Keyless Encryption Schemes with Addressable Physical Unclonable Functions (PUFs)

Description

The technology is a keyless encryption scheme that uses addressable physically unclonable functions (PUFs) to generate ciphers that can only be decrypted by the same addressable PUFs. An image of the PUFs, stored in separate devices, can also be used. Through a handshake cycle, sets of addresses are generated to point in a set of cells in the PUFs as defined by their physical parameters. The addresses are used for a specific encryption and decryption cycle. The messages to encrypt, which are streams of bits, are segmented into blocks, whose numeric values are used to modify the values of the selected cells’ physical parameters. These modified values are reorganized randomly to form block ciphers, which are transmitted to the communicating party (e.g., server). The receiving party (e.g., client device) has independent access to the same values of the selected cells’ physical parameters, and the receiving party measures the differences between the original and the modified values of these parameters. Using the value differences, the receiving party calculates the values of the block bits, which were used to modify the physical parameter values. Thereby, the receiving party retrieves the original message. In these schemes, the size of the block ciphers is typically 1024-bit long. Multiple handshakes can be used to encrypt longer messages, segmented into blocks of various sizes. Using memristor-based PUFs, the schemes’ entropy can be enhanced because the value of each cell parameter is constantly adjustable.

Additional information