On 17/10/2019 17:43, jim bell wrote:
Phys.Org: Cryptography without using secret keys. https://phys.org/news/2019-10-cryptography-secret-keys.html
Reminds me of one of the solutions to Reagan's "Trust, but Verify" policy: (supposedly-) unclonable speckle patterns were painted on ICBMs etc, and when they wanted to make sure the ICBMs were where they were supposed to be the inspectors shone light on them and inspected the return patterns. Except the return patterns were secret - the incoming light was secretly chosen by the verifying party, so making forging much harder - a forger would either have to know the incoming light pattern and forge returns from those direction - perhaps possible - or have to forge a token such that it matched to paint from every direction, thought to be impossible. Public speckle patterns weaken that unforgeability. Then there is the elephant-in-the-room problem - this is not a cipher... "An important future application the researchers are now working on is secure transmission of data over a glass fiber." Indeed. Peter Fairbrother