On-chip randomness generation

Abstract

An on-chip true noise generator including an embedded noise source with a low-voltage, high-noise zener diode(s), and an in-situ close-loop zener diode power control circuit. The present invention proposes the use of heavily doped polysilicon and silicon p-n diode(s) structures to minimize the breakdown voltage, increasing noise level and improving reliability. The present invention also proposes an in-situ close-loop zener diode control circuit to safe-guard the zener diode from catastrophic burn-out.

Description

FIELD OF THE INVENTION[0001]The present invention relates to random number generation. More specifically, the present invention relates to generating random noise / numbers embedded in a semiconductor chip with a reduced operating voltage.BACKGROUND[0002]Good cryptography requires good random numbers. Almost all cryptographic protocols require the generation and use of secret values that must be unknown to attackers. For example, random number generators are required to generate public / private key pairs for asymmetric (public key) algorithms including RSA, DSA, and Diffie-Hellman. Keys for symmetric and hybrid cryptosystems are also generated randomly. RNGs are also used to create challenges, nonces (salts), padding bytes, and blinding values. The one time pad—the only provably-secure encryption system—uses as much key material as cipher text and requires that the keystream be generated from a truly random process.[0003]Generating real random numbers has become increasingly vital to i...

AI Technical Summary

Benefits of technology

The present invention is a noise generator that can be embedded into other circuitry. It includes a highly doped diode and an automatic avalanche current control loop to optimize between performance and reliability. The generator can amplify the noise level using multiple stages of differential amplification, while also neutralizing the effects of common causes of variability. The invention also includes an algorithm for automatic voltage regulation and a methodology for conducting supply voltage regulation for automatic avalanche current control. Additionally, there is a stochastic noise amplification apparatus with paired noise generating sources to amplify the noise level and neutralize the effects of common causes of variability.

Problems solved by technology

However, traditional pseudo-random numbers generated by digital circuits no longer meet the security requirements due to the increasing availability of powerful deciphering computing systems.

However, at least two challenges must be overcome for the noise source to be implemented in the integrated circuits.

Second, when the diode is operated in the avalanche mode close to the breakdown condition, the current-voltage curve is very steep.

If the voltage is too high, the current becomes very large and the diode could be damaged by breakdown.

Although the immediate solution for the discrete zener diode is to enlarge the diode size, it is not feasible in integrated circuits because of the parasitic capacitance concern that will deteriorate circuit performance, cost considerations and reliability concerns.

As zener diodes are p-n junction diodes, increasing p-n junction doping level and abruptness will theoretically result in lower breakdown voltages.

However, they use amplifier circuits in each noise generating block which will distort the noise spectrum because of the limited bandwidth of the amplifiers.

The main drawback of this approach is that the required gain level of amplification is very high (several orders of magnitude) and the resulting reduction in the bandwidth of the amplifier (note that because the product of the gain and the bandwidth of an amplifier is about constant).

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