Signed login Assertion is mandatory for the Assertion verification by Artifactory. Any SAML response with unsigned assertion would cause a signature failure with signature null exception.
An SAML response with a signed signature assertion looks like:
<saml:Assertion xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" ID="pfxf96a4279-2b09-3c97-29a0-6ac11e04bfa8" Version="2.0" IssueInstant="2014-07-17T01:01:48Z">
---->The signed signature must be here under SAML assertion element
You may refer to here for more examples of how different saml response looks like.
User need to modify settings on their SAML IDP to provide a signed signature.
Note that Encrypted Assertion and Signed Logout are currently unsupported by Artifactory