Techniques for computer security, and more specifically timestamp-based key generation techniques, are described. Some implementations provide a table of key generation processes that is shared as a secret between a first computing system and a second computing system, both of which have synchronized clocks. Both computing systems use the same technique for selecting a key generation process from the table, such as based on a random number generator seeded with a timestamp. Since the computing systems have synchronized clocks, they both select and use the same key generation process, thereby generating the same encryption key without the need to communicate the key from one system to another. Furthermore, both computing systems may synchronize their clocks to a private time server that maintains a clock that runs faster or slower than standard time. Security is maintained by one or more of restricting access to the time server, using secret key generation processes, and/or using a secret random number generator.