Stuff with Signatures

Digital signatures allow us to verify that a piece of data has been unmodified and was produced by a certain entity. They are especially useful in the context of zero-knowledge proofs, where they enable a party with access to the signature and its underlying data to prove properties about the data without revealing the data itself.

To aid the development of zero-knowledge applications and the adoption of digital signatures as a whole, here is a list of types of data in the world that come with digital signatures, along with projects that generate zero-knowledge proofs about them.

Want to contribute? Submit a pull request!

The List

• Email (DKIM signatures)
  • [PROJECT] ZK Email
  • [PROJECT] ZKP2P
• Passports (150+ countries have biometric/e-passports)
  • [PROJECT] Proof of Passport
• EU Residence Cards for foreign nationals
• eIDAS (future electronic id cards for EU citizens)
• Credit Card Transactions (EMV cryptograms)
  • [PROJECT] GOAT RAMP
• HTTPS/TLS (signatures are only used during the key-exchange handshake, to prove authenticity of sessions a workaround is needed)
  • [PROJECT] TLS Notary (Performs an MPC with a 3rd party notary)
  • [PROJECT] Reclaim Protocol (A 3rd party provides an attesting signature)
• Git commits
• Ethereum Attestation Service (EAS), including Coinbase onchain verification and Gitcoin Passport
• Proof of Humanity
• PDFs (some PDFs e.g. Docusign are digitally signed by certificate authorities)
  • [PROJECT] zkCert

National ID Cards

• India's Aadhaar
  • [PROJECT] Anon aadhaar
• Japan's My Number Cards
  • [PROJECT] Myna Wallet
• Taiwan DID
  • [PROJECT] tw-did

Onchain data

• Ethereum transactions and state
  • [PROJECT] Axiom
• Poaps
• Semaphore identities