Anti-malware and Anti-Virus
Some protocols have multiple algorithms to choose from for e.g., cryptographic purposes. During connection set up, client and server negotiate which one they'll use.
One example is the set up of a TLS connection. During the handshake, the client shares a list of its supported ciphers (the 'ciphersuites'). The server responds by indicating the best one that both sides support.
Aaron's action is considered legal, as you are allowed to make a backup copy of a legal copy of a software, but it can only be used in case the original software is destroyed or unusable.
apply for financial aid for college or grad school.