Creates an *alias* , or a friendly name, for an AWS Payment Cryptography key.

You can use an alias to identify a key in the console and when you call cryptographic operations such as [EncryptData](https://docs.aws.amazon.com/payment-cryptography/latest/DataAPIReference/API_EncryptData.html) or [DecryptData](https://docs.aws.amazon.com/payment-cryptography/latest/DataAPIReference/API_DecryptData.html) .

You can associate the alias with any key in the same AWS Region . Each alias is associated with only one key at a time, but a key can have multiple aliases. You can't create an alias without a key. The alias must be unique in the account and AWS Region , but you can create another alias with the same name in a different AWS Region .

To change the key that's associated with the alias, call [UpdateAlias](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_UpdateAlias.html) . To delete the alias, call [DeleteAlias](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_DeleteAlias.html) . These operations don't affect the underlying key. To get the alias that you created, call [ListAliases](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_ListAliases.html) .

*Cross-account use* : This operation can't be used across different AWS accounts.

*Related operations:*

- [DeleteAlias](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_DeleteAlias.html)
- [GetAlias](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_GetAlias.html)
- [ListAliases](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_ListAliases.html)
- [UpdateAlias](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_UpdateAlias.html)

CfnAlias

A friendly name that you can use to refer to a key. The value must begin with `alias/` .

> Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in AWS CloudTrail logs and other output.

aliasName

The `KeyARN` of the key associated with the alias.

keyArn

Creates an AWS Payment Cryptography key, a logical representation of a cryptographic key, that is unique in your account and AWS Region .

You use keys for cryptographic functions such as encryption and decryption.

In addition to the key material used in cryptographic operations, an AWS Payment Cryptography key includes metadata such as the key ARN, key usage, key origin, creation date, description, and key state.

When you create a key, you specify both immutable and mutable data about the key. The immutable data contains key attributes that define the scope and cryptographic operations that you can perform using the key, for example key class (example: `SYMMETRIC_KEY` ), key algorithm (example: `TDES_2KEY` ), key usage (example: `TR31_P0_PIN_ENCRYPTION_KEY` ) and key modes of use (example: `Encrypt` ). AWS Payment Cryptography binds key attributes to keys using key blocks when you store or export them. AWS Payment Cryptography stores the key contents wrapped and never stores or transmits them in the clear.

For information about valid combinations of key attributes, see [Understanding key attributes](https://docs.aws.amazon.com/payment-cryptography/latest/userguide/keys-validattributes.html) in the *AWS Payment Cryptography User Guide* . The mutable data contained within a key includes usage timestamp and key deletion timestamp and can be modified after creation.

You can use the `CreateKey` operation to generate an ECC (Elliptic Curve Cryptography) key pair used for establishing an ECDH (Elliptic Curve Diffie-Hellman) key agreement between two parties. In the ECDH key agreement process, both parties generate their own ECC key pair with key usage K3 and exchange the public keys. Each party then use their private key, the received public key from the other party, and the key derivation parameters including key derivation function, hash algorithm, derivation data, and key algorithm to derive a shared key.

To maintain the single-use principle of cryptographic keys in payments, ECDH derived keys should not be used for multiple purposes, such as a `TR31_P0_PIN_ENCRYPTION_KEY` and `TR31_K1_KEY_BLOCK_PROTECTION_KEY` . When creating ECC key pairs in AWS Payment Cryptography you can optionally set the `DeriveKeyUsage` parameter, which defines the key usage bound to the symmetric key that will be derived using the ECC key pair.

*Cross-account use* : This operation can't be used across different AWS accounts.

*Related operations:*

- [DeleteKey](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_DeleteKey.html)
- [GetKey](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_GetKey.html)
- [ListKeys](https://docs.aws.amazon.com/payment-cryptography/latest/APIReference/API_ListKeys.html)

CfnKey

Specifies whether the key is exportable.

This data is immutable after the key is created.

exportable

The role of the key, the algorithm it supports, and the cryptographic operations allowed with the key.

This data is immutable after the key is created.

keyAttributes

The cryptographic usage of an ECDH derived key as deﬁned in section A.5.2 of the TR-31 spec.

deriveKeyUsage

enabled

The algorithm that AWS Payment Cryptography uses to calculate the key check value (KCV).

It is used to validate the key integrity.

For TDES keys, the KCV is computed by encrypting 8 bytes, each with value of zero, with the key to be checked and retaining the 3 highest order bytes of the encrypted result. For AES keys, the KCV is computed using a CMAC algorithm where the input data is 16 bytes of zero and retaining the 3 highest order bytes of the encrypted result.

keyCheckValueAlgorithm

The list of AWS Regions to remove from the key's replication configuration.

The key will no longer be available for cryptographic operations in these regions after removal. Ensure no active operations depend on the key in these regions before removal.

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