enr ============ [![Build Status]][Build Link] [![Doc Status]][Doc Link] [![Crates Status]][Crates Link] [Build Status]: https://github.com/AgeManning/enr/workflows/build/badge.svg?branch=master [Build Link]: https://github.com/AgeManning/enr/actions [Doc Status]: https://docs.rs/enr/badge.svg [Doc Link]: https://docs.rs/enr [Crates Status]: https://img.shields.io/crates/v/enr.svg [Crates Link]: https://crates.io/crates/enr [Documentation at docs.rs](https://docs.rs/enr) This crate contains an implementation of an Ethereum Node Record (ENR) as specified by [EIP-778](https://eips.ethereum.org/EIPS/eip-778) extended to allow for the use of ed25519 keys. An ENR is a signed, key-value record which has an associated `NodeId` (a 32-byte identifier). Updating/modifying an ENR requires an `EnrKey` in order to re-sign the record with the associated key-pair. ENR's are identified by their sequence number. When updating an ENR, the sequence number is increased. Different identity schemes can be used to define the node id and signatures. Currently only the "v4" identity is supported and is set by default. ## Signing Algorithms User's wishing to implement their own singing algorithms simply need to implement the `EnrKey` trait and apply it to an `Enr`. By default, `k256::SigningKey` implement `EnrKey` and can be used to sign and verify ENR records. This library also implements `EnrKey` for `ed25519_dalek::Keypair` via the `ed25519` feature flag. Furthermore, a `CombinedKey` is provided if the `ed25519` feature flag is set, which provides an ENR type that can support both `secp256k1` and `ed25519` signed ENR records. Examples of the use of each of these key types is given below. ## Features This crate supports a number of features. - `serde`: Allows for serde serialization and deserialization for ENRs. - `ed25519`: Provides support for `ed25519_dalek` keypair types. - `rust-secp256k1`: Uses `c-secp256k1` for secp256k1 keys. These can be enabled via adding the feature flag in your `Cargo.toml` ```toml enr = { version = "*", features = ["serde", "ed25519", "rust-secp256k1"] } ``` ## Examples To build an ENR, an `EnrBuilder` is provided. #### Building an ENR with the default `k256` key type ```rust use enr::{EnrBuilder, k256}; use std::net::Ipv4Addr; use rand::thread_rng; // generate a random secp256k1 key let mut rng = thread_rng(); let key = k256::ecdsa::SigningKey::random(&mut rng); let ip = Ipv4Addr::new(192,168,0,1); let enr = EnrBuilder::new("v4").ip4(ip).tcp4(8000).build(&key).unwrap(); assert_eq!(enr.ip4(), Some("192.168.0.1".parse().unwrap())); assert_eq!(enr.id(), Some("v4".into())); ``` #### Building an ENR with the `CombinedKey` type (support for multiple signing algorithms). Note the `ed25519` feature flag must be set. This makes use of the `EnrBuilder` struct. ```rust use enr::{EnrBuilder, CombinedKey}; use std::net::Ipv4Addr; // create a new secp256k1 key let key = CombinedKey::generate_secp256k1(); // or create a new ed25519 key let key = CombinedKey::generate_ed25519(); let ip = Ipv4Addr::new(192,168,0,1); let enr = EnrBuilder::new("v4").ip4(ip).tcp4(8000).build(&key).unwrap(); assert_eq!(enr.ip4(), Some("192.168.0.1".parse().unwrap())); assert_eq!(enr.id(), Some("v4".into())); ``` #### Modifying an ENR ENR fields can be added and modified using the getters/setters on `Enr`. A custom field can be added using `insert` and retrieved with `get`. ```rust use enr::{EnrBuilder, k256::ecdsa::SigningKey, Enr}; use std::net::Ipv4Addr; use rand::thread_rng; // specify the type of ENR type DefaultEnr = Enr; // generate a random secp256k1 key let mut rng = thread_rng(); let key = SigningKey::random(&mut rng); let ip = Ipv4Addr::new(192,168,0,1); let mut enr = EnrBuilder::new("v4").ip4(ip).tcp4(8000).build(&key).unwrap(); enr.set_tcp4(8001, &key); // set a custom key enr.insert("custom_key", &vec![0,0,1], &key); // encode to base64 let base_64_string = enr.to_base64(); // decode from base64 let decoded_enr: DefaultEnr = base_64_string.parse().unwrap(); assert_eq!(decoded_enr.ip4(), Some("192.168.0.1".parse().unwrap())); assert_eq!(decoded_enr.id(), Some("v4".into())); assert_eq!(decoded_enr.tcp4(), Some(8001)); assert_eq!(decoded_enr.get("custom_key"), Some(vec![0,0,1].as_slice())); ``` #### Encoding/Decoding ENR's of various key types ```rust use enr::{EnrBuilder, k256::ecdsa::SigningKey, Enr, ed25519_dalek::Keypair, CombinedKey}; use std::net::Ipv4Addr; use rand::thread_rng; use rand::Rng; // generate a random secp256k1 key let mut rng = thread_rng(); let key = SigningKey::random(&mut rng); let ip = Ipv4Addr::new(192,168,0,1); let enr_secp256k1 = EnrBuilder::new("v4").ip4(ip).tcp4(8000).build(&key).unwrap(); // encode to base64 let base64_string_secp256k1 = enr_secp256k1.to_base64(); // generate a random ed25519 key let mut rng = rand_07::thread_rng(); let key = Keypair::generate(&mut rng); let enr_ed25519 = EnrBuilder::new("v4").ip4(ip).tcp4(8000).build(&key).unwrap(); // encode to base64 let base64_string_ed25519 = enr_ed25519.to_base64(); // decode base64 strings of varying key types // decode the secp256k1 with default Enr let decoded_enr_secp256k1: Enr = base64_string_secp256k1.parse().unwrap(); // decode ed25519 ENRs let decoded_enr_ed25519: Enr = base64_string_ed25519.parse().unwrap(); // use the combined key to be able to decode either let decoded_enr: Enr = base64_string_secp256k1.parse().unwrap(); let decoded_enr: Enr = base64_string_ed25519.parse().unwrap(); ```