improvement: event signature validation is 100x faster

Switched to latest (git) release of secp256k1, which has more
efficient verification-only context for Schnorr.  Switched to single
pre-instantiated instance of the verifier.

Cargo.lock

@@ -66,6 +66,12 @@ dependencies = [
  "serde 1.0.131",
 ]
 
+[[package]]
+name = "bitcoin_hashes"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "006cc91e1a1d99819bc5b8214be3555c1f0611b169f527a1fdc54ed1f2b745b0"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -645,7 +651,7 @@ checksum = "38bf9645c8b145698bb0b18a4637dcacbc421ea49bef2317e4fd8065a387cf21"
 name = "nostr-rs-relay"
 version = "0.2.2"
 dependencies = [
- "bitcoin_hashes",
+ "bitcoin_hashes 0.9.7",
  "config",
  "env_logger",
  "futures",
@@ -1031,10 +1037,9 @@ checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 [[package]]
 name = "secp256k1"
 version = "0.20.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97d03ceae636d0fed5bae6a7f4f664354c5f4fcedf6eef053fef17e49f837d0a"
+source = "git+https://github.com/rust-bitcoin/rust-secp256k1.git?rev=50034ccb18fdd84904ab3aa6c84a12fcced33209#50034ccb18fdd84904ab3aa6c84a12fcced33209"
 dependencies = [
- "bitcoin_hashes",
+ "bitcoin_hashes 0.10.0",
  "rand 0.6.5",
  "secp256k1-sys",
  "serde 1.0.131",
@@ -1043,8 +1048,7 @@ dependencies = [
 [[package]]
 name = "secp256k1-sys"
 version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "827cb7cce42533829c792fc51b82fbf18b125b45a702ef2c8be77fce65463a7b"
+source = "git+https://github.com/rust-bitcoin/rust-secp256k1.git?rev=50034ccb18fdd84904ab3aa6c84a12fcced33209#50034ccb18fdd84904ab3aa6c84a12fcced33209"
 dependencies = [
  "cc",
 ]

Cargo.toml

@@ -15,7 +15,7 @@ thiserror = "^1"
 uuid = { version = "^0.8", features = ["v4"] }
 config = { version = "0.11", features = ["toml"] }
 bitcoin_hashes = { version = "^0.9", features = ["serde"] }
-secp256k1 = { version = "^0.20", features = ["rand", "rand-std", "serde", "bitcoin_hashes"] }
+secp256k1 = {git = "https://github.com/rust-bitcoin/rust-secp256k1.git", rev = "50034ccb18fdd84904ab3aa6c84a12fcced33209", features = ["rand", "rand-std", "serde", "bitcoin_hashes"] }
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = "^1.0"
 hex = "^0.4"

src/event.rs

@@ -3,14 +3,19 @@ use crate::config;
 use crate::error::Error::*;
 use crate::error::Result;
 use bitcoin_hashes::{sha256, Hash};
+use lazy_static::lazy_static;
 use log::*;
-use secp256k1::{schnorrsig, Secp256k1};
+use secp256k1::{schnorr, Secp256k1, VerifyOnly, XOnlyPublicKey};
 use serde::{Deserialize, Deserializer, Serialize};
 use serde_json::value::Value;
 use serde_json::Number;
 use std::str::FromStr;
 use std::time::SystemTime;
 
+lazy_static! {
+    pub static ref SECP: Secp256k1<VerifyOnly> = Secp256k1::verification_only();
+}
+
 /// Event command in network format
 #[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
 pub struct EventCmd {
@@ -109,12 +114,15 @@ impl Event {
             return false;
         }
         // * validate the message digest (sig) using the pubkey & computed sha256 message hash.
-        let secp = Secp256k1::new();
-        let sig = schnorrsig::Signature::from_str(&self.sig).unwrap();
-        let message = secp256k1::Message::from(digest);
-        let pubkey = schnorrsig::PublicKey::from_str(&self.pubkey).unwrap();
-        let verify = secp.schnorrsig_verify(&sig, &message, &pubkey);
-        matches!(verify, Ok(()))
+        let sig = schnorr::Signature::from_str(&self.sig).unwrap();
+        if let Ok(msg) = secp256k1::Message::from_slice(digest.as_ref()) {
+            let pubkey = XOnlyPublicKey::from_str(&self.pubkey).unwrap();
+            let verify = SECP.verify_schnorr(&sig, &msg, &pubkey);
+            matches!(verify, Ok(()))
+        } else {
+            warn!("Error converting digest to secp256k1 message");
+            false
+        }
     }
 
     /// Convert event to canonical representation for signing.

src/main.rs

@@ -98,9 +98,9 @@ async fn handle_web_request(
         }
         ("/", false) => {
             // handle request at root with no upgrade header
-            Ok(Response::new(Body::from(format!(
-                "This is a Nostr relay.\n"
-            ))))
+            Ok(Response::new(Body::from(
+                "This is a Nostr relay.\n".to_string(),
+            )))
         }
         (_, _) => {
             //handle any other url