RSA is an assymetric cryptosystem used widely to secure communication between clients and servers.
Open Tibia version > 7.6 uses 128bytes RSA.
To generate a new RSA key-pair and PEM file you can use our PEM generator tool. The tool does not output errors, but will generate new prime numbers for P,Q if either is invalid. The requirements for primes P,Q are that P and Q are both 512 bits in size, are prime numbers, and P != Q.