Which cryptographic algorithm is used to generate the secret and public keys?

Question

The Stellar keypair is generated easily from various SDKs, but which algorithm do the SDKs use?

Answer 1

Stellar is using Ed25519 public-key signature system.

After generating a new key pair (public and private key), both keys are strkey-encoded. strkey works like this:

1. Prepend keys with a version byte:
   • public key with 6 << 3 byte (decimal: 48, this later encodes to letter G),
   • private key with 18 << 3 byte (decimal: 144, this later encodes to letter S).
2. Calculate checksum of public or private key prepended with version byte using CRC16-XModem.
3. Use base32 encoding to encode version byte, public/private key and checksum. The final string should consists of 56 characters.

Code:

• Javascript
• Go
• Java