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[旧帖] [一段数据效验算法：求大牛看看这是什么效验算法] 0.00雪花
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发表于: 2011-7-21 14:21
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我逆向时程序的一段数据效验算法，求大牛看看叫啥？
容易破解不？
int __cdecl CalcSum(int a1, unsigned int len)
{
unsigned int sum; // eax@1
int addr; // edx@1
unsigned int joro; // ebx@1
signed int tmp; // ecx@6
addr = a1;
joro = 0;
sum = 0;
if ( len )
{
do
{
if ( joro & 1 )
tmp = ~(*(_BYTE *)addr ^ (sum >> 5) ^ (sum << 11));
else
tmp = *(_BYTE *)addr ^ (sum >> 3) ^ (sum << 7);
sum ^= tmp;
++addr;
++joro;
}
while ( joro < len );
}
return sum & 0x7FFFFFFF;
}
求大牛指点下，小弟感激不尽
容易破解不？
int __cdecl CalcSum(int a1, unsigned int len)
{
unsigned int sum; // eax@1
int addr; // edx@1
unsigned int joro; // ebx@1
signed int tmp; // ecx@6
addr = a1;
joro = 0;
sum = 0;
if ( len )
{
do
{
if ( joro & 1 )
tmp = ~(*(_BYTE *)addr ^ (sum >> 5) ^ (sum << 11));
else
tmp = *(_BYTE *)addr ^ (sum >> 3) ^ (sum << 7);
sum ^= tmp;
++addr;
++joro;
}
while ( joro < len );
}
return sum & 0x7FFFFFFF;
}
求大牛指点下，小弟感激不尽
