AWS services or capabilities described in AWS Documentation may vary by region/location. Click Getting Started with Amazon AWS to see specific differences applicable to the China (Beijing) Region.
Verifies a digital signature that was generated by the Sign operation.
Verification confirms that an authorized user signed the message with the specified
KMS key and signing algorithm, and the message hasn't changed since it was signed.
If the signature is verified, the value of the SignatureValid field in the
response is True. If the signature verification fails, the Verify operation
fails with an KMSInvalidSignatureException exception.
A digital signature is generated by using the private key in an asymmetric KMS key. The signature is verified by using the public key in the same asymmetric KMS key. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide.
To use the Verify operation, specify the same asymmetric KMS key, message,
and signing algorithm that were used to produce the signature. The message type does
not need to be the same as the one used for signing, but it must indicate whether
the value of the Message parameter should be hashed as part of the verification
process.
You can also verify the digital signature by using the public key of the KMS key outside
of KMS. Use the GetPublicKey operation to download the public key in the asymmetric
KMS key and then use the public key to verify the signature outside of KMS. The advantage
of using the Verify operation is that it is performed within KMS. As a result,
it's easy to call, the operation is performed within the FIPS boundary, it is logged
in CloudTrail, and you can use key policy and IAM policy to determine who is authorized
to use the KMS key to verify signatures.
To verify a signature outside of KMS with an SM2 public key (China Regions only),
you must specify the distinguishing ID. By default, KMS uses 1234567812345678
as the distinguishing ID. For more information, see Offline
verification with SM2 key pairs.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a different
Amazon Web Services account, specify the key ARN or alias ARN in the value of the
KeyId parameter.
Required permissions: kms:Verify (key policy)
Related operations: Sign
Eventual consistency: The KMS API follows an eventual consistency model. For more information, see KMS eventual consistency.
For .NET Core this operation is only available in asynchronous form. Please refer to VerifyAsync.
Namespace: Amazon.KeyManagementService
Assembly: AWSSDK.KeyManagementService.dll
Version: 3.x.y.z
public virtual VerifyResponse Verify( VerifyRequest request )
Container for the necessary parameters to execute the Verify service method.
| Exception | Condition |
|---|---|
| DependencyTimeoutException | The system timed out while trying to fulfill the request. You can retry the request. |
| DisabledException | The request was rejected because the specified KMS key is not enabled. |
| DryRunOperationException | The request was rejected because the DryRun parameter was specified. |
| InvalidGrantTokenException | The request was rejected because the specified grant token is not valid. |
| InvalidKeyUsageException | The request was rejected for one of the following reasons: The KeyUsage value of the KMS key is incompatible with the API operation. The encryption algorithm or signing algorithm specified for the operation is incompatible with the type of key material in the KMS key (KeySpec). For encrypting, decrypting, re-encrypting, and generating data keys, the KeyUsage must be ENCRYPT_DECRYPT. For signing and verifying messages, the KeyUsage must be SIGN_VERIFY. For generating and verifying message authentication codes (MACs), the KeyUsage must be GENERATE_VERIFY_MAC. To find the KeyUsage of a KMS key, use the DescribeKey operation. To find the encryption or signing algorithms supported for a particular KMS key, use the DescribeKey operation. |
| KeyUnavailableException | The request was rejected because the specified KMS key was not available. You can retry the request. |
| KMSInternalException | The request was rejected because an internal exception occurred. The request can be retried. |
| KMSInvalidSignatureException | The request was rejected because the signature verification failed. Signature verification fails when it cannot confirm that signature was produced by signing the specified message with the specified KMS key and signing algorithm. |
| KMSInvalidStateException | The request was rejected because the state of the specified resource is not valid for this request. This exceptions means one of the following: The key state of the KMS key is not compatible with the operation. To find the key state, use the DescribeKey operation. For more information about which key states are compatible with each KMS operation, see Key states of KMS keys in the Key Management Service Developer Guide. For cryptographic operations on KMS keys in custom key stores, this exception represents a general failure with many possible causes. To identify the cause, see the error message that accompanies the exception. |
| NotFoundException | The request was rejected because the specified entity or resource could not be found. |
This operation uses the public key in an elliptic curve (ECC) asymmetric key to verify a digital signature within AWS KMS.
var client = new AmazonKeyManagementServiceClient();
var response = client.Verify(new VerifyRequest
{
KeyId = "alias/ECC_signing_key", // The asymmetric KMS key to be used to verify the digital signature. This example uses an alias to identify the KMS key.
Message = new MemoryStream(<message to be verified>), // The message that was signed.
MessageType = "RAW", // Indicates whether the message is RAW or a DIGEST.
Signature = new MemoryStream(<binary data>), // The signature to be verified.
SigningAlgorithm = "ECDSA_SHA_384" // The signing algorithm to be used to verify the signature.
});
string keyId = response.KeyId; // The key ARN of the asymmetric KMS key that was used to verify the digital signature.
bool signatureValid = response.SignatureValid; // A value of 'true' Indicates that the signature was verified. If verification fails, the call to Verify fails.
string signingAlgorithm = response.SigningAlgorithm; // The signing algorithm that was used to verify the signature.
This operation uses the public key in an RSA asymmetric signing key pair to verify the digital signature of a message digest. Hashing a message into a digest before sending it to KMS lets you verify messages that exceed the 4096-byte message size limit. To indicate that the value of Message is a digest, use the MessageType parameter
var client = new AmazonKeyManagementServiceClient();
var response = client.Verify(new VerifyRequest
{
KeyId = "arn:aws:kms:us-east-2:111122223333:key/0987dcba-09fe-87dc-65ba-ab0987654321", // The asymmetric KMS key to be used to verify the digital signature. This example uses an alias to identify the KMS key.
Message = new MemoryStream(<message digest to be verified>), // The message that was signed.
MessageType = "DIGEST", // Indicates whether the message is RAW or a DIGEST. When it is RAW, KMS hashes the message before signing. When it is DIGEST, KMS skips the hashing step and signs the Message value.
Signature = new MemoryStream(<binary data>), // The signature to be verified.
SigningAlgorithm = "RSASSA_PSS_SHA_512" // The signing algorithm to be used to verify the signature.
});
string keyId = response.KeyId; // The key ARN of the asymmetric KMS key that was used to verify the digital signature.
bool signatureValid = response.SignatureValid; // A value of 'true' Indicates that the signature was verified. If verification fails, the call to Verify fails.
string signingAlgorithm = response.SigningAlgorithm; // The signing algorithm that was used to verify the signature.
.NET Framework:
Supported in: 4.5, 4.0, 3.5