I am learning basic Xor encryption of files, so I am trying to create a simple program to encrypt all of the files in the current directory. Heres part of the program, with the result of Int21h Function4Eh (FindFirstFile) stored in a variable named FNAME.
After opening the file like this for read/write, I need to store the number of bytes in the file in a variable named BUFFER. However, the only way I know of doing this is Int21h Fnction3F (ReadFromFile). This requires the number of bytes to be read set in CX. Obviously I don't know how many there will be.
Can anyone help please?