Credit to Greg Maxwell and Pieter Wuille whose various posts ( here, here, and here ) gave us enough of an understanding to implement our own Faketoshi-forger. We encourage you to check these resources out to understand why these continued Satoshi claims are nothing more than frauds.
The following implementation creates a signature (s) from a message hash (H(m)) that will validate against the public key from the genesis block. (Although it can easily be extended for any Satoshi public key). The trick is that the message (m), the pre-image of the message hash, itself cannot be known or derived. Thus this, and the other claims using the construction, is an existensial forgery.
You can browse to https://albacore.io/faketoshi for an generator in js that uses a similar construction.
How to use
git clone firstname.lastname@example.org:albacorelabs/Libra.git stack build stack exec Faketoshi-exe /* Optional */ Post output on twitter claiming to be Satoshi