GenerateDataKeyPairWithoutPlaintext
Generates a unique asymmetric data key pair. The
GenerateDataKeyPairWithoutPlaintext
operation returns a plaintext public key
and a copy of the private key that is encrypted under the symmetric CMK you specify.
Unlike
GenerateDataKeyPair, this operation does not return a plaintext private
key.
To generate a data key pair, you must specify a symmetric customer master key (CMK)
to
encrypt the private key in the data key pair. You cannot use an asymmetric CMK or
a CMK in a
custom key store. To get the type and origin of your CMK, use the KeySpec
field
in the DescribeKey response.
You can use the public key that GenerateDataKeyPairWithoutPlaintext
returns
to encrypt data or verify a signature outside of AWS KMS. Then, store the encrypted
private key
with the data. When you are ready to decrypt data or sign a message, you can use the
Decrypt operation to decrypt the encrypted private key.
GenerateDataKeyPairWithoutPlaintext
returns a unique data key pair for each
request. The bytes in the key are not related to the caller or CMK that is used to
encrypt the
private key. The public key is a DER-encoded X.509 SubjectPublicKeyInfo, as specified
in
RFC 5280
You can use the optional encryption context to add additional security to the encryption
operation. If you specify an EncryptionContext
, you must specify the same
encryption context (a case-sensitive exact match) when decrypting the encrypted data
key.
Otherwise, the request to decrypt fails with an InvalidCiphertextException
. For more information, see Encryption Context in the
AWS Key Management Service Developer Guide.
The CMK that you use for this operation must be in a compatible key state. For details, see Key state: Effect on your CMK in the AWS Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a CMK in a different AWS account, specify
the key ARN or alias ARN in the value of the KeyId
parameter.
Required permissions: kms:GenerateDataKeyPairWithoutPlaintext (key policy)
Related operations:
Request Syntax
{
"EncryptionContext": {
"string
" : "string
"
},
"GrantTokens": [ "string
" ],
"KeyId": "string
",
"KeyPairSpec": "string
"
}
Request Parameters
For information about the parameters that are common to all actions, see Common Parameters.
The request accepts the following data in JSON format.
In the following list, the required parameters are described first.
- KeyId
-
Specifies the CMK that encrypts the private key in the data key pair. You must specify a symmetric CMK. You cannot use an asymmetric CMK or a CMK in a custom key store. To get the type and origin of your CMK, use the DescribeKey operation.
To specify a CMK, use its key ID, Amazon Resource Name (ARN), alias name, or alias ARN. When using an alias name, prefix it with
"alias/"
. To specify a CMK in a different AWS account, you must use the key ARN or alias ARN.For example:
-
Key ID:
1234abcd-12ab-34cd-56ef-1234567890ab
-
Key ARN:
arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
-
Alias name:
alias/ExampleAlias
-
Alias ARN:
arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias
To get the key ID and key ARN for a CMK, use ListKeys or DescribeKey. To get the alias name and alias ARN, use ListAliases.
Type: String
Length Constraints: Minimum length of 1. Maximum length of 2048.
Required: Yes
-
- KeyPairSpec
-
Determines the type of data key pair that is generated.
The AWS KMS rule that restricts the use of asymmetric RSA CMKs to encrypt and decrypt or to sign and verify (but not both), and the rule that permits you to use ECC CMKs only to sign and verify, are not effective outside of AWS KMS.
Type: String
Valid Values:
RSA_2048 | RSA_3072 | RSA_4096 | ECC_NIST_P256 | ECC_NIST_P384 | ECC_NIST_P521 | ECC_SECG_P256K1
Required: Yes
- EncryptionContext
-
Specifies the encryption context that will be used when encrypting the private key in the data key pair.
An encryption context is a collection of non-secret key-value pairs that represents additional authenticated data. When you use an encryption context to encrypt data, you must specify the same (an exact case-sensitive match) encryption context to decrypt the data. An encryption context is optional when encrypting with a symmetric CMK, but it is highly recommended.
For more information, see Encryption Context in the AWS Key Management Service Developer Guide.
Type: String to string map
Required: No
- GrantTokens
-
A list of grant tokens.
Use a grant token when your permission to call this operation comes from a new grant that has not yet achieved eventual consistency. For more information, see Grant token and Using a grant token in the AWS Key Management Service Developer Guide.
Type: Array of strings
Array Members: Minimum number of 0 items. Maximum number of 10 items.
Length Constraints: Minimum length of 1. Maximum length of 8192.
Required: No
Response Syntax
{
"KeyId": "string",
"KeyPairSpec": "string",
"PrivateKeyCiphertextBlob": blob,
"PublicKey": blob
}
Response Elements
If the action is successful, the service sends back an HTTP 200 response.
The following data is returned in JSON format by the service.
- KeyId
-
The Amazon Resource Name (key ARN) of the CMK that encrypted the private key.
Type: String
Length Constraints: Minimum length of 1. Maximum length of 2048.
- KeyPairSpec
-
The type of data key pair that was generated.
Type: String
Valid Values:
RSA_2048 | RSA_3072 | RSA_4096 | ECC_NIST_P256 | ECC_NIST_P384 | ECC_NIST_P521 | ECC_SECG_P256K1
- PrivateKeyCiphertextBlob
-
The encrypted copy of the private key. When you use the HTTP API or the AWS CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
Type: Base64-encoded binary data object
Length Constraints: Minimum length of 1. Maximum length of 6144.
- PublicKey
-
The public key (in plaintext).
Type: Base64-encoded binary data object
Length Constraints: Minimum length of 1. Maximum length of 8192.
Errors
For information about the errors that are common to all actions, see Common Errors.
- DependencyTimeoutException
-
The system timed out while trying to fulfill the request. The request can be retried.
HTTP Status Code: 500
- DisabledException
-
The request was rejected because the specified CMK is not enabled.
HTTP Status Code: 400
- InvalidGrantTokenException
-
The request was rejected because the specified grant token is not valid.
HTTP Status Code: 400
- InvalidKeyUsageException
-
The request was rejected for one of the following reasons:
-
The
KeyUsage
value of the CMK 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 CMK
(CustomerMasterKeySpec
).
For encrypting, decrypting, re-encrypting, and generating data keys, the
KeyUsage
must beENCRYPT_DECRYPT
. For signing and verifying, theKeyUsage
must beSIGN_VERIFY
. To find theKeyUsage
of a CMK, use the DescribeKey operation.To find the encryption or signing algorithms supported for a particular CMK, use the DescribeKey operation.
HTTP Status Code: 400
-
- KeyUnavailableException
-
The request was rejected because the specified CMK was not available. You can retry the request.
HTTP Status Code: 500
- KMSInternalException
-
The request was rejected because an internal exception occurred. The request can be retried.
HTTP Status Code: 500
- KMSInvalidStateException
-
The request was rejected because the state of the specified resource is not valid for this request.
For more information about how key state affects the use of a CMK, see How Key State Affects Use of a Customer Master Key in the AWS Key Management Service Developer Guide .
HTTP Status Code: 400
- NotFoundException
-
The request was rejected because the specified entity or resource could not be found.
HTTP Status Code: 400
- UnsupportedOperationException
-
The request was rejected because a specified parameter is not supported or a specified resource is not valid for this operation.
HTTP Status Code: 400
See Also
For more information about using this API in one of the language-specific AWS SDKs, see the following: