Decrypt - Amazon Key Management Service
Decrypt with a standard symmetric encryption key Decrypt failure with a standard symmetric encryption keyDecrypt with a KMS key in an Amazon CloudHSM key storeDecrypt with a KMS key in an external key storeDecrypt failure with a KMS key in an external key store
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Decrypt

These examples show Amazon CloudTrail log entries for the Decrypt operation.

The CloudTrail log entry for a Decrypt operation always includes the encryptionAlgorithm in the requestParameters even if the encryption algorithm wasn't specified in the request. The ciphertext in the request and the plaintext in the response are omitted.

Decrypt with a standard symmetric encryption key

The following is an example CloudTrail log entry for a Decrypt operation with a standard symmetric encryption key. 

{
    "eventVersion": "1.05",
    "userIdentity": {
        "type": "IAMUser",
        "principalId": "EX_PRINCIPAL_ID",
        "arn": "arn:aws:iam::111122223333:user/Alice",
        "accountId": "111122223333",
        "accessKeyId": "EXAMPLE_KEY_ID",
        "userName": "Alice"
    },
    "eventTime": "2020-07-27T22:58:24Z",
    "eventSource": "kms.amazonaws.com",
    "eventName": "Decrypt",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "192.0.2.0",
    "userAgent": "Amazon Internal",
    "requestParameters": {
        "encryptionAlgorithm": "SYMMETRIC_DEFAULT",
        "keyId": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab",
        "encryptionContext": {
            "Department": "Engineering",
            "Project": "Alpha"
        }        
    },
    "responseElements": null,
    "requestID": "12345126-30d5-4b28-98b9-9153da559963",
    "eventID": "abcde202-ba1a-467c-b4ba-f729d45ae521",
    "readOnly": true,
    "resources": [
        {
            "accountId": "111122223333",
            "type": "AWS::KMS::Key",
            "ARN": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab"
        }
    ],
    "eventType": "AwsApiCall",
    "recipientAccountId": "111122223333"
}

Decrypt failure with a standard symmetric encryption key

The following example CloudTrail log entry records a failed Decrypt operation with a standard symmetric encryption KMS key. The exception (errorCode) and error message (errorMessage) are included help you to resolve the error.

In this case, the symmetric encryption KMS key specified in the Decrypt request was not the symmetric encryption KMS key that was used to encrypt the data.

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "IAMUser",
        "principalId": "EX_PRINCIPAL_ID",
        "arn": "arn:aws:iam::111122223333:user/Alice",
        "accountId": "111122223333",
        "accessKeyId": "EXAMPLE_KEY_ID",
        "userName": "Alice"
    },
    "eventTime": "2022-11-24T18:57:43Z",
    "eventSource": "kms.amazonaws.com",
    "eventName": "Decrypt",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "192.0.2.0",
    "userAgent": "AWS Internal",
    "errorCode": "IncorrectKeyException"
    "errorMessage": "The key ID in the request does not identify a CMK that can perform this operation.",
    "requestParameters": {
        "encryptionAlgorithm": "SYMMETRIC_DEFAULT",
        "keyId": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab",
        "encryptionContext": {
            "Department": "Engineering",
            "Project": "Alpha"
        }        
    },
    "responseElements": null,
    "requestID": "22345126-30d5-4b28-98b9-9153da559963",
    "eventID": "abcde202-ba1a-467c-b4ba-f729d45ae521",
    "readOnly": true,
    "resources": [
        {
            "accountId": "111122223333",
            "type": "AWS::KMS::Key",
            "ARN": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab"
        }
    ],
    "eventType": "AwsApiCall",
    "recipientAccountId": "111122223333"
}

Decrypt with a KMS key in an Amazon CloudHSM key store

The following example CloudTrail log entry records a Decrypt operation with a KMS key in an Amazon CloudHSM key store. All log entries for cryptographic operations with a KMS key in a custom key store include an additionalEventData field with the customKeyStoreId. The additionalEventData isn't specified in the request.

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "IAMUser",
        "principalId": "EX_PRINCIPAL_ID",
        "arn": "arn:aws:iam::111122223333:user/Alice",
        "accountId": "111122223333",
        "accessKeyId": "EXAMPLE_KEY_ID",
        "userName": "Alice"
    },
    "eventTime": "2021-10-26T23:41:27Z",
    "eventSource": "kms.amazonaws.com",
    "eventName": "Decrypt",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "192.0.2.0",
    "requestParameters": {
        "encryptionAlgorithm": "SYMMETRIC_DEFAULT",
        "keyId": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab",
        "encryptionContext": {
            "Department": "Development",
            "Purpose": "Test"
        }
    },
    "responseElements": null,
    "additionalEventData": {
        "customKeyStoreId": "cks-1234567890abcdef0"
    },
    "requestID": "e1b881f8-2048-41f8-b6cc-382b7857ec61",
    "eventID": "a79603d5-4cde-46fc-819c-a7cf547b9df4",
    "readOnly": true,
    "resources": [
        {
            "accountId": "111122223333",
            "type": "AWS::KMS::Key",
            "ARN": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab"
        }
    ],
    "eventType": "AwsApiCall",
    "managementEvent": true,
    "recipientAccountId": "111122223333",
    "eventCategory": "Management"    
}

Decrypt with a KMS key in an external key store

The following example CloudTrail log entry records a Decrypt operation with a KMS key in an external key store. In addition to the customKeyStoreId, the additionalEventData field includes the external key ID (XksKeyId). The additionalEventData isn't specified in the request.

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "IAMUser",
        "principalId": "EX_PRINCIPAL_ID",
        "arn": "arn:aws:iam::111122223333:user/Alice",
        "accountId": "111122223333",
        "accessKeyId": "EXAMPLE_KEY_ID",
        "userName": "Alice"
    },
    "eventTime": "2022-11-24T00:26:58Z",
    "eventSource": "kms.amazonaws.com",
    "eventName": "Decrypt",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "AWS Internal",
    "requestParameters": {
        "encryptionAlgorithm": "SYMMETRIC_DEFAULT",
        "keyId": "arn:aws:kms:us-west-2:111122223333:key/0987dcba-09fe-87dc-65ba-ab0987654321",
        "encryptionContext": {
            "Department": "Engineering",
            "Purpose": "Test"
        }
    },
    "responseElements": null,
    "additionalEventData": {
        "customKeyStoreId": "cks-9876543210fedcba9",
        "xksKeyId": "abc01234567890fe"
    },
    "requestID": "f1b881f8-2048-41f8-b6cc-382b7857ec61",
    "eventID": "b79603d5-4cde-46fc-819c-a7cf547b9df4",
    "readOnly": true,
    "resources": [
        {
            "accountId": "111122223333",
            "type": "AWS::KMS::Key",
            "ARN": "arn:aws:kms:us-west-2:111122223333:key/0987dcba-09fe-87dc-65ba-ab0987654321"
        }
    ],
    "eventType": "AwsApiCall",
    "managementEvent": true,
    "recipientAccountId": "111122223333",
    "eventCategory": "Management"
}

Decrypt failure with a KMS key in an external key store

The following example CloudTrail log entry records a failed request for a Decrypt operation with a KMS key in an external key store. CloudWatch logs requests that fail, in addition to successful requests. When recording a failure, the CloudTrail log entry includes the exception (errorCode) and the accompanying error message (errorMessage).

If the failed request reached your external key store proxy, as in this example, you can use the requestId value to associate the failed request with a corresponding request your external key store proxy logs, if your proxy provides them.

For help with Decrypt requests in external key stores, see Decryption errors.

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "IAMUser",
        "principalId": "EX_PRINCIPAL_ID",
        "arn": "arn:aws:iam::111122223333:user/Alice",
        "accountId": "111122223333",
        "accessKeyId": "EXAMPLE_KEY_ID",
        "userName": "Alice"
    },
    "eventTime": "2022-11-24T00:26:58Z",
    "eventSource": "kms.amazonaws.com",
    "eventName": "Decrypt",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "AWS Internal",
    "userAgent": "AWS Internal",
    "errorCode": "KMSInvalidStateException",
    "errorMessage": "The external key store proxy rejected the request because the specified ciphertext or additional authenticated data is corrupted, missing, or otherwise invalid.",
    "requestParameters": {
        "encryptionAlgorithm": "SYMMETRIC_DEFAULT",
        "keyId": "arn:aws:kms:us-west-2:111122223333:key/0987dcba-09fe-87dc-65ba-ab0987654321",
        "encryptionContext": {
            "Department": "Engineering",
            "Purpose": "Test"
        }
    },
    "responseElements": null,
    "additionalEventData": {
        "customKeyStoreId": "cks-9876543210fedcba9",
        "xksKeyId": "abc01234567890fe"
    },
    "requestID": "f1b881f8-2048-41f8-b6cc-382b7857ec61",
    "eventID": "b79603d5-4cde-46fc-819c-a7cf547b9df4",
    "readOnly": true,
    "resources": [
        {
            "accountId": "111122223333",
            "type": "AWS::KMS::Key",
            "ARN": "arn:aws:kms:us-west-2:111122223333:key/0987dcba-09fe-87dc-65ba-ab0987654321"
        }
    ],
    "eventType": "AwsApiCall",
    "managementEvent": true,
    "recipientAccountId": "111122223333",
    "eventCategory": "Management"
}