Asymmetric Cryptography in Monero
Author is nowhere close to being a cryptographer. Be sceptical on accuracy.
Before we get to Monero specific stuff, a little bit of context. We are talking asymmetric cryptography here. The “asymmetric” simply means the are two keys:
- the private key (used primarily for signing data and for decrypting data)
- the public key (used primarily for signature verification and encrypting data)
This is in contrast to symmetric cryptography which uses a single key. This key is a secret shared among the parties.
Historically, asymmetric cryptography was based on the problem of factorization of a very large integers back into prime numbers (which is practically impossible for large enough integers).
Recently, asymmetric cryptography is based on a mathematical notion of elliptic curves. Edwards25519 is a specific, well researched and standardized elliptic curve used in Monero.