commit 2472be710f8518caab1f62999c50970b475f162f
Author: Angel Yankov <angel.yankov@suse.com>
Date:   Wed May 28 16:17:10 2025 +0300

    Fix ElGamal side channel issue

Index: cryptopp-CRYPTOPP_8_9_0/pubkey.h
===================================================================
--- cryptopp-CRYPTOPP_8_9_0.orig/pubkey.h
+++ cryptopp-CRYPTOPP_8_9_0/pubkey.h
@@ -1855,7 +1855,14 @@ public:
 			SecByteBlock derivedKey(encAlg.GetSymmetricKeyLength(encAlg.GetMaxSymmetricPlaintextLength(ciphertextLength)));
 			derivAlg.Derive(params, derivedKey, derivedKey.size(), z, q, parameters);
 
-			return encAlg.SymmetricDecrypt(derivedKey, ciphertext, ciphertextLength, plaintext, parameters);
+                        DecodingResult res =  encAlg.SymmetricDecrypt(derivedKey, ciphertext, ciphertextLength, plaintext, parameters);
+                        Element z2 = agreeAlg.AgreeWithStaticPrivateKey(params, q, true, key.GetPrivateExponent());
+                        if (z == z2) {
+                        } else {
+                                return DecodingResult();
+                        }
+                        return res;
+
 		}
 		catch (DL_BadElement &)
 		{