Use free running oscillators as a source of phase noise to generate randomness.
Output of a fast oscillator is sampled on the rising edge of a slower clock using D flip-flop.
Oscillator jitter causes randomness in exact sampled values.
> More Precisely: 1 t(n + 1) < m[C 0 + C 1 r(n) + C 2 r 2 (n)] B(n) = 0 otherwise Where, .t(n+1) = ( (t(n) + T s )MOD(C 0 + C 1 r(n) + C 2 r 2 (n)) .m = fast oscillator duty cycle. [0, 1] .C 0 , C 1 , C 2 = Model non-linear transfer function .T s = slow clock frequency .MOD = modulo operator B(n) t(n+1) r(n) Paper: Craig S. Petrie, and J. Alvin Connelly , “A Noise-Based IC Random Number Generator for Applications in Cryptography”
Uses discrete-time analog signal processing techniques such as PWL system
Divergence of dynamic properties of the signal (or trajectory) and addition of noise generates randomness.
> More Precisely: 1 i(n+1) < I ref B(n) = 0 otherwise Where, .i(n+1) = A 1 [[B N (i(n) + r(n))] MOD I ref ] + A 0 .N = # of stages .B = Stage gain .I ref = Reference current .A 0 and A 1 = Sample-Hold offset and gain Paper: Craig S. Petrie, and J. Alvin Connelly , “A Noise-Based IC Random Number Generator for Applications in Cryptography”
Charles W. O’Donnell, G. Edward Suh, and Srinivas Devadas, “PUF Based Random Number Generation”, MIT CSAIL, Technical Memo, 2004
Karsten Nohl, “Implementable Privacy for RFID Systems”, Ph.D Thesis, University of Virginia, 2009
Damith C. Ranasinghe, “Lightweight Cryptography on Low cost RFID”, Networked RFID Systems and Lightweight Cryptography, Springer, 2007
Wenyi Che, Huan Deng, Xi Tan, and Junyu Wang, “A Random Number Generator for Application in RFID Tags”, Networked RFID Systems and Lightweight Cryptography, Springer, 2007
Craig S. Petrie, M and J. Alvin Connelly, “A Noise-Based IC Random Number Generator for Applications in Cryptography”, IEEE Transactions on Circuits and Systems: Fundamental Theory, Vol. 47, No. 5, May 2000
Ganesh K. Balachandran, and Raymond E. Barnett, “A 440-nA True Random Number Generator for Passive RFID Tags”, IEEE Transactions on Circuit and Systems, Vol. 55. No. 11, December 2008
Daniel E. Holcomb, Wayne P. Burleson, and Kevin Fu, “Initial SRAM State as a Fingerprint and Source of True Random Numbers for RFID Tags”, RFIDSec, 2007