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

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);
+    }
+}