feat: add simple contract

__crypto/simple_contract/src/main.rs

@@ -0,0 +1,31 @@
+pub mod util;
+pub mod tx;
+pub mod credit;
+
+use std::str::FromStr;
+use secp256k1::{Message, Secp256k1, Signature};
+use util::*;
+
+fn main() -> XResult<()> {
+    let (pri_key, pub_key) = make_key_pair();
+    println!("{:?}", pri_key);
+    println!("{:?}", pub_key);
+    println!("{:?}", JsonKeyPair::from(pri_key, pub_key).to_json());
+    println!("{:?}", JsonKeyPair::from(pri_key, pub_key).to_key_pair());
+    println!("{}", make_btc_address(&pub_key));
+
+    let p256k1 = Secp256k1::new();
+    let s =calc_sha256("hello".as_bytes());
+    let message = Message::from_slice(&s)?;
+
+    let sign = p256k1.sign(&message, &pri_key);
+    let sign_hex = format!("{}", sign);
+    println!("{}", sign_hex);
+
+    let sig = Signature::from_str(&sign_hex)?;
+
+    let result  = p256k1.verify(&message, &sig, &pub_key);
+    println!("{:?}", result);
+
+    Ok(())
+}