A simulation of interactive and non-interactive zero knowledge proof protocols (Schnorr's Protocol and Flat-Shamir heuristic) for password authentication.

• Interactive and Non-interactive ZKP modes
• Rejection of invalid/tampered proofs
• Domain separation in hashing (zkp|) to avoid collisions
• Reads from /dev/urandom for secure randomness

Clone the repository and build the project.

git clone https://github.com/xshthkr/nolook.git
cd nolook
make

The binary will be in the bin directory.

./bin/nolook

1. Commitment: Alice picks random r, sends t = g^r mod p to Bob
2. Challenge: Bob replies with random c
3. Response: Alice computes s = (r - c·x) mod q and sends it
4. Verification: Bob checks g^s ?= t·y^c mod p

There is no Bob interacting with Alice. Challenge c is derived via:

  c = Hash("zkp|" + g "|" + y + "|" + t) % q;

The rest of the protocl remains the same.

• Linux (uses /dev/urandom)
• OpenSSL (libssl-dev or openssl headers) for SHA256
• C99 or later
• 64-bit system (uses uint64_t)

• Schnorr's Original Paper: Efficient Signature Generation by Smart Cards
• Secure Remote Password protocol: Stanford