Fix misleading comment with fingerprint hash weaker than a certificate verification

The reasoning of a fingerprint hash weaker than providing a certificate like a CA is wrong. 

A X509 signature of a certificate always uses a Hash like SHA1, SHA256, etc, which is then signed. E.g. 

 openssl1.1 x509 -text -in sp-test.pem 

    Signature Algorithm: ecdsa-with-SHA256

So these are as vulnerable to collision attacks as fingeprints.

Depending on the implementation of the fingerprint, there are other for not using them. E.g. some implementation ignore other problem with a certificate like validity or missing EKUs.

Author: schwabe

README.md

@@ -323,8 +323,8 @@ This is the ``settings.json`` file:
         /*
          *  Instead of using the whole X.509cert you can use a fingerprint in order to
          *  validate a SAMLResponse (but you still need the X.509cert to validate LogoutRequest and LogoutResponse using the HTTP-Redirect binding).
-         *  But take in mind that the fingerprint, is a hash, so at the end is open to a collision attack that can end on a signature validation bypass,
-         *  that why we don't recommend it use for production environments.
+         *  But take in mind that the algortithm for the fingerprint should be as strong as the algorithm in a normal certificate signature
+	 *  (e.g. SHA256 or strong)
          *
          *  (openssl x509 -noout -fingerprint -in "idp.crt" to generate it,
          *  or add for example the -sha256 , -sha384 or -sha512 parameter)