keyId 
  Identifies the asymmetric KMS key that includes the public key.
To specify a KMS key, use its key ID, key ARN, alias name, or alias ARN. When using an alias name, prefix it with "alias/". To specify a KMS key in a different Amazon Web Services 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 KMS key, use ListKeys or DescribeKey. To get the alias name and alias ARN, use ListAliases.