Assembly Language for Beginners

(nextflipdebug2) #1
8.5. DONGLES
.text:0000D66E jz short loc_D6D1
.text:0000D670 xor ebx, ebx
.text:0000D672 mov al, _C_and_B
.text:0000D677 test al, al
.text:0000D679 jz short loc_D6C0
.text:0000D67B
.text:0000D67B loc_D67B: ; CODE XREF: sys_info+106j
.text:0000D67B mov eax, _3C_or_3E[ebx*4]
.text:0000D682 push eax
.text:0000D683 call SSQ
.text:0000D688 push offset a4g ; "4G"
.text:0000D68D call SSQ
.text:0000D692 push offset a0123456789 ; "0123456789"
.text:0000D697 call SSQ
.text:0000D69C add esp, 0Ch
.text:0000D69F mov edx, answers1[ebx*4]
.text:0000D6A6 cmp eax, edx
.text:0000D6A8 jz short OK
.text:0000D6AA mov ecx, answers2[ebx*4]
.text:0000D6B1 cmp eax, ecx
.text:0000D6B3 jz short OK
.text:0000D6B5 mov al, byte_4016D1[ebx]
.text:0000D6BB inc ebx
.text:0000D6BC test al, al
.text:0000D6BE jnz short loc_D67B
.text:0000D6C0
.text:0000D6C0 loc_D6C0: ; CODE XREF: sys_info+C1j
.text:0000D6C0 inc ds:ctl_port
.text:0000D6C6 xor eax, eax
.text:0000D6C8 mov al, ds:ctl_port
.text:0000D6CD cmp eax, edi
.text:0000D6CF jle short loc_D652
.text:0000D6D1
.text:0000D6D1 loc_D6D1: ; CODE XREF: sys_info+98j
.text:0000D6D1 ; sys_info+B6j
.text:0000D6D1 mov edx, [ebp+var_8]
.text:0000D6D4 inc edx
.text:0000D6D5 mov [ebp+var_8], edx
.text:0000D6D8 cmp edx, 3
.text:0000D6DB jle loc_D641
.text:0000D6E1
.text:0000D6E1 loc_D6E1: ; CODE XREF: sys_info+16j
.text:0000D6E1 ; sys_info+51j ...
.text:0000D6E1 pop ebx
.text:0000D6E2 pop edi
.text:0000D6E3 mov esp, ebp
.text:0000D6E5 pop ebp
.text:0000D6E6 retn
.text:0000D6E8 OK: ; CODE XREF: sys_info+F0j
.text:0000D6E8 ; sys_info+FBj
.text:0000D6E8 mov al, _C_and_B[ebx]
.text:0000D6EE pop ebx
.text:0000D6EF pop edi
.text:0000D6F0 mov ds:ctl_model, al
.text:0000D6F5 mov esp, ebp
.text:0000D6F7 pop ebp
.text:0000D6F8 retn
.text:0000D6F8 sys_info endp

“3C” and “3E” sound familiar: there was a Sentinel Pro dongle by Rainbow with no memory, providing only
one crypto-hashing secret function.


You can read a short description of what hash function is here:2.11 on page 466.

But let’s get back to the program.

So the program can only check the presence or absence of a connected dongle.

No other information can be written to such dongle, as it has no memory. The two-character codes are
commands (we can see how the commands are handled in theSSQC()function) and all other strings are
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