Use FNV-1a hash instead of SHA2 for relay ID generation

Cargo.lock

@@ -104,7 +104,6 @@ dependencies = [
  "scraper",
  "serde",
  "serde_json",
- "sha2",
  "signal-hook",
  "tempfile",
  "termion",

Cargo.toml

@@ -42,7 +42,6 @@ rgb = "0.8.37"
 url = "2.5.0"
 tokio-tungstenite = { version = "0.26.2", features = ["rustls-tls-native-roots"] }
 rustls = { version = "0.23.26", default-features = false, features = ["aws_lc_rs"] }
-sha2 = "0.10.8"
 tokio-util = "0.7.10"
 
 [build-dependencies]

src/cmd/session.rs

@@ -22,6 +22,7 @@ use crate::config::{self, Config};
 use crate::encoder::{AsciicastV2Encoder, AsciicastV3Encoder, RawEncoder, TextEncoder};
 use crate::file_writer::{FileWriterStarter, Metadata};
 use crate::forwarder;
+use crate::hash;
 use crate::locale;
 use crate::notifier::{self, Notifier, NullNotifier};
 use crate::pty;
@@ -30,7 +31,6 @@ use crate::session::{self, KeyBindings, SessionStarter};
 use crate::status;
 use crate::stream::Stream;
 use crate::tty::{DevTty, FixedSizeTty, NullTty, Tty};
-use crate::util;
 
 impl cli::Session {
     pub fn run(mut self, config: &Config) -> Result<()> {
@@ -375,7 +375,7 @@ struct Relay {
 
 impl Relay {
     fn id(&self) -> String {
-        util::sha2_digest(self.ws_producer_url.as_ref())
+        format!("{:x}", hash::fnv1a_128(self.ws_producer_url.as_ref()))
     }
 }
 

src/hash.rs

@@ -0,0 +1,36 @@
+// This module implements FNV-1a hashing algorithm
+// http://www.isthe.com/chongo/tech/comp/fnv/
+
+const FNV_128_PRIME: u128 = 309485009821345068724781371; // 2^88 + 2^8 + 0x3b
+const FNV_128_OFFSET_BASIS: u128 = 144066263297769815596495629667062367629;
+
+pub fn fnv1a_128<D: AsRef<[u8]>>(data: D) -> u128 {
+    let mut hash = FNV_128_OFFSET_BASIS;
+
+    for byte in data.as_ref() {
+        hash ^= *byte as u128;
+        hash = hash.wrapping_mul(FNV_128_PRIME);
+    }
+
+    hash
+}
+
+#[cfg(test)]
+mod tests {
+    use super::fnv1a_128;
+
+    #[test]
+    fn digest() {
+        assert_eq!(
+            fnv1a_128("Hello World!"),
+            0xd2d42892ede872031d2593366229c2d2
+        );
+
+        assert_eq!(
+            fnv1a_128("Hello world!"),
+            0x3c94fff9ede872031d95566a45770eb2
+        );
+
+        assert_eq!(fnv1a_128("🦄🌈"), 0xa25841ae4659905b36cb0d359fad39f);
+    }
+}

src/main.rs

@@ -7,6 +7,7 @@ mod config;
 mod encoder;
 mod file_writer;
 mod forwarder;
+mod hash;
 mod io;
 mod leb128;
 mod locale;

src/util.rs

@@ -1,10 +1,8 @@
-use std::fmt::Write;
 use std::path::{Path, PathBuf};
 use std::{io, thread};
 
 use anyhow::{anyhow, bail, Result};
 use reqwest::Url;
-use sha2::Digest;
 use tempfile::NamedTempFile;
 
 pub fn get_local_path(filename: &str) -> Result<Box<dyn AsRef<Path>>> {
@@ -118,20 +116,6 @@ impl Utf8Decoder {
     }
 }
 
-pub fn sha2_digest(s: &str) -> String {
-    let mut hasher = sha2::Sha224::new();
-    hasher.update(s.as_bytes());
-
-    hasher
-        .finalize()
-        .as_slice()
-        .iter()
-        .fold(String::new(), |mut out, byte| {
-            let _ = write!(out, "{byte:02X}");
-            out
-        })
-}
-
 #[cfg(test)]
 mod tests {
     use super::Utf8Decoder;