A device, system, and method are directed towards facilitating a registration of a user for a network service. In one embodiment, a server receives, from a user at a client device, user information including at least one text block. The server analyzes the text block to determine an authenticity value of the user information. The analysis may be based on the length of a lexicon of the text block, the size of a word such as the longest word in the text block, or the number of clauses in the text block. The analysis may be further based on expected values determined by such values in authentic text blocks of a similar nature. Based on the authenticity value, the system may allow the user to access the network service, disallow access to the network, allow conditional access, queue the registration application for further review, or take other actions.