> Oh, and a fun fact - with the newest cryptography algorithms it's even possible to modify the files without knowing what they contain. If I'm not mistaken it

> Oh, and a fun fact - with the newest cryptography algorithms it's even possible to modify the files without knowing what they contain. If I'm not mistaken it would even be possoble to create a software that can conpute checksums of files without knowing the file contents. To my knowledge, this is only true in a purely academic (not practical) sense at present. There do exist homomorphic encryption schemes but current implementations are ridiculously slow.