FinClip小程序+Rust（三）：一个加密钱包

finclip-rust |---- ios (ios相关代码子目录、xcodeproj子目录，生成项目的iOS Wrapper App） |---- android （Android版的 wrapper app，本文不覆盖。有兴趣的同学自行尝试） |---- desktop （Mac/Linux/Windows版wrapper app，可能是一个Qt或者Electron应用。本文阙如，有时间再继续探讨） |---- mini-app （一个FinClip小程序，主要负责设备端的人机交互） |---- rust （Rust部分的代码，编译构建出来的应该是目标架构下的静态库，输出".a"文件）

mkdir finclip-rust cd flinclip-rust cargo new --lib rust

rust |-- src | |-- lib.rs |-- Cargo.toml

[package] name = "rust-crypto-wallet" version = "0.1.0" edition = "2021" [lib] name = "rustywallet" # this is needed to build for iOS and Android. crate-type = ["staticlib", "lib"] # Android专用，本文不涉及，但留着无害 [target.cfg(target_os = "android").dependencies] jni = { version = "0.19.0", default-features = false } [dependencies] anyhow = "1.0" secp256k1 = { version = "0.20.3", features = ["rand"] } serde = { version = "1.0", features = ["derive"]} serde_json = "1.0" tiny-keccak = { version ="1.4"} web3 = {version = "0.17.0"}

finclip-rust |---- rust |---- Cargo.toml |---- src | |---- lib.rs （我们在这里做FFI的系列繁琐工作，输出C接口） | |---- wallet | |---- mod.rs | |---- wallet_impl.rs |---- examples |---- test.rs

// wallet_impl.rs use anyhow::Result; use secp256k1::{rand::rngs, PublicKey, SecretKey}; use serde::{Deserialize, Serialize}; use tiny_keccak::keccak256; use web3::{ types::{Address}, }; use std::io::BufWriter; use std::{fs::OpenOptions, io::BufReader}; use std::time::{SystemTime, UNIX_EPOCH}; pub fn generate_keypair() -> (SecretKey, PublicKey) { let secp = secp256k1::Secp256k1::new(); let mut rng = rngs::JitterRng::new_with_timer(get_nstime); secp.generate_keypair(&mut rng) } pub fn public_key_address(public_key: &PublicKey) -> Address { let public_key = public_key.serialize_uncompressed(); debug_assert_eq!(public_key[0], 0x04); let hash = keccak256(&public_key[1..]); Address::from_slice(&hash[12..]) } #[derive(Serialize, Deserialize, Debug)] pub struct Wallet { pub secret_key: String, pub public_key: String, pub public_address: String, } impl Wallet { pub fn new(secret_key: &SecretKey, public_key: &PublicKey) -> Self { let addr: Address = public_key_address(&public_key); Wallet { secret_key: format!("{}", secret_key.to_string()), public_key: public_key.to_string(), public_address: format!("{:?}", addr), } } pub fn save_keys(&self, file_path: &str) -> Result<()> { let file = OpenOptions::new() .write(true) .create(true) .open(file_path)?; let buf_writer = BufWriter::new(file); serde_json::to_writer_pretty(buf_writer, self)?; Ok(()) } pub fn retrieve_keys(file_path: &str) -> Result<Wallet> { let file = OpenOptions::new().read(true).open(file_path)?; let buf_reader = BufReader::new(file); let wallet: Wallet = serde_json::from_reader(buf_reader)?; Ok(wallet) } } pub fn get_nstime() -> u64 { let dur = SystemTime::now().duration_since(UNIX_EPOCH).unwrap(); // The correct way to calculate the current time is // `dur.as_secs() * 1_000_000_000 + dur.subsec_nanos() as u64` // But this is faster, and the difference in terms of entropy is // negligible (log2(10^9) == 29.9). dur.as_secs() << 30 | dur.subsec_nanos() as u64 }

// mod.rs: wallet module pub mod wallet_impl;

// lib.rs // // 此部分代码主要负责Rust-C两侧的数据内存结构转换，提供了C侧的函数接口。注意命名规范： // 在C侧使用时，凡是函数名带有 _cwallet的，调用过之后都必须用free_cwallet释放内存， // 否则导致内存泄漏 // use std::ffi::{CStr, CString}; use std::os::raw::c_char; mod wallet; use wallet_impl::Wallet; use crate::wallet::*; #[cfg(target_os = "android")] mod android; #[repr(C)] pub struct CWallet { pub public_key: *mut c_char, pub private_key: *mut c_char, pub public_addr: *mut c_char, } #[no_mangle] pub unsafe extern "C" fn generate_cwallet() -> CWallet { println!("generating wallet"); let (secret_key, pub_key) = wallet_impl::generate_keypair(); // println!("secret key: {}", &secret_key.to_string()); // println!("public key: {}", &pub_key.to_string()); //let pub_address = eth_wallet::public_key_address(&pub_key); //println!("public address: {:?}", pub_address); let rust_wallet = wallet_impl::Wallet::new(&secret_key, &pub_key); println!("rust_wallet: {:?}", &rust_wallet); convert_to_cwallet(rust_wallet) } #[no_mangle] pub unsafe extern "C" fn free_cwallet(cw: CWallet) { drop(CString::from_raw(cw.public_key)); drop(CString::from_raw(cw.private_key)); drop(CString::from_raw(cw.public_addr)); } #[no_mangle] pub unsafe extern "C" fn save_wallet(cw: &CWallet) { let rwallet = convert_to_rwallet(cw); wallet_impl::Wallet::save_keys(&rwallet, "wallet.json").unwrap(); } #[no_mangle] pub unsafe extern "C" fn fetch_cwallet() -> CWallet { match wallet_impl::Wallet::retrieve_keys("wallet.json") { Err(_) => { let wallet = wallet_impl::Wallet { secret_key: "".to_string(), public_key: "".to_string(), public_address: "".to_string(), }; return convert_to_cwallet(wallet) } Ok(w) => return convert_to_cwallet(w) }; } unsafe fn convert_to_cwallet(rwallet: Wallet) -> CWallet { // 转换Rust字符串数据为C的字符串并移交ownership let pubkey = CString::new(rwallet.public_key).unwrap(); let c_pubkey: *mut c_char = pubkey.into_raw(); let seckey = CString::new(rwallet.secret_key).unwrap(); let c_seckey: *mut c_char = seckey.into_raw(); let pubaddr = CString::new(rwallet.public_address).unwrap(); let c_pubaddr: *mut c_char = pubaddr.into_raw(); //println!("crypto wallet address: {}", CStr::from_ptr(c_pubaddr).to_str().unwrap()); let cw = CWallet { public_key: c_pubkey, private_key: c_seckey, public_addr: c_pubaddr, }; //println!("crypto_wallet addr: {}", CStr::from_ptr(cw.public_addr).to_str().unwrap()); cw } unsafe fn convert_to_rwallet(cwallet: &CWallet) -> Wallet { let a = CStr::from_ptr(cwallet.public_addr); let pa = a.to_str().unwrap(); let pk = CStr::from_ptr(cwallet.public_key); let ppk = pk.to_str().unwrap(); let sk = CStr::from_ptr(cwallet.private_key); let psk = sk.to_str().unwrap(); Wallet { secret_key: psk.to_string(), public_key: ppk.to_string(), public_address: pa.to_string(), } }

//test.rs // // 测试在Rust侧生成钱包密钥对，转换成C侧的数据结构。 // 测试钱包在C侧调用接口存储和重新读出钱包密钥 // use std::ffi::{CStr}; //use rustylib::gen::{CWallet}; use rustywallet::{CWallet, generate_cwallet, free_cwallet, save_wallet, fetch_cwallet}; fn main() { unsafe { let wallet: CWallet = generate_cwallet(); println!("---- generated a wallet to be used on C-side ----"); print_wallet(&wallet); println!("---- saving the wallet to wallet.json ----"); save_wallet(&wallet); println!("---- saved! ----"); println!("---- fetching the saved wallet to be exposed to C-side ----"); let fetched = fetch_cwallet(); print_wallet(&fetched); free_cwallet(wallet); // 对应 generate_cwallet() free_cwallet(fetched); // 对应 fetch_wallet() } } unsafe fn print_wallet(wallet: &CWallet) { let a = CStr::from_ptr(wallet.public_addr); let pa = a.to_str().unwrap(); println!("public address=> {}", pa); let pk = CStr::from_ptr(wallet.public_key); let ppk = pk.to_str().unwrap(); println!("public key=> {}", ppk); let sk = CStr::from_ptr(wallet.private_key); let psk = sk.to_str().unwrap(); println!("private key=> {}", psk); }

cargo run --example test

Compiling rust-crypto-wallet v0.1.0 (/Users/cliang/rusty/finclip-rust/rust-wallet) Finished dev [unoptimized + debuginfo] target(s) in 14.82s Running `target/debug/examples/test` generating wallet rust_wallet: Wallet { secret_key: "0cb5fe0b77a75a43c5d5aac449df17c1849ef39da6134419c7416ef79304e5bb", public_key: "03b03e2bde039d222cb8b9bc36d9919323485ae495916d8c234c6910c75ad4e1c5", public_address: "0x1a2c83981ab4679d10b7889f9f97028265991c8f" } ---- generated a wallet to be used on C-side ---- public address=> 0x1a2c83981ab4679d10b7889f9f97028265991c8f public key=> 03b03e2bde039d222cb8b9bc36d9919323485ae495916d8c234c6910c75ad4e1c5 private key=> 0cb5fe0b77a75a43c5d5aac449df17c1849ef39da6134419c7416ef79304e5bb ---- saving the wallet to wallet.json ---- ---- saved! ---- ---- fetching the saved wallet to be exposed to C-side ---- public address=> 0x1a2c83981ab4679d10b7889f9f97028265991c8f public key=> 03b03e2bde039d222cb8b9bc36d9919323485ae495916d8c234c6910c75ad4e1c5 private key=> 0cb5fe0b77a75a43c5d5aac449df17c1849ef39da6134419c7416ef79304e5bb

cargo lipo --release

cbindgen src/lib.rs -l c > rustywallet.h