CHIPMAKER Intel has built a circuit capable of producing a random and unpredictable stream of numbers - picture a monkey on hallucinogenic drugs with a scientific calculator.

Actually, it is a lot more sophisticated than that. Technology Review has donned a white coat, washed its hands and sat down with the chip giant and found out all about its newfound habit of generating randomness.

Generating randomness doesn't just appeal to Monty Python fans, it can also find its place in cryptography, as the ability to spew forth numbers is key in creating, um, encryption keys.

Intel's achievement here is its ability to add the feature to a central processing unit, meaning that it can spew forth random numbers from the guts of something else.

According to Ram Krishnamurthy, an engineer at Intel's Microprocessor Technology Labs, this should speed up encryption processes. For example, as he told Technology Review, when securing data on a hard drive, and add critical extra protection.

According to experts close at hand, anyone can ape a number, but random numbers? Well they are something else.

"If the random numbers are not truly random, for example, if they are biased in some way, then an adversary has a better chance of guessing [or] determining the value," explained mathematician Elaine Barker of the National Institute for Standards and Technology (NIST).

"In the case of cryptographic keys, if the adversary can determine the key without an excessive amount of computing power, then he can breach the confidentiality of that data."

Tucking the encryption into the CPU will also protect against against side channel attacks, according to Krishnamurthy, who added, "There are many ways by which the key can be directly read off of the bus, or attacks that look at how the power supply varies and look for signatures that indicate what the key looks like."

We imagine he is the sort of chap that wears a high-necked cape whenever he visits the cashpoint.

Talk is one thing though, but the nut of this is what is in the chip, and apparently that is a cross-coupled inverter. Technology Review called it a "combination of two basic circuit components that is essentially a memory capable of storing a single 1 or 0."

Unreliability is built into this, and thermal noise is used to add another layer of randomness. With all of this randomness it is likely that the circuit will have an equally unpredictable output.

So far Intel has made a 45nm version, though it expects the fab process to scale lower in time.

Krishnamurthy reckons that the circuit can chuck up 2.4 billion numbers a second, approximately 200 times quicker than any alternative.

So, take away that monkey, and give us back our calculator. µ