Asymmetric Cryptography in Monero¶

Before we get to Monero specific stuff, a little bit of context. We are talking asymmetric cryptography here. The "asymmetric" simply means there 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 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.