Add function to BridgeLine to get hashed fingerprint

Cargo.lock

@@ -1252,6 +1252,7 @@ dependencies = [
  "rand 0.8.5",
  "serde",
  "serde_with",
+ "sha1",
  "sha2",
  "statistical",
  "subtle",

crates/lox-library/Cargo.toml

@@ -21,6 +21,7 @@ chrono = "0.4.38"
 rand = { version = "0.8", features = ["std_rng"]}
 serde = "1.0.197"
 serde_with = {version = "3.7.0", features = ["json"]}
+sha1 = "0.10"
 sha2 = "0.10"
 statistical = "1.0.0"
 lazy_static = "1"

crates/lox-library/src/bridge_table.rs

@@ -20,6 +20,7 @@ use curve25519_dalek::scalar::Scalar;
 use rand::RngCore;
 use serde::{Deserialize, Serialize};
 use serde_with::serde_as;
+use sha1::{Digest, Sha1};
 use std::collections::{HashMap, HashSet};
 use std::convert::{TryFrom, TryInto};
 use subtle::ConstantTimeEq;
@@ -50,13 +51,23 @@ pub struct BridgeLine {
     /// fingerprint
     pub uid_fingerprint: u64,
     /// unhashed fingerprint (20-byte bridge ID)
-    pub fingerprint: [u8; 20],
+    pub fingerprint: [u8; 20], // may be changed to a string later
     /// other protocol information, including pluggable transport,
     /// public key, etc.
     #[serde_as(as = "[_; BRIDGE_INFO_BYTES]")]
     pub info: [u8; BRIDGE_INFO_BYTES],
 }
 
+impl BridgeLine {
+    pub fn get_hashed_fingerprint(&self) -> [u8; 20] {
+        let mut hasher = Sha1::new();
+        hasher.update(&self.fingerprint);
+        // If the fingerprint gets changed to a string:
+        //hasher.update(array_bytes::hex2array(&self.fingerprint).unwrap());
+        hasher.finalize().into()
+    }
+}
+
 /// A bucket contains MAX_BRIDGES_PER_BUCKET bridges plus the
 /// information needed to construct a Bucket Reachability credential,
 /// which is a 4-byte date, and a (P,Q) MAC