Update openssl calls to use EVP interface (#5072)

loginserver/encryption.h

@@ -48,10 +48,20 @@ namespace CryptoHash {
 }
 
 std::string GetEncryptionByModeId(uint32 mode);
+
+// DES-CBC with an all-zero key and IV (EQ login protocol obfuscation, not security).
+// On encrypt, a trailing partial block is zero-padded to the next 8-byte boundary, so
+// buffer_out must be at least ((buffer_in_sz + 7) / 8) * 8 bytes. On decrypt, buffer_in_sz
+// must already be a multiple of 8 or the call returns nullptr.
 const char *eqcrypt_block(const char *buffer_in, size_t buffer_in_sz, char *buffer_out, bool enc);
 std::string eqcrypt_hash(const std::string &username, const std::string &password, int mode);
 bool eqcrypt_verify_hash(const std::string &username, const std::string &password, const std::string &pwhash, int mode);
 
+// OpenSSL 3.0 moved DES behind the "legacy" provider; these load/unload it
+// for the lifetime of the process. No-op when built against mbedtls.
+bool eqcrypt_init();
+void eqcrypt_shutdown();
+
 struct EncryptionResult {
 	std::string password;
 	int         mode = 0;