SAML security policy rule which validates the signature (if present) on the {@link SAMLObject} which represents theSAML protocol message being processed.
If the message is not an instance of {@link SignableSAMLObject}, then no processing is performed. If signature validation is successful, and the SAML message context issuer was not previously authenticated, then the context's issuer authentication state will be set to true.
If an optional {@link Validator} for {@link Signature} objects is supplied, this validator will be used to validatethe XML Signature element prior to the actual cryptographic validation of the signature. This might for example be used to enforce certain signature profile requirements or to detect signatures upon which it would be unsafe to attempt cryptographic processing. When using the single argument constructuor form, the validator will default to {@link SAMLSignatureProfileValidator}.