Create multi_sig.py

src/security/multi_sig.py

@@ -0,0 +1,45 @@
+import hashlib
+import ecdsa
+
+class MultiSig:
+    def __init__(self, num_signers):
+        self.num_signers = num_signers
+        self.signers = [ecdsa.SigningKey.from_secret_exponent(i, curve=ecdsa.SECP256k1) for i in range(1, num_signers + 1)]
+
+    def sign(self, message, signer_index):
+        signer = self.signers[signer_index - 1]
+        signature = signer.sign(hashlib.sha256(message.encode()).digest())
+        return signature
+
+    def verify(self, message, signature, signer_index):
+        signer = self.signers[signer_index - 1]
+        verifying_key = signer.get_verifying_key()
+        try:
+            verifying_key.verify(signature, hashlib.sha256(message.encode()).digest())
+            return True
+        except ecdsa.BadSignatureError:
+            return False
+
+    def combine_signatures(self, signatures):
+        combined_signature = b''
+        for signature in signatures:
+            combined_signature += signature
+        return combined_signature
+
+    def verify_combined(self, message, combined_signature):
+        for i in range(self.num_signers):
+            signer = self.signers[i]
+            verifying_key = signer.get_verifying_key()
+            try:
+                verifying_key.verify(combined_signature, hashlib.sha256(message.encode()).digest())
+            except ecdsa.BadSignatureError:
+                return False
+        return True
+
+# Example usage
+if __name__ == "__main__":
+    multi_sig = MultiSig(num_signers=3)
+    message = "Hello, Multi-Sig!"
+    signatures = [multi_sig.sign(message, i) for i in range(1, 4)]
+    combined_signature = multi_sig.combine_signatures(signatures)
+    print(multi_sig.verify_combined(message, combined_signature))