A method and system for securely timestamping digital data is disclosed. A secure encryption key is provided within a timestamping module. The timestamping module comprises a processor for performing security functions with the secure encryption key. The processor is operable in a first mode wherein the secure encryption key is used for encryption operations and for test operations and in a second mode in which the secure encryption key is only used for timestamping operations. Once the processor performs a function with the secure encryption key in the second mode it is precluded from performing further functions in the first mode with the secure encryption key. After the processor has been placed in the second mode of operation a unique code for being embedded within timestamped digital data is generated. Data indicative of a real time a request for a timestamping operation has been received is then provided to the processor from a real time clock. Based on the data indicative of a real time a timestamp is generated using the secure encryption key. The timestamp is embedded within the digital data and the unique code is inserted within the digital data. The digital data with the inserted data therein are then encoded to form timestamped digital data. Upon receipt of the securely timestamped digital data the unique code is retrieved from the securely timestamped digital data in order to verify the authenticity of the time data.