While the need for quantum-computing proof cryptography increases, I propose a new (?) digital signature algorithm. Although I find it hard to imagine that I'm the first to come up with this idea, I've not read about it, nor have I seen it being used. However, I'm not a cryptographer, so I may have missed or be overlooking things. Please let me know if this algorithm was already proposed by others. Also, if anyone believes that this algorithm should /not/ be used, or restrictions should apply to its application, please let me know the reasons why. Basis - The privkey (private key) and pubkey (public key) are mathematically independent cryptographically secure random numbers, long enough to (hopefully) be globally unique. - Only cryptographically secure hash functions (HMACs) are to be used (collissions must be practically impossible to find). Simplified algorithm Not taking into account possible length extension attacks: Sign: step 1: sig0 := hash(privkey + text) step 2: sig1 := ...