Who can be trusted on the Web? These days, with identity theft seemingly rampant, it's more important than ever to take all possible measures to protect privacy and to shield personal information from those who might not have good intentions. Today, librarians also have to take reasonable precautions to ensure that the online services that they offer do not jeopardize their patrons' privacy. In this column, the author discusses available technologies for encryption and identity verification on the Web that will assist libraries in protecting their patrons' personal information. The use of Public Key Infrastructure (PKI) and digital certificates are two of the basic security components described.