# Module BSV::Primitives::Schnorr <a id="module-BSV-Primitives-Schnorr"></a>

BRC-94 Schnorr zero-knowledge proof protocol.

Provides generation and verification of Schnorr proofs for verifiable
revelation of ECDH shared secrets. Given two public keys A and B and a shared
secret S = a*B (where a is A's private key), the prover can demonstrate
knowledge of the discrete log relationship without revealing the private key.

- **@see** `https://github.com/bitcoin-sv/BRCs/blob/master/peer-to-peer/0094.md` BRC-94

## Public Class Methods
### `generate_proof(private_key, public_key_a, public_key_b, shared_secret)` <a id="method-c-generate_proof"></a> <a id="generate_proof-class_method"></a>
Generate a Schnorr proof of knowledge of a shared secret.

Proves that the prover knows the private key `a` such that +shared_secret = a
* public_key_b+, without revealing `a`.
- **@param** `private_key` [PrivateKey] the prover's private key (a)
- **@param** `public_key_a` [PublicKey] the prover's public key (A = a*G)
- **@param** `public_key_b` [PublicKey] the counterparty's public key (B)
- **@param** `shared_secret` [PublicKey] the ECDH shared secret (S = a*B)
- **@return** [Proof] the Schnorr proof

### `verify_proof(public_key_a, public_key_b, shared_secret, proof)` <a id="method-c-verify_proof"></a> <a id="verify_proof-class_method"></a>
Verify a Schnorr proof of knowledge of a shared secret.

Checks the two verification equations:
1.  z*G == R + e*A
2.  z*B == S' + e*S
- **@param** `public_key_a` [PublicKey] the prover's public key
- **@param** `public_key_b` [PublicKey] the counterparty's public key
- **@param** `shared_secret` [PublicKey] the claimed shared secret
- **@param** `proof` [Proof] the Schnorr proof to verify
- **@return** [Boolean] +true+ if the proof is valid