Test expand_message_xmd

Author: webmaster128

src/hash_to_field.rs

@@ -143,3 +143,119 @@ where
         b_vals
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sha2::Sha256;
+
+    // Except introducing new internal variables, expand_message_xmd did not change
+    // between draft 7 and draft 8 (https://tools.ietf.org/rfcdiff?difftype=--hwdiff&url2=draft-irtf-cfrg-hash-to-curve-08.txt).
+    // So we use draft 8 test vectors.
+
+    /// From https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-08#appendix-I.1
+    #[test]
+    fn expand_message_xmd_works_for_draft8_testvectors_sha256() {
+        let dst = b"QUUX-V01-CS02-with-expander";
+
+        let msg = b"";
+        let len_in_bytes = 0x20;
+        let uniform_bytes =
+            hex::decode("f659819a6473c1835b25ea59e3d38914c98b374f0970b7e4c92181df928fca88")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"abc";
+        let len_in_bytes = 0x20;
+        let uniform_bytes =
+            hex::decode("1c38f7c211ef233367b2420d04798fa4698080a8901021a795a1151775fe4da7")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"abcdef0123456789";
+        let len_in_bytes = 0x20;
+        let uniform_bytes =
+            hex::decode("8f7e7b66791f0da0dbb5ec7c22ec637f79758c0a48170bfb7c4611bd304ece89")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"q128_qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq";
+        let len_in_bytes = 0x20;
+        let uniform_bytes =
+            hex::decode("72d5aa5ec810370d1f0013c0df2f1d65699494ee2a39f72e1716b1b964e1c642")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"a512_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
+        let len_in_bytes = 0x20;
+        let uniform_bytes =
+            hex::decode("3b8e704fc48336aca4c2a12195b720882f2162a4b7b13a9c350db46f429b771b")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"";
+        let len_in_bytes = 0x80;
+        let uniform_bytes =
+            hex::decode("8bcffd1a3cae24cf9cd7ab85628fd111bb17e3739d3b53f89580d217aa79526f1708354a76a402d3569d6a9d19ef3de4d0b991e4f54b9f20dcde9b95a66824cbdf6c1a963a1913d43fd7ac443a02fc5d9d8d77e2071b86ab114a9f34150954a7531da568a1ea8c760861c0cde2005afc2c114042ee7b5848f5303f0611cf297f")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"abc";
+        let len_in_bytes = 0x80;
+        let uniform_bytes =
+            hex::decode("fe994ec51bdaa821598047b3121c149b364b178606d5e72bfbb713933acc29c186f316baecf7ea22212f2496ef3f785a27e84a40d8b299cec56032763eceeff4c61bd1fe65ed81decafff4a31d0198619c0aa0c6c51fca15520789925e813dcfd318b542f8799441271f4db9ee3b8092a7a2e8d5b75b73e28fb1ab6b4573c192")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"abcdef0123456789";
+        let len_in_bytes = 0x80;
+        let uniform_bytes =
+            hex::decode("c9ec7941811b1e19ce98e21db28d22259354d4d0643e301175e2f474e030d32694e9dd5520dde93f3600d8edad94e5c364903088a7228cc9eff685d7eaac50d5a5a8229d083b51de4ccc3733917f4b9535a819b445814890b7029b5de805bf62b33a4dc7e24acdf2c924e9fe50d55a6b832c8c84c7f82474b34e48c6d43867be")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"q128_qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq";
+        let len_in_bytes = 0x80;
+        let uniform_bytes =
+            hex::decode("48e256ddba722053ba462b2b93351fc966026e6d6db493189798181c5f3feea377b5a6f1d8368d7453faef715f9aecb078cd402cbd548c0e179c4ed1e4c7e5b048e0a39d31817b5b24f50db58bb3720fe96ba53db947842120a068816ac05c159bb5266c63658b4f000cbf87b1209a225def8ef1dca917bcda79a1e42acd8069")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+
+        let msg = b"a512_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
+        let len_in_bytes = 0x80;
+        let uniform_bytes =
+            hex::decode("396962db47f749ec3b5042ce2452b619607f27fd3939ece2746a7614fb83a1d097f554df3927b084e55de92c7871430d6b95c2a13896d8a33bc48587b1f66d21b128a1a8240d5b0c26dfe795a1a842a0807bb148b77c2ef82ed4b6c9f7fcb732e7f94466c8b51e52bf378fba044a31f5cb44583a892f5969dcd73b3fa128816e")
+                .unwrap();
+        assert_eq!(
+            ExpandMsgXmd::<Sha256>::expand_message(msg, dst, len_in_bytes),
+            uniform_bytes
+        );
+    }
+}