Cryptography

A digital certificate, specifically an X.509 digital certificate, is a standardized electronic document that binds a public key to an identity. It's like a digital ID card, issued and signed by a trusted third party, the Certificate Authority (CA), to verify the authenticity of a public key.

From a high level perspective this is how BLS (also known as Boneh–Lynn–Shacham) signature scheme works.

In simple terms, hash functions transform input data of arbitrary size (e.g. text, binary, etc) to fixed-length output (called hash value, hash code, fingerprint, message digest or simply hash) in a deterministic way. What else?

A cryptographic commitment scheme is a way of committing to a statement without revealing the statement itself or reveal it at a later time.

The easiest way to understand Elliptic Curve (EC), point addition, scalar multiplication and trapdoor function; explained with simple graphs and animations.

Zero-knowledge is a method to prove that you know a secret ``x`` (e.g. a password, private key, piece of knowledge, etc) without revealing that secret.

— layout: post title: "Zero-knowledge proofs" subtitle: Cryptography date: 2019-08-26 tags: ["cryptography", "zero-knowledge-proof", "math", "python", "zcash"] —

Schnorr is another digital signature scheme known for its simplicity, no division, no inversion, just plain old multiplication. Here is my simple 16 lines implementation in Python.

Elliptic curve cryptography (ECC) and digital signature algorithm (ECDSA) are more complex than RSA or ElGamal but I will try my best to hide the hairy math and the implementation details.