ISO/IEC 11770 is concerned with the management of cryptographic keys. ISO/IEC 11770-2:2008 specifies a series of 13 mechanisms for establishing shared secret keys using symmetric cryptography. These mechanisms address three different environments for the establishment of shared secret keys: point-to-point key establishment schemes, mechanisms using a Key Distribution Centre (KDC), and techniques that use a Key Translation Centre (KTC). ISO/IEC 11770-2:2008 describes the content of messages which carry keying material or are necessary to set up the conditions under which the keying material can be established. This second edition is a technically revised version of the first edition: Mechanism 12 has been modified to address identified security shortcomings.