A system and method that uses authentication inkblots to help computer system users first select and later recall authentication information from high entropy information spaces. An inkblot authentication module generates authentication inkblots from authentication inkblot seeds. On request, a security authority generates, stores and supplies an authentication inkblot seed set for a user. In response to an authentication inkblot, a user inputs one or more alphanumeric characters. The responses to one or more authentication inkblots serve as authentication information. A user-computable hash of the natural language description of the authentication inkblot is utilized to speed authentication information entry and provide for compatibility with conventional password-based authentication. Authentication with an authentication information match ratio of less than 100% is possible. Authentication inkblot generation methods are disclosed, as well as a detailed inkblot authentication protocol which makes it difficult for users to opt-out of high entropy authentication information generation.