In electronic commerce, like elsewhere, certain types of messages are inherently more sensitive than others. For example, a contract acceptance is more sensitive than a notice of goods delivery. One requires more integrity and assurance. One will be retained, the other discarded. In the paper-based world, signatures provide a degree of assurance for the more important messages. The means by which the handwritten signature concept can be translated into the new electronic medium is discussed. Cryptologic techniques (such as "digital signatures") may be employed to obtain similar assurances in an electronic form. The author discusses digital signatures and legal signatures. >