change hashing order

jjanku · May 6, 2023 · 83286f8 · 83286f8
1 parent 514969b
commit 83286f8
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Showing 4 changed files with 12 additions and 12 deletions.
diff --git a/README.md b/README.md
@@ -15,15 +15,15 @@ This is the card reader app for [MultiSchnorrApplet](https://github.com/jjanku/M
 ```json
 {
     "group": {
-        "x": 82621371836311322635731610237257798577123535778674168916413120265184559472745,
-        "y": 21073772193838990103938873926270519023402430518253746786624584882368307768791
+        "x": 97451645805052459860544257111023732257189445793566253538963642236580295025715,
+        "y": 108036769450804252195526975423364810282508296824311571541272318567742502569515
     },
     "message": "68656c6c6f000000000000000000000000000000000000000000000000000000",
     "nonce": {
-        "x": 28362538501509449895377600989128143307925603662865794767456834195405898871613,
-        "y": 16208392399936672946292064678176285964271568821992841796429050116123184365933
+        "x": 49759968054553596793774934369901300558457422800809412179313891716327499250464,
+        "y": 10595451351086868087048689286043643391031486060528063929912762467167368993502
     },
-    "signature": 104434989019765740973662633870938994847065819938220884369704931829053739864387
+    "signature": 15093668512161333926586696895604108962007543668405816918671093546412761219977
 }
 ```
 

diff --git a/app/src/main/java/com/example/multischnorrreader/crypto/Signature.kt b/app/src/main/java/com/example/multischnorrreader/crypto/Signature.kt
@@ -12,9 +12,9 @@ data class Signature(val nonce: ECPoint, val value: BigInteger) {
         challengeNonce: ECPoint = nonce
     ): Boolean {
         val challenge = MessageDigest.getInstance("SHA-256").run {
+            update(challengeNonce.getEncoded(false))
             update(challengeKey.getEncoded(false))
             update(msg)
-            update(challengeNonce.getEncoded(false))
             BigInteger(1, digest())
         }
         return value * SchemeParameters.ec.g == nonce + challenge * key

diff --git a/app/src/test/java/com/example/multischnorrreader/applet.jar b/app/src/test/java/com/example/multischnorrreader/applet.jar
diff --git a/verify.sage b/verify.sage
@@ -20,15 +20,15 @@ COORD_LEN = (int(p).bit_length() + 7) // 8
 data_json = '''
 {
     "group": {
-        "x": 82621371836311322635731610237257798577123535778674168916413120265184559472745,
-        "y": 21073772193838990103938873926270519023402430518253746786624584882368307768791
+        "x": 97451645805052459860544257111023732257189445793566253538963642236580295025715,
+        "y": 108036769450804252195526975423364810282508296824311571541272318567742502569515
     },
     "message": "68656c6c6f000000000000000000000000000000000000000000000000000000",
     "nonce": {
-        "x": 28362538501509449895377600989128143307925603662865794767456834195405898871613,
-        "y": 16208392399936672946292064678176285964271568821992841796429050116123184365933
+        "x": 49759968054553596793774934369901300558457422800809412179313891716327499250464,
+        "y": 10595451351086868087048689286043643391031486060528063929912762467167368993502
     },
-    "signature": 104434989019765740973662633870938994847065819938220884369704931829053739864387
+    "signature": 15093668512161333926586696895604108962007543668405816918671093546412761219977
 }
 '''
 
@@ -43,6 +43,6 @@ X = E(data['group']['x'], data['group']['y'])
 R = E(data['nonce']['x'], data['nonce']['y'])
 m = bytes.fromhex(data['message'])
 s = data['signature']
-c = int.from_bytes(sha256(encode_point(X) + m + encode_point(R)).digest())
+c = int.from_bytes(sha256(encode_point(R) + encode_point(X) + m).digest())
 
 assert s * G == R + c * X