jiami.asm

实现文件的加密

;输入文件名和密码,对文件内容进行加密.解密方法与加密相同.
; 2008-4-1 zbj 
DATAS SEGMENT
    str1 db 20,?
    fn   db 20 dup(?)
    str2 db 8,?
    ps   db 8 dup(-1)   
    msg1 db 'file name :$'
    msg2 db 13,10,'pass word:$'
    handle dw ?
    buf db 8 dup (?)
DATAS ENDS

CODES SEGMENT
    ASSUME CS:CODES,DS:DATAS
START:
    MOV AX,DATAS
    MOV DS,AX
    mov es,ax
    lea dx,msg1
    mov ah,9
    int 21h
    lea dx,str1
    mov ah,10
    int 21h
    lea bx,fn
    add bl,str1+1
    adc bh,0
    mov byte ptr [bx],0
    lea dx,msg2
    mov ah,9
    int 21h
    lea dx,str2
    mov ah,10
    int 21h
    lea dx,fn
    mov ax,3d02h
    int 21h
    mov handle,ax
  l1:mov bx,handle
     lea dx,buf
     mov cx,8
     mov ah,3fh
     int 21h
     cmp ax,8
     jnz ok
     lea si,ps
     lea di,buf
   l2: lodsb
       xor al,[di]
       stosb
       loop l2
     mov bx,handle
     mov cx,-1
     mov dx,-8
     mov ax,4201h
     int 21h
     mov bx,handle
     lea dx,buf
     mov cx,8
     mov ah,40h
     int 21h
     jmp l1
   ok: mov bx,handle
       mov ah,3eh
       int 21h  
    MOV AH,4CH
    INT 21H
CODES ENDS
    END START