From a546a246e2fec9d4fc98777203ea773d123f0868 Mon Sep 17 00:00:00 2001
From: callebtc <93376500+callebtc@users.noreply.github.com>
Date: Fri, 23 Feb 2024 17:26:46 +0100
Subject: [PATCH] Tests: add step2 domain separated test (#456)

* add step2 domain separated test

* add test3 derived from domain separated outputs

* Fix comment
---
 cashu/core/crypto/b_dhke.py |  2 +-
 tests/test_crypto.py        | 54 +++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/cashu/core/crypto/b_dhke.py b/cashu/core/crypto/b_dhke.py
index ad7ba1aa..78b3510f 100644
--- a/cashu/core/crypto/b_dhke.py
+++ b/cashu/core/crypto/b_dhke.py
@@ -136,7 +136,7 @@ def verify(a: PrivateKey, C: PublicKey, secret_msg: str) -> bool:
     valid = C == Y.mult(a)  # type: ignore
     # BEGIN: BACKWARDS COMPATIBILITY < 0.15.1
     if not valid:
-        return verify_domain_separated(a, C, secret_msg)
+        valid = verify_domain_separated(a, C, secret_msg)
     # END: BACKWARDS COMPATIBILITY < 0.15.1
     return valid
 
diff --git a/tests/test_crypto.py b/tests/test_crypto.py
index a74e8b56..279145a6 100644
--- a/tests/test_crypto.py
+++ b/tests/test_crypto.py
@@ -94,6 +94,7 @@ def test_step2():
 
 def test_step3():
     # C = C_ - A.mult(r)
+    # C_ from test_step2
     C_ = PublicKey(
         bytes.fromhex(
             "02a9acc1e48c25eeeb9289b5031cc57da9fe72f3fe2861d264bdc074209b107ba2"
@@ -352,6 +353,59 @@ def test_step1_domain_separated():
     )
 
 
+def test_step2_domain_separated():
+    B_, _ = step1_alice_domain_separated(
+        "test_message",
+        blinding_factor=PrivateKey(
+            privkey=bytes.fromhex(
+                "0000000000000000000000000000000000000000000000000000000000000001"
+            ),
+            raw=True,
+        ),
+    )
+    a = PrivateKey(
+        privkey=bytes.fromhex(
+            "0000000000000000000000000000000000000000000000000000000000000001"
+        ),
+        raw=True,
+    )
+    C_, e, s = step2_bob(B_, a)
+    assert (
+        C_.serialize().hex()
+        == "025cc16fe33b953e2ace39653efb3e7a7049711ae1d8a2f7a9108753f1cdea742b"
+    )
+
+
+def test_step3_domain_separated():
+    # C = C_ - A.mult(r)
+    # C_ from test_step2
+    C_ = PublicKey(
+        bytes.fromhex(
+            "025cc16fe33b953e2ace39653efb3e7a7049711ae1d8a2f7a9108753f1cdea742b"
+        ),
+        raw=True,
+    )
+    r = PrivateKey(
+        privkey=bytes.fromhex(
+            "0000000000000000000000000000000000000000000000000000000000000001"
+        )
+    )
+
+    A = PublicKey(
+        pubkey=b"\x02"
+        + bytes.fromhex(
+            "0000000000000000000000000000000000000000000000000000000000000001",
+        ),
+        raw=True,
+    )
+    C = step3_alice(C_, r, A)
+
+    assert (
+        C.serialize().hex()
+        == "0271bf0d702dbad86cbe0af3ab2bfba70a0338f22728e412d88a830ed0580b9de4"
+    )
+
+
 def test_dleq_carol_verify_from_bob_domain_separated():
     a = PrivateKey(
         privkey=bytes.fromhex(