This is my first attempt at a binary protector. Currently, the VM has very little protection, so this should be good for those interested in learning about VM-based obfuscation. I intend on uploading new challenges that feature my protector as I add more features.
GOAL:
- You must find the correct key. Simply patching to get a goodboy message is NOT allowed.
- Bonus points for devirt and explanation of your approach.
- MOST IMPORTANTLY, have fun!
:)
#include <stdio.h>
#pragma GCC push_options
#pragma GCC optimize ("O0")
int isCorrect(unsigned int input)
{
unsigned int key = 0x77259243;
key |= 0x23;
key &= 0x23;
key += 0x843;
key &= 0x5466;
key += 0x843;
key |= 0x234;
int result = 0;
key += 0x63654;
key &= 0x4545;
key |= 0x65466;
key -= 0x5234;
key -= 0x863;
key ^= 0x7;
if (input == 0x743)
result = 1;
key += 0x65363;
key &= 0x75454;
key |= 0x754;
key += 0x1;
key -= 0x1;
key += 0x711;
if (input == 0x972)
result = 1;
key += 0x3643;
key += 0x54;
key |= 0x54;
key |= 0x331;
key |= 0x12;
key += 0x321;
if (input == 0x666)
result = 1;
key -= 0x97;
key += 0x744;
key |= 0x54;
key -= 0x82;
key |= 0x12;
key += 0x223;
if (input == key)
result = 1;
key += 0x7342;
key ^= 0x42;
key ^= 0x744;
unsigned int tempKey2 = 0x7443;
key ^= 0x33;
key |= 0x88;
key += 0x764;
if (input == tempKey2)
result = 1;
return result;
}
#pragma GCC pop_options
int main() {
unsigned int input = 0x0;
printf("Enter Key: ");
scanf("%d", &input);
if (isCorrect(input))
{
printf("Correct Key!\n");
}
else
{
printf("Incorrect Key.\n");
}
return 0;
}
correct key: 299902
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