Crate ed25519_dalek
source ·Expand description
A Rust implementation of ed25519 key generation, signing, and verification.
Example
Creating an ed25519 signature on a message is simple.
First, we need to generate a Keypair
, which includes both public and
secret halves of an asymmetric key. To do so, we need a cryptographically
secure pseudorandom number generator (CSPRNG). For this example, we’ll use
the operating system’s builtin PRNG:
extern crate rand;
extern crate ed25519_dalek;
use rand::rngs::OsRng;
use ed25519_dalek::Keypair;
use ed25519_dalek::Signature;
let mut csprng = OsRng{};
let keypair: Keypair = Keypair::generate(&mut csprng);
We can now use this keypair
to sign a message:
use ed25519_dalek::{Signature, Signer};
let message: &[u8] = b"This is a test of the tsunami alert system.";
let signature: Signature = keypair.sign(message);
As well as to verify that this is, indeed, a valid signature on
that message
:
use ed25519_dalek::Verifier;
assert!(keypair.verify(message, &signature).is_ok());
Anyone else, given the public
half of the keypair
can also easily
verify this signature:
use ed25519_dalek::{PublicKey, Verifier};
let public_key: PublicKey = keypair.public;
assert!(public_key.verify(message, &signature).is_ok());
Serialisation
PublicKey
s, SecretKey
s, Keypair
s, and Signature
s can be serialised
into byte-arrays by calling .to_bytes()
. It’s perfectly acceptible and
safe to transfer and/or store those bytes. (Of course, never transfer your
secret key to anyone else, since they will only need the public key to
verify your signatures!)
use ed25519_dalek::{PUBLIC_KEY_LENGTH, SECRET_KEY_LENGTH, KEYPAIR_LENGTH, SIGNATURE_LENGTH};
let public_key_bytes: [u8; PUBLIC_KEY_LENGTH] = public_key.to_bytes();
let secret_key_bytes: [u8; SECRET_KEY_LENGTH] = keypair.secret.to_bytes();
let keypair_bytes: [u8; KEYPAIR_LENGTH] = keypair.to_bytes();
let signature_bytes: [u8; SIGNATURE_LENGTH] = signature.to_bytes();
And similarly, decoded from bytes with ::from_bytes()
:
let public_key: PublicKey = PublicKey::from_bytes(&public_key_bytes)?;
let secret_key: SecretKey = SecretKey::from_bytes(&secret_key_bytes)?;
let keypair: Keypair = Keypair::from_bytes(&keypair_bytes)?;
let signature: Signature = Signature::try_from(&signature_bytes[..])?;
Using Serde
If you prefer the bytes to be wrapped in another serialisation format, all
types additionally come with built-in serde support by
building ed25519-dalek
via:
$ cargo build --features="serde"
They can be then serialised into any of the wire formats which serde supports. For example, using bincode:
use bincode::serialize;
let encoded_public_key: Vec<u8> = serialize(&public_key).unwrap();
let encoded_signature: Vec<u8> = serialize(&signature).unwrap();
After sending the encoded_public_key
and encoded_signature
, the
recipient may deserialise them and verify:
use bincode::deserialize;
let message: &[u8] = b"This is a test of the tsunami alert system.";
let decoded_public_key: PublicKey = deserialize(&encoded_public_key).unwrap();
let decoded_signature: Signature = deserialize(&encoded_signature).unwrap();
let verified: bool = decoded_public_key.verify(&message, &decoded_signature).is_ok();
assert!(verified);
Re-exports
pub extern crate ed25519;
Structs
- An “expanded” secret key.
- An ed25519 keypair.
- An ed25519 public key.
- An EdDSA secret key.
- The SHA-512 hash algorithm with the SHA-512 initial hash value.
- Ed25519 signature.
Constants
- The length of an “expanded” ed25519 key,
ExpandedSecretKey
, in bytes. - The length of an ed25519
Keypair
, in bytes. - The length of an ed25519
PublicKey
, in bytes. - The length of a ed25519
SecretKey
, in bytes. - The length of a ed25519
Signature
, in bytes.
Traits
- The
Digest
trait specifies an interface common for digest functions. - Sign the provided message bytestring using
Self
(e.g. a cryptographic key or connection to an HSM), returning a digital signature. - Verify the provided message bytestring using
Self
(e.g. a public key)
Type Definitions
- Errors which may occur while processing signatures and keypairs.