Method and apparatus for securing programming data of a programmable device

A programmable integrated circuit device, comprising:

• an input for configuration data for the programmable integrated circuit device;
• and
• programming control circuitry operable to:
• derive a current signature from the configuration data;
• determine whether the configuration data includes an initial set of configuration data for the programmable integrated circuit device or an additional set of configuration data for the same programmable integrated circuit device;
• when the configuration data is determined to include the initial set of configuration data, compare the current signature to a signature stored in a nonvolatile signature storage of the programmable integrated circuit device and configure the programmable integrated circuit device according to the configuration data only when the current signature matches the signature stored in the nonvolatile signature storage;
• and
• when the configuration data is determined to include the additional set of configuration data, compare the current signature to a signature stored in a volatile signature storage of the programmable integrated circuit device and configure the programmable integrated circuit device according to the configuration data only when the current signature matches the signature of the volatile signature storage.

A method for configuring a programmable integrated circuit device using a bitstream, comprising:

• determining whether the bitstream includes an initial bitstream for the programmable integrated circuit device or a follow-on bitstream for the same programmable integrated circuit device;
• when the bitstream is determined to include the initial bitstream, comparing a current signature derived from the bitstream with a signature stored in a nonvolatile signature storage and loading the bitstream in the programmable integrated circuit device only when the current signature matches the signature stored in the nonvolatile signature storage;
• and
• when the bitstream is determined to include the follow-on bitstream, comparing a current signature derived from the bitstream with a signature stored in a volatile signature storage and loading the bitstream in the programmable integrated circuit device only when the current signature matches the signature stored in the volatile signature storage.