A Brief History of Cryptography in Blockchain
This timeline walks through the cryptographic milestones that made modern blockchains possible — from early digital signatures to privacy-preserving zero-knowledge systems.
1970s–1980s: The Foundations
- 1976: Diffie–Hellman key exchange — the first public-key system.
- 1978: RSA — the first practical digital signature system (not used in blockchain).
- 1985: ElGamal signatures — the basis for DSA and later ECDSA.
These inventions made secure communication without shared secrets possible.
1990s: Hash Functions & Merkle Trees
- 1992: Merkle Trees proposed for efficient data verification.
- 1995: SHA-1 becomes a widely used hash function.
Hashing and Merkle structures became critical for securely linking data together — perfect for a blockchain.
Try the Merkle Tree Explorer →2008–2009: Bitcoin and ECDSA
- 2008: Satoshi Nakamoto publishes the Bitcoin whitepaper.
- 2009: The first block is mined using ECDSA signatures and SHA-256 hashing.
Bitcoin uses ECDSA on the secp256k1 curve to sign transactions. This is still standard for many coins.
Try the ECDSA Playground →2015: Ethereum and Smart Contracts
- Ethereum reuses ECDSA and Keccak-256 for its core cryptography.
- Smart contracts enable new use cases for cryptography: commitments, proofs, identity.
Ethereum expands the cryptographic surface dramatically — and sparks the ZK revolution.
2017–2020: The Zero-Knowledge Era
- Zcash: Introduces zk-SNARKs for private transactions.
- StarkWare / zkSync: Scale Ethereum with zero-knowledge rollups.
- zk-SNARK, zk-STARK, Bulletproofs, Halo 2: Different proving systems emerge.
Try the ZK Proof Playground →2020–Today: Aggregation, MPC & Threshold Signatures
- BLS Signatures: Used in Ethereum 2.0 for validator aggregation.
- FROST: Fast threshold signing with EdDSA/Schnorr (1–2 rounds).
- MPC Wallets: Fireblocks, ZenGo, and others use threshold cryptography in production.
What’s Next?
Next-generation cryptography is being integrated into wallets, rollups, and chains. Keep an eye on:
- ERC-4337 session keys
- FROST for multisig wallets
- zkVMs and recursive proofs