54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
#include <stdint.h>
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#include <stdio.h>
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#include <sys/types.h>
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char test[] = "hacklab{ ";
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unsigned int start_key=2723;
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//paste flag.enc here (add ", 0x")
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char text[] = {0x2c, 0x1d, 0x5d, 0xb1, 0x67, 0x85, 0x0f, 0x52, 0x69, 0x93, 0x1c, 0x2d, 0x79, 0xf0, 0x4b, 0xc2, 0x64, 0xbd, 0x0f, 0xda, 0x95, 0x88, 0x16, 0x0c, 0x2f, 0x5e, 0x9e, 0x68, 0xee, 0xf4, 0x1e, 0xb6, 0xb8, 0xa7, 0x7d, 0x43, 0xa8, 0x00, 0x51, 0xc4, 0xfe, 0x54, 0x10, 0x26, 0xf1, 0xd3, 0x2b};
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typedef uint8_t byte;
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byte scramble_key(unsigned int *key_input){
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*key_input = (*key_input * 0x41c64e6d + 0x3039) % 0x80000000;
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return *(byte *)((long)key_input + 3) ^
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(byte)*key_input ^ *(byte *)((long)key_input + 1) ^ *(byte *)((long)key_input + 2);
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}
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void encrypt(uint32_t key,char *text,ulong len)
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{
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byte bVar1;
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uint32_t local_1c [4];
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int i;
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local_1c[0] = key;
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for (i = 0; (ulong)(long)i < len; i = i + 1) {
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bVar1 = scramble_key(local_1c);
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text[i] = bVar1 ^ text[i];
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text[i] = text[i] + 'O';
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}
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return;
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}
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void decrypt(uint32_t key,char *text,ulong len)
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{
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byte bVar1;
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uint32_t local_1c [4];
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int i;
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local_1c[0] = key;
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for (i = 0; (ulong)(long)i < len; i = i + 1) {
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bVar1 = scramble_key(local_1c);
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text[i] = text[i] - 'O';
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text[i] = bVar1 ^ text[i];
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}
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return;
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}
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int main(int argc, char** args){
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decrypt(start_key, text, sizeof(text));
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for(uint8_t i=0; i<sizeof(text); i++)
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printf("%c", text[i]);
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}
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