The startup behavior of SRAM forms a unique pattern. This pattern is only available after SRAM power-up and is unique for each chip yet very persistent across a wide range of operating conditions. As some of the bits in the pattern are unstable, the pattern displays some variation i.e., it is fuzzy. An SRAM startup pattern is therefore a fuzzy identifier or fuzzy ID.

The fuzzy ID can be turned into a fixed identifier by matching it with a reference response. The FUZZY ID Server software records the initial fuzzy ID (e.g., 128 bytes) produced by a chip as a reference. It then extracts a fixed identifier (e.g., 64 bits) from the fuzzy ID. This fixed ID is a stable, collision-free identifier that can be used as a chip ID or serial number.

Later, the chip will produce a new fuzzy ID which is slightly different due to noise. The FUZZY ID software uses a scalable and efficient algorithm to convert it back to the same fixed ID.

Note that the exact length of the fuzzy and fixed ID depends on the requirements of the application.

Use Cases

Fuzzy IDs or SRAM PUF measurements recorded during manufacturing of devices can later be used for supply chain audits or counterfeit checks. The FUZZY ID output is like an invisible and tamper-resistant serial number embedded in a chip.
Using current technologies, devices without any non-volatile memory cannot store any identifier or any key. FUZZY ID can be used to identify such devices from their SRAM PUF fingerprint.
FUZZY ID can be combined with INTRINSIC ID’s QUIDDIKEY and BROADKEY secure key management modules to provide a full authentication solution without any non-volatile memory. In a first step, FUZZY ID is used to identify a chip. Once identified, the hub or host processor can send information to the chip that enables it to regenerate its inherent SRAM PUF key with QUIDDIKEY (Hardware) or BROADKEY (Software).

Key Benefits

  • Device identification from chip’s silicon fingerprint
  • Requires only small amount of (non-dedicated) SRAM
  • Very efficient and scalable conversion of a fuzzy ID to a fixed ID
  • Results in 64+ bit collision-free identifier
  • Reliable and robust technology
  • Compatible with QUIDDIKEY and BROADKEY for key management

Target Markets

  • Chip identification and authentication
  • Semiconductor manufacturing and supply chain management
  • IP and software protection
  • Supply chain protection and anti-counterfeiting
  • RFID tags
  • Embedded components