Abstract: An electronic lock, system and method for dynamic controlled access, without the lock communicating with or connected to a code server, are provided. The lock includes a locking mechanism, a clock, a microprocessor, and a memory storing a hash function and programmed instructions for the microprocessor to perform certain operations. The microprocessor and memory may be comprised in a microcontroller. When an access code is entered into the lock, the lock microcontroller hashes currently valid access start date/duration combinations with lock identifying data to return valid access codes. If the entered access code equals any of the valid access codes, the locking mechanism is opened. The lock identifying data may include data stored by a lock manufacturer and/or data created by a lock owner. Static access codes may also be programmed into the lock if desired. Caching of valid access codes may be used to reduce processing time.

Abstract: An electronic lock, system and method for dynamic controlled access, without the lock communicating with or connected to a code server, are provided. The lock includes a locking mechanism, a clock, a microprocessor, and a memory storing a hash function and programmed instructions for the microprocessor to perform certain operations. The microprocessor and memory may be comprised in a microcontroller. When an access code is entered into the lock, the lock microcontroller hashes currently valid access start date/duration combinations with lock identifying data to return valid access codes. If the entered access code equals any of the valid access codes, the locking mechanism is opened. The lock identifying data may include data stored by a lock manufacturer and/or data created by a lock owner. Static access codes may also be programmed into the lock if desired. Caching of valid access codes may be used to reduce processing time.