Zero-knowledge proofs are cryptographic protocols that allow one party (the prover) to prove to another party (the verifier) that they know a value, without revealing any information about the value itself. This concept, first introduced in the 1980s, has evolved significantly, leading to various implementations that enhance privacy and security in digital transactions.

A zero-knowledge proof must satisfy three fundamental properties:
Completeness: If the statement is true, the verifier will be convinced by the prover.
Soundness: If the statement is false, no dishonest prover can convince the verifier that it is true.
Zero-Knowledge: The verifier learns nothing beyond the validity of the statement.