破解软件：桌面钢笔v2.0
下载地址：http://www.arongsoft.net/soft/4533.htm，阿榕软件园
调试工具：OD，PEID
破解平台：XP
软件介绍：运行本桌面钢笔V2.0后，桌面会出现一支钢笔图形，按住鼠标左键移动鼠标可在桌面随意写
字画画。
破解说明：今天闲得无聊，拿来试试手，失误之处请见谅。
运行软件，提示注册，随便输入点注册，出现错误提示。PEID查有UPX壳，弱壳，不想脱了，带壳调试。
用OD附加进程，然后用Ultra String Refrence插件查找错误信息，一直向上看来到判断子过程的入口处：
0041C02D push ebp
0041C02E mov ebp,esp
0041C030 sub esp,2C
0041C036 push 0
0041C03B mov ebx,6C4
0041C040 call 桌面钢笔.0041D199
0041C045 add esp,4
0041C048 push 80000301
0041C04D push 0
0041C04F push eax
0041C050 push 1
0041C055 mov ebx,164
0041C05A call 桌面钢笔.0041D199
0041C05F add esp,10
0041C062 mov dword ptr ss:[ebp-C],eax
0041C065 mov dword ptr ss:[ebp-8],edx
0041C068 fld qword ptr ss:[ebp-C] ; 机器码入栈，2111755623
0041C06B fmul qword ptr ds:[412FC0] ; 乘[412FC0]的浮点值46398，得
9.7981237395954E+13
0041C071 fstp qword ptr ss:[ebp-14] ; 出栈
0041C074 fld qword ptr ss:[ebp-14] ; 入栈
0041C077 fadd qword ptr ds:[412FC8] ; 加浮点值1111,结果为9.7981237397065E+13
0041C07D fstp qword ptr ss:[ebp-1C] ; 出栈
0041C080 fld qword ptr ss:[ebp-1C] ; 入栈
0041C083 call 桌面钢笔.0041A381 ; 取浮点的结果，返回EAX值。跟入
0041A381 push ebp
0041A382 mov ebp,esp
0041A384 add esp,-0C
0041A387 fstcw word ptr ss:[ebp-2]
0041A38A mov ax,word ptr ss:[ebp-2]
0041A38E or ah,0C
0041A391 mov word ptr ss:[ebp-4],ax
0041A395 fldcw word ptr ss:[ebp-4]
0041A398 fistp qword ptr ss:[ebp-C] ; 浮点结果出栈，保存在[ebp-c]，十六进制
为591D08D98649
0041A39B fldcw word ptr ss:[ebp-2]
0041A39E mov eax,dword ptr ss:[ebp-C] ; 将结果的后8位赋值给eax，即08D98649
0041A3A1 mov edx,dword ptr ss:[ebp-8]
0041A3A4 mov esp,ebp
0041A3A6 pop ebp
0041A3A7 retn
继续跟踪：
0041C088 push 80000301
0041C08D push 0
0041C08F push eax ; EAX=08D98649
0041C090 push 1
0041C095 mov ebx,1D4
0041C09A call 桌面钢笔.0041D199 ; 将EAX的值转化为字符，即“8D98649”
0041C09F add esp,10
0041C0A2 mov dword ptr ss:[ebp-20],eax
0041C0A5 push 80000004
0041C0AA push 0
0041C0AC mov eax,dword ptr ss:[ebp-20]
0041C0AF test eax,eax
0041C0B1 jnz short 桌面钢笔.0041C0B8
0041C0B3 mov eax,桌面钢笔.0040F1D3
0041C0B8 push eax
0041C0B9 push 1
0041C0BE mov ebx,168
0041C0C3 call 桌面钢笔.0041D199
0041C0C8 add esp,10
0041C0CB mov dword ptr ss:[ebp-24],eax
0041C0CE mov ebx,dword ptr ss:[ebp-20]
0041C0D1 test ebx,ebx
0041C0D3 je short 桌面钢笔.0041C0DE
0041C0D5 push ebx
0041C0D6 call 桌面钢笔.0041D181
0041C0DB add esp,4
0041C0DE push -1
0041C0E0 push 8
0041C0E2 push 1601009F
0041C0E7 push 5201009B
0041C0EC call 桌面钢笔.0041D1A5 ; 获取输入码第一部分
0041C0F1 add esp,10
0041C0F4 mov dword ptr ss:[ebp-28],eax
0041C0F7 mov eax,dword ptr ss:[ebp-24]
0041C0FA push eax ; 正确码
0041C0FB push dword ptr ss:[ebp-28] ; 输入码
0041C0FE call 桌面钢笔.0041BF09 ; 比较是否相等
0041C103 add esp,8
0041C106 cmp eax,0
0041C109 mov eax,0
0041C10E sete al ; 相等则置1
0041C111 mov dword ptr ss:[ebp-2C],eax ; [ebp-2c]标志位
0041C114 mov ebx,dword ptr ss:[ebp-28]
0041C117 test ebx,ebx
0041C119 je short 桌面钢笔.0041C124
0041C11B push ebx
0041C11C call 桌面钢笔.0041D181
0041C121 add esp,4
0041C124 mov ebx,dword ptr ss:[ebp-24]
0041C127 test ebx,ebx
0041C129 je short 桌面钢笔.0041C134
0041C12B push ebx
0041C12C call 桌面钢笔.0041D181
0041C131 add esp,4
0041C134 cmp dword ptr ss:[ebp-2C],0
0041C138 je 桌面钢笔.0041C4A5 ; 暴破点一
0041C13E push 0
0041C143 mov ebx,6C4
0041C148 call 桌面钢笔.0041D199
0041C14D add esp,4
0041C150 push 80000301
0041C155 push 0
0041C157 push eax
0041C158 push 1
0041C15D mov ebx,164
0041C162 call 桌面钢笔.0041D199
0041C167 add esp,10
0041C16A mov dword ptr ss:[ebp-C],eax
0041C16D mov dword ptr ss:[ebp-8],edx
0041C170 fld qword ptr ss:[ebp-C] ; 机器码入栈，2111755623
0041C173 fmul qword ptr ds:[412FD0] ; 乘12987，得2.7425370275901E+13
0041C179 fstp qword ptr ss:[ebp-14]
0041C17C fld qword ptr ss:[ebp-14]
0041C17F fadd qword ptr ds:[412FD8] ; 加2222，得2.7425370278123E+13
0041C185 fstp qword ptr ss:[ebp-1C]
0041C188 fld qword ptr ss:[ebp-1C]
0041C18B call 桌面钢笔.0041A381 ; 取浮点的结果，返回EAX值。略
0041C190 push 80000301
0041C195 push 0
0041C197 push eax ; EAX=777408EB
0041C198 push 1
0041C19D mov ebx,1D4
0041C1A2 call 桌面钢笔.0041D199 ; 将EAX的值转化为字符，即“777408EB
”
0041C1A7 add esp,10
0041C1AA mov dword ptr ss:[ebp-20],eax
0041C1AD push 80000004
0041C1B2 push 0
0041C1B4 mov eax,dword ptr ss:[ebp-20]
0041C1B7 test eax,eax
0041C1B9 jnz short 桌面钢笔.0041C1C0
0041C1BB mov eax,桌面钢笔.0040F1D3
0041C1C0 push eax
0041C1C1 push 1
0041C1C6 mov ebx,168
0041C1CB call 桌面钢笔.0041D199
0041C1D0 add esp,10
0041C1D3 mov dword ptr ss:[ebp-24],eax
0041C1D6 mov ebx,dword ptr ss:[ebp-20]
0041C1D9 test ebx,ebx
0041C1DB je short 桌面钢笔.0041C1E6
0041C1DD push ebx
0041C1DE call 桌面钢笔.0041D181
0041C1E3 add esp,4
0041C1E6 push -1
0041C1E8 push 8
0041C1EA push 160100A1
0041C1EF push 5201009B
0041C1F4 call 桌面钢笔.0041D1A5 ; 获得输入码第二部分
0041C1F9 add esp,10
0041C1FC mov dword ptr ss:[ebp-28],eax
0041C1FF mov eax,dword ptr ss:[ebp-24]
0041C202 push eax ; 正确码
0041C203 push dword ptr ss:[ebp-28] ; 输入码
0041C206 call 桌面钢笔.0041BF09 ; 比较是否相等
0041C20B add esp,8
0041C20E cmp eax,0
0041C211 mov eax,0
0041C216 sete al ; 相等则置1
0041C219 mov dword ptr ss:[ebp-2C],eax ; [ebp-2c]标志位
0041C21C mov ebx,dword ptr ss:[ebp-28]
0041C21F test ebx,ebx
0041C221 je short 桌面钢笔.0041C22C
0041C223 push ebx
0041C224 call 桌面钢笔.0041D181
0041C229 add esp,4
0041C22C mov ebx,dword ptr ss:[ebp-24]
0041C22F test ebx,ebx
0041C231 je short 桌面钢笔.0041C23C
0041C233 push ebx
0041C234 call 桌面钢笔.0041D181
0041C239 add esp,4
0041C23C cmp dword ptr ss:[ebp-2C],0
0041C240 je 桌面钢笔.0041C42F ; 暴破点二
0041C246 push 0
0041C24B mov ebx,6C4
0041C250 call 桌面钢笔.0041D199
0041C255 add esp,4
0041C258 push 80000301
0041C25D push 0
0041C25F push eax
0041C260 push 1
0041C265 mov ebx,164
0041C26A call 桌面钢笔.0041D199
0041C26F add esp,10
0041C272 mov dword ptr ss:[ebp-C],eax
0041C275 mov dword ptr ss:[ebp-8],edx
0041C278 fld qword ptr ss:[ebp-C] ; 机器码入栈，2111755623
0041C27B fmul qword ptr ds:[412FE0] ; 乘91548，得1.93403026976832E+14
0041C281 fstp qword ptr ss:[ebp-14]
0041C284 fld qword ptr ss:[ebp-14]
0041C287 fadd qword ptr ds:[412FE8] ; 加3333，得1.93403026980165E+14
0041C28D fstp qword ptr ss:[ebp-1C]
0041C290 fld qword ptr ss:[ebp-1C]
0041C293 call 桌面钢笔.0041A381 ; 取浮点的结果，返回EAX值。略
0041C298 push 80000301
0041C29D push 0
0041C29F push eax ; EAX=26B8BD45
0041C2A0 push 1
0041C2A5 mov ebx,1D4
0041C2AA call 桌面钢笔.0041D199 ; 将EAX的值转化为字符，即“26B8BD45
”
0041C2AF add esp,10
0041C2B2 mov dword ptr ss:[ebp-20],eax
0041C2B5 push 80000004
0041C2BA push 0
0041C2BC mov eax,dword ptr ss:[ebp-20]
0041C2BF test eax,eax
0041C2C1 jnz short 桌面钢笔.0041C2C8
0041C2C3 mov eax,桌面钢笔.0040F1D3
0041C2C8 push eax
0041C2C9 push 1
0041C2CE mov ebx,168
0041C2D3 call 桌面钢笔.0041D199
0041C2D8 add esp,10
0041C2DB mov dword ptr ss:[ebp-24],eax
0041C2DE mov ebx,dword ptr ss:[ebp-20]
0041C2E1 test ebx,ebx
0041C2E3 je short 桌面钢笔.0041C2EE
0041C2E5 push ebx
0041C2E6 call 桌面钢笔.0041D181
0041C2EB add esp,4
0041C2EE push -1
0041C2F0 push 8
0041C2F2 push 160100A0
0041C2F7 push 5201009B
0041C2FC call 桌面钢笔.0041D1A5 ; 获得输入码第三部分
0041C301 add esp,10
0041C304 mov dword ptr ss:[ebp-28],eax
0041C307 mov eax,dword ptr ss:[ebp-24]
0041C30A push eax ; 正确码
0041C30B push dword ptr ss:[ebp-28] ; 输入码
0041C30E call 桌面钢笔.0041BF09 ; 比较是否相等
0041C313 add esp,8
0041C316 cmp eax,0
0041C319 mov eax,0
0041C31E sete al ; 相等则置1
0041C321 mov dword ptr ss:[ebp-2C],eax ; [ebp-2c]标志位
0041C324 mov ebx,dword ptr ss:[ebp-28]
0041C327 test ebx,ebx
0041C329 je short 桌面钢笔.0041C334
0041C32B push ebx
0041C32C call 桌面钢笔.0041D181
0041C331 add esp,4
0041C334 mov ebx,dword ptr ss:[ebp-24]
0041C337 test ebx,ebx
0041C339 je short 桌面钢笔.0041C344
0041C33B push ebx
0041C33C call 桌面钢笔.0041D181
0041C341 add esp,4
0041C344 cmp dword ptr ss:[ebp-2C],0
0041C348 je 桌面钢笔.0041C3B9 ; 暴破点三
0041C34E call 桌面钢笔.0041C51A
0041C353 push 80000004
0041C358 push 0
0041C35A push 桌面钢笔.00412FF0
0041C35F push 80000301
0041C364 push 0
0041C366 push 40
0041C36B push 80000004
0041C370 push 0
0041C372 push 桌面钢笔.00413001 ; 恭喜你，你已经成功注册此软件
0041C377 push 3
0041C37C mov ebx,300
0041C381 call 桌面钢笔.0041D199
0041C386 add esp,28
0041C389 push 10001
0041C38E push 601009C
0041C393 push 5201009B
0041C398 push 1
0041C39D mov ebx,360
0041C3A2 call 桌面钢笔.0041D199
0041C3A7 add esp,10
0041C3AA push 0
0041C3AC call 桌面钢笔.0041D169
0041C3B1 add esp,4
0041C3B4 jmp 桌面钢笔.0041C42A
小结：分三部分采用浮点计算(用十进制)注册码。算完后取十六进制的后8位结果为正确码。
SN1=2111755623*46398+1111=591D08D98649，正确码为8D98649(首位0不要)
SN2=2111755623*12987+2222=18F1777408EB，正确码为777408EB
SN3=2111755623*91548+3333=AFE626B8BD45，正确码为26B8BD45
即注册码为8D98649-777408EB-26B8BD45