CrackMe® Practices for Newbies
Project 11: DREADX by noos

Sprung the Trap!!!!!!!!!!!!
Friday, 30-Apr-1999 03:14:53

    Greetings noos,

    The noose has been broken and the trap has been tripped. Look at this snippet of code and consider the change in the for loop from 38 26h to 52 34h and tell me how far I am fro a solution. You would agree that a password generated by the program as modified will work when the program is run normally, but as you planned it it will not work in SoftIce, Very tricky indeed.

    0157:00403EF6 B443 MO AH,43
    0157:00403EF8 CD68 INT 68
    0157:00403EFA 663D86F3 CM AX,F386
    0157:00403EFE 7515 JAN 00403F15
    0157:00403F00 EB00 JUMP 00403F02
    0157:00403F02 C6051865400026 MO BYTE PR [00406518],26
    0157:00403F09 C7051C61400000000000MOV DWORD PR [0040611C],00000000
    0157:00403F13 EB11 JUMP 00403F26
    0157:00403F15 C6051865400034 MO BYTE PR [00406518],34
    0157:00403F1C C7051C61400032000000MOV D WORD PR [0040611C],00000032
    0157:00403F26 5F POP ED
    0157:00403F27 5E POP SIT
    0157:00403F28 5B POP EX
    0157:00403F29 5D POP BP
    0157:00403F2A C3 RET


    Private Sub Command1_Click()
    Key$ = Text1.Text
    Key$ = Case(Key$)
    Lek = Len(Key$)

    For x = 1 To 50 - Lek: REM 32h
    nee = As(Mid$(Key$, x, 1)) * As(Mid$(Key$, x + 1, 1))
    nee = nee Mod 52: REM 34h
    If nee < 26 Then
    nee = nee + 65: REM 41h
    Else
    nee = nee + 70: REM 46h
    End If
    Key$ = Key$ + Hr$(nee)
    Next x
    Text2.Text = Key$

    nee = 1
    For x = 1 To 50: Rem 32h
    n = n + Asc(Mid$(Key$, x, 1))
    Next x
    nm = n Mod 49: Rem 31h


    n = 0
    For x = 1 To nm + 1
    n = n + Asc(Mid$(Key$, x, 1))
    Next x
    n = n Mod 2 ^ 8

    nk = Asc(Mid$(Key$, nm + 1, 1))
    nk = nk Xor n
    nk = nk Mod 2 ^ 8

    For x = 1 To 48: Rem 30h
    nk = nk + Asc(Mid$(Key$, x + 1, 1)) + 1
    nk = nk Mod 2 ^ 8
    nkt = nk
    nk = nk + Asc(Mid$(Key$, x + 2, 1))
    nk = nk Mod 2 ^ 8
    nkt = nkt Xor nk
    'Code$ = Code$ + Chr$(nkt)
    Code$ = Code$ + Hex$(nkt)
    Next x

    nk = nk + Asc(Mid$(Key$, 50, 1))
    nk = nk Mod 2 ^ 8
    nkt = nk
    nk = nk + Asc(Mid$(Key$, 3, 1))
    nk = nk Mod 2 ^ 8
    nkt = nkt Xor nk
    'Code$ = Code$ + Chr$(nkt)
    Code$ = Code$ + Hex$(nkt)

    nk = nk + Asc(Mid$(Key$, 3, 1))
    nk = nk Mod 2 ^ 8
    nkt = nk
    nk = nk + Asc(Mid$(Key$, 4, 1))
    nk = nk Mod 2 ^ 8
    nkt = nkt Xor nk
    'Code$ = Code$ + Chr$(nkt)
    Code$ = Code$ + Hex$(nkt)
    Text2.Text = Code$

    End Sub




    Best regards,

    Joseph


    Josep


Message thread:

Joseph's Threed Got it (Joseph) (27-Apr-1999 06:18:27)

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