public String getMasterUserSecretKmsKeyId() {
        return this.masterUserSecretKmsKeyId;
    }
<p>
The Amazon Web Services KMS key identifier to encrypt a secret that is automatically generated and managed in
Amazon Web Services Secrets Manager.
</p>
<p>
This setting is valid only if the master user password is managed by RDS in Amazon Web Services Secrets Manager
for the DB instance.
</p>
<p>
The Amazon Web Services KMS key identifier is the key ARN, key ID, alias ARN, or alias name for the KMS key. To
use a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN.
</p>
<p>
If you don't specify <code>MasterUserSecretKmsKeyId</code>, then the <code>aws/secretsmanager</code> KMS key is
used to encrypt the secret. If the secret is in a different Amazon Web Services account, then you can't use the
<code>aws/secretsmanager</code> KMS key to encrypt the secret, and you must use a customer managed KMS key.
</p>
<p>
There is a default KMS key for your Amazon Web Services account. Your Amazon Web Services account has a different
default KMS key for each Amazon Web Services Region.
</p>

@return The Amazon Web Services KMS key identifier to encrypt a secret that is automatically generated and
        managed in Amazon Web Services Secrets Manager.</p>
        <p>
        This setting is valid only if the master user password is managed by RDS in Amazon Web Services Secrets
        Manager for the DB instance.
        </p>
        <p>
        The Amazon Web Services KMS key identifier is the key ARN, key ID, alias ARN, or alias name for the KMS
        key. To use a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN.
        </p>
        <p>
        If you don't specify <code>MasterUserSecretKmsKeyId</code>, then the <code>aws/secretsmanager</code> KMS
        key is used to encrypt the secret. If the secret is in a different Amazon Web Services account, then you
        can't use the <code>aws/secretsmanager</code> KMS key to encrypt the secret, and you must use a customer
        managed KMS key.
        </p>
        <p>
        There is a default KMS key for your Amazon Web Services account. Your Amazon Web Services account has a
        different default KMS key for each Amazon Web Services Region.
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/model/RestoreDBInstanceFromS3Request.java