public void setPreSharedKey(String preSharedKey) {
        this.preSharedKey = preSharedKey;
    }
<p>
The pre-shared key (PSK) to establish initial authentication between the virtual private gateway and customer
gateway.
</p>
<p>
Constraints: Allowed characters are alphanumeric characters, periods (.), and underscores (_). Must be between 8
and 64 characters in length and cannot start with zero (0).
</p>

@param preSharedKey
       The pre-shared key (PSK) to establish initial authentication between the virtual private gateway and
       customer gateway.</p>
       <p>
       Constraints: Allowed characters are alphanumeric characters, periods (.), and underscores (_). Must be
       between 8 and 64 characters in length and cannot start with zero (0).
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/VpnTunnelOptionsSpecification.java