I was wondering how do hackers use cryptography for bypassing antivirus software.
I don't have some deep understanding on how antivirus software works, but I know that every antivirus has base of signatures, so when we scan .exe file it actually compares signature of .exe with signatures in it's own base, and if it matches, antivirus will identify .exe as virus.
So by applying some cryptographic algorithm on .exe file (using tool "Crypter"), they change signature of .exe, so antivirus can't detect it as malware, right? But concretely, how do they apply cryptograpyic algorithm on .exe file? I saw only in my book how plaintext is crypted.