A secure credential validation compares stored and received modified credentials, e.g., biometric credentials, such that the validating system does not have access to the unmodified credentials. A capture system and a credential validation system are operatively coupled to a network (e.g., the Internet). The credential validation system is configured to store a set of modified stored credentials associated with the principal, receive a set of modified received credentials, and perform a credential validation procedure to validate the modified received credentials, wherein the credential validation procedure performs a one-way consistency test to compare the modified stored credentials and the modified received credentials. The credential validation procedure employs one or more similarity measures, e.g., a weighted quorum of exact matches, a discrete N-ball (or “N-shell”) intersection, or a client-based algorithm with encryption.