Encyrption keys in Zephir extension?

Any raw-string in a .so library or DLL can be easily viewed using an utility like 'strings' on Linux/Mac or Hexdump on Windows:

strings ext/modules/test.so

So putting your passwords there would only protect you against newbies. However you can create the passwords by using some algorithm that builds the strings at runtime:

let map = [0x77, 0x7e, 0x7d, 0x6a, 0x6d, 0x77, 0x6f, 0x79], password = "";
for key, value in map {
        if (key + 1) & 1 {
                let password .= value - 10;
        } else {
                let password .= value - 5;
        }
}

The above algorithm is very basic, however it requires a disassembler to find the password out which increases the level of those who want to read it.