Use a CALL decrypt in the beginning of V2 to unencrypt the file so your program can run. The value of encryption is readily apparent. Encryption makes it harder for virus scanners to locate your virus. It also hides some text strings located in your program. It is the easiest and shortest way to hide your virus.
Encryption is only one form of concealment.
At least one other virus hooks into the DOS interrupts and alters the output of DIR so the file sizes appear normal. Loading the virus in certain parts of memory allow it to survive warm reboots. There are many stealth techniques, limited only by the virus writer's imagination. So now all the boring stuff is over. The nastiness is contained here.