Ed25519

This is a portable implementation of Ed25519. All code is in the public domain.

All code is pure ANSI C without any dependencies, except for the random seed generation which uses standard OS cryptography APIs. If you wish to be entirely portable define ED25519_NO_SEED. This does disable the ed25519_create_seed function however (you can use your own seeding function if you wish.)

Usage

Simply add all .c and .h files in the src/ folder to your project and include ed25519.h in any file you want to use the API. If you prefer to use a shared library, only copy ed25519.h and define ED25519_DLL before importing. A windows DLL is pre-built.

There are no defined types for seeds, signing keys, verifying keys or signatures. Instead simple unsigned char buffers are used with the following sizes:

unsigned char seed[32]
unsigned char signature[64]
unsigned char verify_key[32]
unsigned char signing_key[64]

API

int ed25519_create_seed(unsigned char *seed);

Creates a 32 byte random seed in seed for key generation. seed must be a writable 32 byte buffer.

int ed25519_create_keypair(unsigned char *verify_key, unsigned char *sign_key, const unsigned char *seed);

Creates a new key pair from the given seed. verify_key must be a writable 32 byte buffer, sign_key must be a writable 64 byte buffer and seed must be a 32 byte buffer.

int ed25519_sign(unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *sign_key);
int ed25519_verify(const unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *verify_key);