xor.c

#include <stdio.h>
#include <Windows.h>

IN PBYTE Xor(IN PBYTE pShellcode, IN SIZE_T sShellsize,IN BYTE Key){
    for(size_t i =0;i<sShellsize;i++){
        pShellcode[i] = pShellcode[i]^(Key+i);
    }
    return pShellcode;
}

int main(){
    unsigned char Data[] = {
        0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x61, 0x20, 0x70, 0x6C,
        0x61, 0x69, 0x6E, 0x20, 0x74, 0x65, 0x78, 0x74, 0x20, 0x73, 0x74, 0x72,
        0x69, 0x6E, 0x67, 0x2C, 0x20, 0x77, 0x65, 0x27, 0x6C, 0x6C, 0x20, 0x74,
        0x72, 0x79, 0x20, 0x74, 0x6F, 0x20, 0x65, 0x6E, 0x63, 0x72, 0x79, 0x70,
        0x74, 0x2F, 0x64, 0x65, 0x63, 0x72, 0x79, 0x70, 0x74, 0x20, 0x21
    };

    printf("Before Encryption: %s  \n\n",Data);

    IN PBYTE result = Xor(Data,sizeof(Data),0x23);

    printf("Result: %s \n\n",result);
}