From f28f358aa60f450d0f6e261f051f33ca5f6e7af1 Mon Sep 17 00:00:00 2001
From: Nick Johnson <nick@yonson.dev>
Date: Mon, 4 Mar 2024 08:51:20 -0800
Subject: [PATCH] Add longer inputs and outputs test

---
 src/hkdf.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/src/hkdf.rs b/src/hkdf.rs
index 77020d2..675e660 100644
--- a/src/hkdf.rs
+++ b/src/hkdf.rs
@@ -50,6 +50,7 @@ impl Hkdf {
             return Err(InvalidLength);
         }
 
+        // Counter starts at "1" based on RFC5869 spec and is committed to in the hash.
         let mut counter = 1u8;
         // Ceiling calculation for the total number of hashes required for the expand.
         let total_hashes = (okm.len() + HASH_LENGTH_BYTES - 1) / HASH_LENGTH_BYTES;
@@ -108,4 +109,26 @@ mod tests {
             "3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865"
         );
     }
+
+    #[test]
+    fn test_longer_inputs_outputs() {
+        let salt = hex::decode(
+            "606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeaf"
+        ).unwrap();
+        let ikm = hex::decode(
+            "000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f"
+        ).unwrap();
+        let info = hex::decode(
+            "b0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff"
+        ).unwrap();
+
+        let hkdf = Hkdf::extract(&salt, &ikm);
+        let mut okm = [0u8; 82];
+        hkdf.expand(&info, &mut okm).unwrap();
+
+        assert_eq!(
+            hex::encode(okm),
+            "b11e398dc80327a1c8e7f78c596a49344f012eda2d4efad8a050cc4c19afa97c59045a99cac7827271cb41c65e590e09da3275600c2f09b8367793a9aca3db71cc30c58179ec3e87c14c01d5c1f3434f1d87"
+        );
+    }
 }