Solver for CSAW CTF 2017 "tablez"

tablEZ_100.py

import struct

# Table dumped from executable
maybe_table = struct.pack ("512B", *[
0x01,0xbb,0x02,0x9b,0x03,0xc4,0x04,0x6c,0x05,0x4a,0x06,
0x2e,0x07,0x22,0x08,0x45,0x09,0x33,0x0a,0xb8,0x0b,0xd5,
0x0c,0x06,0x0d,0x0a,0x0e,0xbc,0x0f,0xfa,0x10,0x79,0x11,
0x24,0x12,0xe1,0x13,0xb2,0x14,0xbf,0x15,0x2c,0x16,0xad,
0x17,0x86,0x18,0x60,0x19,0xa4,0x1a,0xb6,0x1b,0xd8,0x1c,
0x59,0x1d,0x87,0x1e,0x41,0x1f,0x94,0x20,0x77,0x21,0xf0,
0x22,0x4f,0x23,0xcb,0x24,0x61,0x25,0x25,0x26,0xc0,0x27,
0x97,0x28,0x2a,0x29,0x5c,0x2a,0x08,0x2b,0xc9,0x2c,0x9f,
0x2d,0x43,0x2e,0x4e,0x2f,0xcf,0x30,0xf9,0x31,0x3e,0x32,
0x6f,0x33,0x65,0x34,0xe7,0x35,0xc5,0x36,0x39,0x37,0xb7,
0x38,0xef,0x39,0xd0,0x3a,0xc8,0x3b,0x2f,0x3c,0xaa,0x3d,
0xc7,0x3e,0x47,0x3f,0x3c,0x40,0x81,0x41,0x32,0x42,0x49,
0x43,0xd3,0x44,0xa6,0x45,0x96,0x46,0x2b,0x47,0x58,0x48,
0x40,0x49,0xf1,0x4a,0x9c,0x4b,0xee,0x4c,0x1a,0x4d,0x5b,
0x4e,0xc6,0x4f,0xd6,0x50,0x80,0x51,0x2d,0x52,0x6d,0x53,
0x9a,0x54,0x3d,0x55,0xa7,0x56,0x93,0x57,0x84,0x58,0xe0,
0x59,0x12,0x5a,0x3b,0x5b,0xb9,0x5c,0x09,0x5d,0x69,0x5e,
0xba,0x5f,0x99,0x60,0x48,0x61,0x73,0x62,0xb1,0x63,0x7c,
0x64,0x82,0x65,0xbe,0x66,0x27,0x67,0x9d,0x68,0xfb,0x69,
0x67,0x6a,0x7e,0x6b,0xf4,0x6c,0xb3,0x6d,0x05,0x6e,0xc2,
0x6f,0x5f,0x70,0x1b,0x71,0x54,0x72,0x23,0x73,0x71,0x74,
0x11,0x75,0x30,0x76,0xd2,0x77,0xa5,0x78,0x68,0x79,0x9e,
0x7a,0x3f,0x7b,0xf5,0x7c,0x7a,0x7d,0xce,0x7e,0x0b,0x7f,
0x0c,0x80,0x85,0x81,0xde,0x82,0x63,0x83,0x5e,0x84,0x8e,
0x85,0xbd,0x86,0xfe,0x87,0x6a,0x88,0xda,0x89,0x26,0x8a,
0x88,0x8b,0xe8,0x8c,0xac,0x8d,0x03,0x8e,0x62,0x8f,0xa8,
0x90,0xf6,0x91,0xf7,0x92,0x75,0x93,0x6b,0x94,0xc3,0x95,
0x46,0x96,0x51,0x97,0xe6,0x98,0x8f,0x99,0x28,0x9a,0x76,
0x9b,0x5a,0x9c,0x91,0x9d,0xec,0x9e,0x1f,0x9f,0x44,0xa0,
0x52,0xa1,0x01,0xa2,0xfc,0xa3,0x8b,0xa4,0x3a,0xa5,0xa1,
0xa6,0xa3,0xa7,0x16,0xa8,0x10,0xa9,0x14,0xaa,0x50,0xab,
0xca,0xac,0x95,0xad,0x92,0xae,0x4b,0xaf,0x35,0xb0,0x0e,
0xb1,0xb5,0xb2,0x20,0xb3,0x1d,0xb4,0x5d,0xb5,0xc1,0xb6,
0xe2,0xb7,0x6e,0xb8,0x0f,0xb9,0xed,0xba,0x90,0xbb,0xd4,
0xbc,0xd9,0xbd,0x42,0xbe,0xdd,0xbf,0x98,0xc0,0x57,0xc1,
0x37,0xc2,0x19,0xc3,0x78,0xc4,0x56,0xc5,0xaf,0xc6,0x74,
0xc7,0xd1,0xc8,0x04,0xc9,0x29,0xca,0x55,0xcb,0xe5,0xcc,
0x4c,0xcd,0xa0,0xce,0xf2,0xcf,0x89,0xd0,0xdb,0xd1,0xe4,
0xd2,0x38,0xd3,0x83,0xd4,0xea,0xd5,0x17,0xd6,0x07,0xd7,
0xdc,0xd8,0x8c,0xd9,0x8a,0xda,0xb4,0xdb,0x7b,0xdc,0xe9,
0xdd,0xff,0xde,0xeb,0xdf,0x15,0xe0,0x0d,0xe1,0x02,0xe2,
0xa2,0xe3,0xf3,0xe4,0x34,0xe5,0xcc,0xe6,0x18,0xe7,0xf8,
0xe8,0x13,0xe9,0x8d,0xea,0x7f,0xeb,0xae,0xec,0x21,0xed,
0xe3,0xee,0xcd,0xef,0x4d,0xf0,0x70,0xf1,0x53,0xf2,0xfd,
0xf3,0xab,0xf4,0x72,0xf5,0x64,0xf6,0x1c,0xf7,0x66,0xf8,
0xa9,0xf9,0xb0,0xfa,0x1e,0xfb,0xd7,0xfc,0xdf,0xfd,0x36,
0xfe,0x7d,0xff,0x31,0x47,0x43])

# Encrypted flag
encrypted = struct.pack ("37B", *[
0x27,0xb3,0x73,0x9d,0xf5,0x11,0xe7,0xb1,0xb3,0xbe,0x99,
0xb3,0xf9,0xf9,0xf4,0x30,0x1b,0x71,0x99,0x73,0x23,0x65,
0x99,0xb1,0x65,0x11,0x11,0xbe,0x23,0x99,0x27,0xf9,0x23,
0x99,0x05,0x65,0xce])

def get_tbl_entry(input_char):
    """ Simple translation function using the maybe_table for encryption """
    """ Logic reversed """
    counter = 0
    index = 0

    while counter < 0xfe:
        index = 2 * counter
        selected = maybe_table[index]

        # If our translated input == encrypted one then we have our char
        if selected == input_char:
            return maybe_table[index+1] # Fucking 1 shifting the table

        counter += 1
    return 0

def bruteforce():
    """ Ugly but works """
    result = ""
    for i in range(len(encrypted)):
        for x in range(127):
            entry = get_tbl_entry(x)

            if entry == encrypted[i]:
                result += chr(x)
                break
    print(result)

bruteforce()