[codegate2016] compress 복호화

삽질은 삽질로써 의미가 있다.

 

4byte 먼저 돌리고, 2byte씩 돌리는 방식

하지만, 동일한 값이 중간에 나오므로 이상한 문자가 나오면 따로 분리하여 결과물을 확인 해야함.

 

import hashlib
import string

def encode(input_string):
    h = hashlib.md5(input_string[:4]).hexdigest()
    table = {
        'a': 1,
        'b': 2,
        'c': 3,
        'd': 4,
        'e': 5,
        'f': 6,
        'g': 7,
        'h': 8,
        'i': 9,
        'j': 0
    }
    out = ""
    prev = ""
    stage1 = []
    stage2 = []
    stage3 = ""
    passbyte = -1

    for ch in input_string:
        if ch in table.keys():
            stage1.append(table[ch])
        else:
            stage1.append(ch)

    for index, ch in enumerate(stage1):
        if len(stage1) <= index+1:
            if index != passbyte:
                stage2.append(ch)
            break

        if passbyte != -1 and passbyte == index:
            continue

        if type(ch) == int and type(stage1[index+1])==int:
            tmp = ch << 4
            tmp |= stage1[index+1]
            stage2.append(tmp)
            passbyte = index+1
        else:
            stage2.append(ch)

    for ch in stage2:
        if type(ch) == int:
            stage3 += chr(ch)
        else:
            stage3 += ch

    for index, ch in enumerate(stage3):
        if index >= len(h):
            choice = 0
        else:
            choice = index

        out += chr(ord(ch) ^ ord(h[choice]))

    encoded = "~u/"
    if out == encoded[0:len(out)]:
        print "[%s] match" % input_string
        return True

def main():
    for index in string.ascii_letters:
        for index1 in string.ascii_letters:
            for index2 in string.ascii_letters:
                for index3 in string.ascii_letters:
                    encode(index+index1+index2+index3)
if __name__ == "__main__" :
    main() 

E:\Temp>python codegate_compress_v.0.1.py
[dhdj] match
[diad] match
[FLag] match
[MAaf] match

 

 

import hashlib
import string

def encode(input_string):
    h = hashlib.md5(input_string[:4]).hexdigest()
    table = {
        'a': 1,
        'b': 2,
        'c': 3,
        'd': 4,
        'e': 5,
        'f': 6,
        'g': 7,
        'h': 8,
        'i': 9,
        'j': 0
    }
    out = ""
    prev = ""
    stage1 = []
    stage2 = []
    stage3 = ""
    passbyte = -1

    for ch in input_string:
        if ch in table.keys():
            stage1.append(table[ch])
        else:
            stage1.append(ch)

    for index, ch in enumerate(stage1):
        if len(stage1) <= index+1:
            if index != passbyte:
                stage2.append(ch)
            break

        if passbyte != -1 and passbyte == index:
            continue

        if type(ch) == int and type(stage1[index+1])==int:
            tmp = ch << 4
            tmp |= stage1[index+1]
            stage2.append(tmp)
            passbyte = index+1
        else:
            stage2.append(ch)

    for ch in stage2:
        if type(ch) == int:
            stage3 += chr(ch)
        else:
            stage3 += ch

    for index, ch in enumerate(stage3):
        if index >= len(h):
            choice = 0
        else:
            choice = index

        out += chr(ord(ch) ^ ord(h[choice]))

    encoded = "~u/\x15mK\x11N`[^\x13E2JKj0K;3^D3\x18\x15g\xbc\\Gb\x14T\x19E"
    if out == encoded[0:len(out)]:
        print "[%s] match" % input_string
        return True

def main():
    #org = "FLag is {compress_is_always_helpful!}"
    input_str = "FLag"
    encoded = "~u/\x15mK\x11N`[^\x13E2JKj0K;3^D3\x18\x15g\xbc\\Gb\x14T\x19E"
    count = 4
    print "string : %s" % input_str

    while count < len(encoded):
        for index in string.printable:
            if encode(input_str+index) == True:
                input_str += index
                break

        count += 1

if __name__ == "__main__" :
    main()

E:\Temp>python codegate_compress_v.0.1.py
string : FLag
[FLag ] match
[FLag i] match
[FLag is] match
[FLag is ] match
[FLag is {] match
[FLag is {c] match
[FLag is {co] match
[FLag is {com] match
[FLag is {comp] match
[FLag is {compr] match
[FLag is {compre] match
[FLag is {compres] match
[FLag is {compress] match
[FLag is {compress_] match
[FLag is {compress_i] match
[FLag is {compress_is] match
[FLag is {compress_is_] match
[FLag is {compress_is_a] match
[FLag is {compress_is_al] match
[FLag is {compress_is_alw] match
[FLag is {compress_is_alwa] match
[FLag is {compress_is_alway] match

 

import hashlib
import string


def encode(input_string):
    h = hashlib.md5(input_string[:4]).hexdigest()
    #str = "GDKggZ*!wX8"
    #h = hashlib.md5(str[:4]).hexdigest()
    table = {
        'a': 1,
        'b': 2,
        'c': 3,
        'd': 4,
        'e': 5,
        'f': 6,
        'g': 7,
        'h': 8,
        'i': 9,
        'j': 0
    }
    out = ""
    prev = ""
    stage1 = []
    stage2 = []
    stage3 = ""
    passbyte = -1

    for ch in input_string:
        if ch in table.keys():
            stage1.append(table[ch])
        else:
            stage1.append(ch)

    for index, ch in enumerate(stage1):
        if len(stage1) <= index+1:
            if index != passbyte:
                stage2.append(ch)
            break

        if passbyte != -1 and passbyte == index:
            continue

        if type(ch) == int and type(stage1[index+1])==int:
            tmp = ch << 4
            tmp |= stage1[index+1]
            stage2.append(tmp)
            passbyte = index+1
        else:
            stage2.append(ch)

    for ch in stage2:
        if type(ch) == int:
            stage3 += chr(ch)
        else:
            stage3 += ch

    for index, ch in enumerate(stage3):
        if index >= len(h):
            choice = 0
        else:
            choice = index

        out += chr(ord(ch) ^ ord(h[choice]))

    #if out == "~u/\x15mK\x11N`[^\x13E2JKj0K;3^D3\x18\x15g\xbc":
    if out == "~u/\x15mK\x11N`[^\x13E2JKj0K;3^D3\x18\x15g\xbc\\Gb\x14T\x19E"[0:len(out)]:
        print "[%s] match" % input_string
        print "encode count : %d" % len(out)
        return True

encoded = "~u/\x15mK\x11N`[^\x13E2JKj0K;3^D3\x18\x15g\xbc\\Gb\x14T\x19E"
input_str = "FLag is {compress_is_always_"
loop = len(input_str)

while loop < len(encoded):
    for index in string.printable:
        for index1 in string.printable:
            if encode(input_str+index+index1) == True:
                input_str += index+index1
    loop += 2

print "decode string length : %d" % loop
print "encode string length : %d" % len(encoded)

E:\Temp>python _codegate_compress.py
[FLag is {compress_is_always_he] match
encode count : 28
[FLag is {compress_is_always_help] match
encode count : 30
[FLag is {compress_is_always_helpfu] match
encode count : 32
[FLag is {compress_is_always_helpful!] match
encode count : 34