The request quotas differ with the API operation, the AWS Region, and other factors, such as the KMS key type. When you exceed an API request quota, AWS KMS throttles the request.

All AWS KMS request quotas are adjustable, except for the request quota for KMS keys in a custom key store. To request a quota increase, use the Service Quotas console or the RequestServiceQuotaIncrease operation. For instructions, see Requesting an AWS KMS quota increase. For details, see Requesting a quota increase in the Service Quotas User Guide. If Service Quotas for AWS KMS are not available in your AWS Region, please visit the AWS Support Center and create a case.

If you are exceeding the request quota for the GenerateDataKey operation, consider using the data key caching feature of the AWS Encryption SDK. Reusing data keys might reduce the frequency of your requests to AWS KMS.

In addition to request quotas, AWS KMS uses resource quotas to ensure capacity for all users. For details, see Resource quotas.

To view trends in your request rates, use the Service Quotas console. You can also create an Amazon CloudWatch alarm that alerts you when your request rate reaches a certain percentage of a quota value. For details, see Manage your AWS KMS API request rates using Service Quotas and Amazon CloudWatch in the AWS Security Blog.

Request quotas for each AWS KMS API operation

This table lists the Service Quotas quota code and the default value for each AWS KMS request quota.

Note

You might need to scroll horizontally or vertically to see all of the data in this table.

Quota name	Default value (per second)
Cryptographic operations (symmetric) request rate Applies to: Decrypt Encrypt GenerateDataKey GenerateDataKeyWithoutPlaintext GenerateMac GenerateRandom ReEncrypt VerifyMac	These shared quotas vary with the AWS Region and the type of KMS key used in the request. Each quota is calculated separately. 5,500 (shared) 10,000 (shared) in the following Regions: US East (Ohio), us-east-2 Asia Pacific (Singapore), ap-southeast-1 Asia Pacific (Sydney), ap-southeast-2 Asia Pacific (Tokyo), ap-northeast-1 Europe (Frankfurt), eu-central-1 Europe (London), eu-west-2 50,000 (shared) in the following Regions: US East (N. Virginia), us-east-1 US West (Oregon), us-west-2 Europe (Ireland), eu-west-1 Custom key stores quota (symmetric KMS keys): 1,800 (shared) for each custom key store. For details, see Custom key store quota.
Cryptographic operations (RSA) request rate Applies to: Decrypt Encrypt ReEncrypt Sign Verify	500 (shared) for RSA KMS keys
Cryptographic operations (ECC) request rate Applies to: Sign Verify	300 (shared) for elliptic curve (ECC) KMS keys
Cryptographic operations (SM) request rate Applies to: Decrypt Encrypt ReEncrypt Sign Verify	300 (shared) for SM2 (China Regions only) KMS keys
CancelKeyDeletion request rate	5
ConnectCustomKeyStore request rate	5
CreateAlias request rate	5
CreateCustomKeyStore request rate	5
CreateGrant request rate	50
CreateKey request rate	5
DeleteAlias request rate	15
DeleteCustomKeyStore request rate	5
DeleteImportedKeyMaterial request rate	5
DescribeCustomKeyStores request rate	5
DescribeKey request rate	2000
DisableKey request rate	5
DisableKeyRotation request rate	5
DisconnectCustomKeyStore request rate	5
EnableKey request rate	5
EnableKeyRotation request rate	15
GenerateDataKeyPair (ECC_NIST_P256) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	25
GenerateDataKeyPair (ECC_NIST_P384) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	10
GenerateDataKeyPair (ECC_NIST_P521) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	5
GenerateDataKeyPair (ECC_SECG_P256K1) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	25
GenerateDataKeyPair (RSA_2048) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	1
GenerateDataKeyPair (RSA_3072) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	0.5 (1 in each 2-second interval)
GenerateDataKeyPair (RSA_4096) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	0.1 (1 in each 10-second interval)
GenerateDataKeyPair (SM2 — China Regions only) request rate Applies to: GenerateDataKeyPair GenerateDataKeyPairWithoutPlaintext	25
GetKeyPolicy request rate	1000
GetKeyRotationStatus request rate	1000
GetParametersForImport request rate	0.25 (1 in each 4-second interval)
GetPublicKey request rate	2000
ImportKeyMaterial request rate	5
ListAliases request rate	500
ListGrants request rate	100
ListKeyPolicies request rate	100
ListKeys request rate	500
ListResourceTags request rate	2000
ListRetirableGrants request rate	100
PutKeyPolicy request rate	15
ReplicateKey request rate A ReplicateKey operation counts as one ReplicateKey request in the primary key's Region and two CreateKey requests in the replica's Region. One of the CreateKey requests is a dry run to detect potential problems before creating the key.	5
RetireGrant request rate	30
RevokeGrant request rate	30
ScheduleKeyDeletion request rate	15
TagResource request rate	10
UntagResource request rate	5
UpdateAlias request rate	5
UpdateCustomKeyStore request rate	5
UpdateKeyDescription request rate	5
UpdatePrimaryRegion request rate An UpdatePrimaryRegion operation counts as two UpdatePrimaryRegion requests; one request in each of the two affected Regions.	5

Applying request quotas

When reviewing request quotas, keep in mind the following information.

• Request quotas apply to both customer managed keys and AWS managed keys. The use of AWS owned keys does not count against request quotas for your AWS account, even when they are used to protect resources in your account.

• Request quotas apply to requests sent to FIPS endpoints and non-FIPS endpoints. For a list of AWS KMS service endpoints, see AWS Key Management Service endpoints and quotas in the AWS General Reference.

• Throttling is based on all requests on KMS keys of all types in the Region. This total includes requests from all principals in the AWS account, including requests from AWS services on your behalf.

• Each request quota is calculated independently. For example, requests for the CreateKey operation have no effect on the request quota for the CreateAlias operation. If your CreateAlias requests are throttled, your CreateKey requests can still complete successfully.

• Although cryptographic operations share a quota, the shared quota is calculated independently of quotas for other operations. For example, calls to the Encrypt and Decrypt operations share a request quota, but that quota is independent of the quota for management operations, such as EnableKey. For example, in the Europe (London) Region, you can perform 10,000 cryptographic operations on symmetric KMS keys plus 5 EnableKey operations per second without being throttled.

Shared quotas for cryptographic operations

AWS KMS cryptographic operations share request quotas. You can request any combination of the cryptographic operations that are supported by the KMS key, just so the total number of cryptographic operations doesn't exceed the request quota for that type of KMS key. The exceptions are GenerateDataKeyPair and GenerateDataKeyPairWithoutPlaintext, which share a separate quota.

The quotas for different types of KMS keys are calculated independently. Each quota applies to all requests for these operations in the AWS account and Region with the given key type in each one-second interval.

• Cryptographic operations (symmetric) request rate is the shared request quota for cryptographic operations using symmetric KMS keys in an account and region. This quota applies to cryptographic operations with symmetric encryption keys and HMAC keys, which are also symmetric.

  For example, you might be using symmetric KMS keys in an AWS Region with a shared quota of 10,000 requests per second. When you make 7,000 GenerateDataKey requests per second and 2,000 Decrypt requests per second, AWS KMS doesn't throttle your requests. However, when you make 9,500 GenerateDataKey requests and 1,000 Encrypt and requests per second, AWS KMS throttles your requests because they exceed the shared quota.

• Cryptographic operations (RSA) request rate is the shared request quota for cryptographic operations using RSA asymmetric KMS keys.

  For example, with a request quota of 500 operations per second, you can make 200 Encrypt requests and 100 Decrypt requests with RSA KMS keys that can encrypt and decrypt, plus 50 Sign requests and 150 Verify requests with RSA KMS keys that can sign and verify.

• Cryptographic operations (ECC) request rate is the shared request quota for cryptographic operations using elliptic curve (ECC) asymmetric KMS keys.

  For example, with a request quota of 300 operations per second, you can make 100 Sign requests and 200 Verify requests with RSA KMS keys that can sign and verify.

• Cryptographic operations (SM — China Regions only) request rate is the shared request quota for cryptographic operations using SM asymmetric KMS keys.

  For example, with a request quota of 300 operations per second, you can make 100 Encrypt requests and 100 Decrypt requests with SM2 KMS keys that can encrypt and decrypt, plus 50 Sign requests and 50 Verify requests with SM2 KMS keys that can sign and verify.

The quotas for different key types are also calculated independently. For example, in the Asia Pacific (Singapore) Region, if you use both symmetric and asymmetric KMS keys, you can make up to 10,000 calls per second with symmetric KMS keys (including HMAC keys) plus up to 500 additional calls per second with your RSA asymmetric KMS keys, plus up to 300 additional requests per second with your ECC-based KMS keys.

API requests made on your behalf

You can make API requests directly or by using an integrated AWS service that makes API requests to AWS KMS on your behalf. The quota applies to both kinds of requests.

For example, you might store data in Amazon S3 using server-side encryption with a KMS key (SSE-KMS). Each time you upload or download an S3 object that's encrypted with SSE-KMS, Amazon S3 makes a GenerateDataKey (for uploads) or Decrypt (for downloads) request to AWS KMS on your behalf. These requests count toward your quota, so AWS KMS throttles the requests if you exceed a combined total of 5,500 (or 10,000 or 50,000 depending upon your AWS Region) uploads or downloads per second of S3 objects encrypted with SSE-KMS.

Cross-account requests

When an application in one AWS account uses a KMS key owned by a different account, it's known as a cross-account request. For cross-account requests, AWS KMS throttles the account that makes the requests, not the account that owns the KMS key. For example, if an application in account A uses a KMS key in account B, the KMS key use applies only to the quotas in account A.

Custom key store quota

AWS KMS custom key stores support only symmetric encryption KMS keys. The KMS keys in each custom key store share a Cryptographic operations (symmetric) request rate request quota of 1,800 operations per second. This quota is calculated separately for each custom key store.

However, not all operations use the quota equally. The GenerateDataKey, GenerateDataKeyWithoutPlaintext, and GenerateRandom operations use approximately three times as much of the per-second quota as the Encrypt, Decrypt, and ReEncrypt operations.

For example, if you are requesting only Encrypt and Decrypt operations, you can perform approximately 1,800 operations per second. If, instead, you request repeated GenerateDataKey operations, your performance might be closer to 600 operations per second. For applications patterns that consist of roughly equal numbers of GenerateDataKey and Decrypt operations, you can expect about 1,200 operations per second.

The custom key store quota is not adjustable. You cannot increase it by using Service Quotas or by creating a case in AWS Support.

Note

If the AWS CloudHSM cluster that is associated with the custom key store is processing numerous commands, including those unrelated to the custom key store, you might get an AWS KMS ThrottlingException at a lower-than-expected rate. If this occurs, lower your request rate to AWS KMS, reduce the unrelated load, or use a dedicated AWS CloudHSM cluster for your custom key store.

AWS KMS also throttles cryptographic operations on KMS keys in custom key stores when there are no available PKCS11 sessions for the AWS CloudHSM cluster. These ThrottlingException instances typically occur during periods of high burst traffic when additional sessions are needed to service the traffic.