Altera Corporation

David Edward Jefferson

Srinivas T Reddy

Richard G Cliff

Christopher F Lane

Andy Louie Lee

Keone Streicher

Juju Joyce

Martin Langhammer

Bruce B Pedersen

Manuel M Mejia

L Todd Cope

Cameron R McClintock

Triet M Nguyen

Ketan H Zaveri

Changsong Zhang

Joseph Huang

David Wolk Mendel

Kerry S Veenstra

Francis B Heile

Craig S Lytle

Nitin Prasad

Rina Raman

Vaughn Betz

James G Schleicher

Vikram Santurkar

David Lewis

Paul Leventis

Brian D Johnson

Jinyong Yuan

Wanli Chang

Yi-Wen Lin

Michael Chan

Robert R Bielby

Robert Richard Noel Bielby

Kurosu R Altaf

Hyun Mo Yi

David Cashman

John Henry Bui

Giles V Powell

Rahul Saini

Bruce B Pederson

Dan Mansur

Triet Nguyen

Circuits, methods, and apparatus that prevent detection and erasure of encoding or encryption keys. These encoding keys may be used to encode a configuration bitstream or other data for an FPGA or other device. An exemplary embodiment of the present invention masks a first key to form an encoding key in order to prevent detection of the first key. In a specific embodiment, the first key is encoded using a second key. The encoded key is used to encode a configuration bitstream or other data. The encoded key is stored on an FPGA or other device. When the device is to be configured, the encoded key is retrieved and used to decode the bitstream or other data. A further embodiment stores an encryption key in a one-time programmable memory (OTP) array to prevent its erasure or modification. The encoding key may be further obfuscated before storage.

FPGA configuration bitstream protection using multiple keys

Circuits, methods, and apparatus that prevent detection and erasure of a configuration bitstream or other data for an FPGA or other device. An exemplary embodiment of the present invention masks a user key in order to prevent its detection. In a specific embodiment, the user key is masked by software that performs a function on it a first number of times. The result is used to encrypt a configuration bitstream. The user key is also provided to an FPGA or other device, where the function is performed a second number of times and the result stored. When the device is configured, the result is retrieved, the function is performed on it the first number of times less the second number of times and then it is used to decrypt the configuration bitstream. A further embodiment uses a one-time programmable fuse (OTP) array to prevent erasure or modification.

FPGA configuration bitstream encryption using modified key

Circuits, methods, and apparatus that store and prevent modification or erasure of stored encoding keys, serial identification numbers, or other information. An encoding key stored with an embodiment of the present invention may be used to decode a configuration bitstream on an integrated circuit, such as an FPGA. A serial number may be used to track or authenticate an integrated circuit. Embodiments of the present invention store this information in a memory such as an SRAM, DRAM, EPROM, EEPROM, flash, fuse array, or other type of memory. In order to prevent its erasure or modification, write enable circuitry for the memory is then permanently disabled, and if the memory is volatile, a continuous power supply is provided. Further refinements verify that the write enable circuitry has been disabled before allowing the device to be configured or to be operable.

One-time programmable memories for key storage

A first set of configuration logic is configurable to provide a first port input clock signal for controlling input registers of a first port of a memory block. A second set of configuration logic is configurable to provide a second port input clock signal for controlling input registers of a second port of the memory block.

Flexible RAM clock enable

Integrated circuits with memory elements are provided. The memory elements may be arranged in an array. Data lines may be used to load data into the memory elements and may be used to read data from the memory elements. The memory elements may be used to store configuration data on a programmable logic device integrated circuit. Each memory element may have an output that supplies a programmable transistor gate with a static control signal. Data reading circuitry may be coupled to each data line to read data from an addressed memory element on that data line. The data reading circuitry for each data line may include a precharge transistor and an output latch. The output latch may contain cross-coupled inverters. An inwardly-directed inverter in the output latch may have a pull-up transistor that is connected in series with a current source.

Memory elements with leakage compensation

Circuits, methods, and apparatus that prevent easy detection and erasure or modification of an encryption or encoding key. This key may be used to encode and decode a configuration bitstream for an FPGA or other programmable or configurable device. One embodiment of the present invention obfuscates a key then stores it in a memory array on an FPGA. This memory array may be a one-time programmable memory to prevent erasure or modification of the key. After retrieval from storage, a reverse or de-obfuscation is performed to recover the key. Further obfuscation may be achieved by proper layout of the relevant circuitry.

Encryption key obfuscation and storage

A device that is programmable to operate as a memory device, a multiplexer, or a demultiplexer includes: a first column decoder; a memory array coupled to the first column decoder; a plurality of selectors coupled to the memory array; and a second column decoder coupled to the plurality of selectors.

Device programmable to operate as a multiplexer, demultiplexer, or memory device

Growing community of inventors

San Jose, CA, United States of America

David Edward Jefferson