Маленькая прога, шифрующая .txt через XOR со свитчами /s /d шифрование и дешифрование соотвественно.
| Код |
CODE SEGMENT
ORG 100h
ASSUME cs:code, ds:code
Main:
mov dx, OFFSET cmdline
call CmdTail
mov si, dx
mov di, OFFSET param
Pass:
movsb
cmp byte ptr [si], 20h
jne Pass
add si, 1
mov di, OFFSET filename
Repeat:
movsb
cmp byte ptr [si], 0
jne Repeat
; ------------------------------------
; Open file
; ------------------------------------
mov ah, 3Dh
mov al, 02h
mov dx, OFFSET filename
int 21h
jc Error
mov filenum, ax
; ------------------------------------
; Read file
; ------------------------------------
mov ah, 3Fh
mov bx, filenum
mov cx, bufsize
mov dx, OFFSET buffer
int 21h
jc Error
mov filesize, ax
; ------------------------------------
; Close file
; ------------------------------------
mov ah, 3Eh
mov bx, filenum
int 21h
jc Error
; ------------------------------------
; XOR encryption / decription
; ------------------------------------
mov di, 0
mov si, 0
mov bx, OFFSET buffer
Iter:
xor ax, ax
mov al, [bx + si]
xor al, key
mov [bx + si], al
add si, 1
add di, 1
cmp di, filesize
jne Iter
mov ah, 3Ch
mov al, 02h
mov dx, OFFSET filename
int 21h
jc Error
mov filenum, ax
; ------------------------------------
; Write buffer to file
; ------------------------------------
mov ah, 40h
mov bx, filenum
mov cx, filesize
mov dx, OFFSET buffer
int 21h
jc Error
; ------------------------------------
; Close file
; ------------------------------------
mov ah, 3Eh
mov bx, filenum
int 21h
jc Error
jmp Exit
Error:
mov ah, 09h
mov dx, OFFSET message
int 21h
Exit:
mov ah, 08h
int 21h
int 20h
cmdline DB 129 DUP (?)
param DB 20 DUP (0)
filename DB 20 DUP (" "),0
filenum DW 0
filesize DW 0
bufsize = 1024
buffer DB bufsize DUP (0)
key DB 117
message DB "Error!", '$'
include CmdTail.inc
CODE ENDS
END Main
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