Authentication of an unknown party in a secure computer communication may be performed even without consulting a public whitelist of trusted parties. A digital certificate from an unknown party not authenticated by a trusted certificate authority may be locally processed to determine if the digital certificate is a trusted, non-trusted, or unknown digital certificate. For example, a model may be created by training a support vector machine to classify a digital certificate. The model may be provided to a computer involved in secure computer communication. The computer may receive an incoming digital certificate, extract fields from the incoming digital certificate, and take a hash of the extracted fields perform input data that may be employed by the model to determine if the incoming digital certificate is a trusted, non-trusted, or unknown digital certificate.