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RivestShamirAdleman

50

 prob.txt

import gmpy

def root_e(c, e, n):

    bound = gmpy.root(n, e)[0]

    m = gmpy.root(c, e)[0]

    return m, bound

n = 22272129080562722886614022632205442705494455272860112814093083500097723366897651161029102178806468364810560145326674298943748926312059319333104024877629414355081997511170571841726554870330438449136414942769879449909945280622679982416961505259605748700527626064176345428348075666618966413358066674766244602120334405919054045097465042177827566762056612497539403392371174259602854649957161582616110665358774209954483243807893225011511670025850800717182535575577848500527430246259134071980979951803599863210705004134764027126983838884518704239682964897619030091789047630556807645411417077149617559860988186649846538955623

e = 3

c = 56274920108122478990888092521371739605513959053322262229138771723654033167756128122086229722406180593128664696512912311575327724724695863345048713415525599333

m, bound = root_e(c, e, n)

h = hex(m)[2:]

flag = ''

for i in range(0, len(h), 2):

    flag += chr(int(h[i:i+2], 16))

print(flag)

flag{nO_paDDing00_rsa}

です。

RSA暗号を可能にしたEulerの定理 [単行本（ソフトカバー）]

田中 隆幸

東京図書出版

2017-02-03

Shadow Cat

We only know that one used /etc/shadow file to encrypt important message for us. shadow.txt encrypted.txt

jr:x:17792:0:99999:7:::

z:x:17930:0:99999:7:::

a:x:17930:0:99999:7:::

x:x:17930:0:99999:7:::

q:x:17930:0:99999:7:::

l:x:17930:0:99999:7:::

v:x:17930:0:99999:7:::

e:x:17930:0:99999:7:::

f:x:17930:0:99999:7:::

b:x:17930:0:99999:7:::

r:x:17930:0:99999:7:::

g:x:17930:0:99999:7:::

n:x:17930:0:99999:7:::

o:x:17930:0:99999:7:::

p:x:17930:0:99999:7:::

s:x:17930:0:99999:7:::

c:x:17930:0:99999:7:::

w:x:17930:0:99999:7:::

d:x:17930:0:99999:7:::

t:x:17930:0:99999:7:::

h:x:17930:0:99999:7:::

m:x:17930:0:99999:7:::

k:x:17930:0:99999:7:::

i:x:17930:0:99999:7:::

y:x:17930:0:99999:7:::

j:x:17930:0:99999:7:::

u:x:17930:0:99999:7:::

underscore:x:17930:0:99999:7:::

$ unshadow passwd.txt shadow.txt > johnpasswd

$ john -wordlist=/usr/share/dict/words johnpasswd 

$ john --show johnpasswd 

jr:1:17792:0:99999:7:::

a:a:17930:0:99999:7:::

x:b:17930:0:99999:7:::

q:c:17930:0:99999:7:::

l:w:17930:0:99999:7:::

v:h:17930:0:99999:7:::

e:i:17930:0:99999:7:::

f:j:17930:0:99999:7:::

b:k:17930:0:99999:7:::

r:l:17930:0:99999:7:::

g:m:17930:0:99999:7:::

n:n:17930:0:99999:7:::

o:x:17930:0:99999:7:::

p:y:17930:0:99999:7:::

s:d:17930:0:99999:7:::

c:e:17930:0:99999:7:::

w:f:17930:0:99999:7:::

d:g:17930:0:99999:7:::

t:o:17930:0:99999:7:::

h:p:17930:0:99999:7:::

m:q:17930:0:99999:7:::

k:u:17930:0:99999:7:::

i:v:17930:0:99999:7:::

y:r:17930:0:99999:7:::

j:s:17930:0:99999:7:::

u:t:17930:0:99999:7:::

underscore:z:17930:0:99999:7:::

hajjzvajvzqyaqbendzvajvqauzarlapjzrkybjzenzuvczjvastlj

pass_hash_cracking_hashcat_always_lurks_in_the_shadows

VolgaCTF{pass_hash_cracking_hashcat_always_lurks_in_the_shadows}

です。

パスワード解析 完全版 [単行本（ソフトカバー）]

IPUSIRON

データ・ハウス

2010-06-03

cuz_rsa_is_lub

161

rsa.txt

Author: Akir4

def exgcd(m, n):

  if n>0:

    y,x,d = exgcd(n, m%n)

    return x, y-m/n*x, d

  else:

    return 1, 0, m

n = 71641831546926719303369645296528546480083425905458247405279061196214424558100678947996271179659761521775290973790597533683668081173314940392098256721488468660504161994357

e = 65537

c = 63127079832500412362950100242549738176318170072331491750802716138621322974529994914407846448954487685068331564008936808539420562251661435790855422130443584773306161128156

p = 8464149782874043593254414191179506861158311266932799636000173971661904149225893113311

q = 8464149782874043593254414191179506861158311266932799636000173971661904149225893113387

d = exgcd(e, (p-1)*(q-1))[0] % ((p-1)*(q-1))

s = pow(c, d, n)

h = format(s, 'x')

f = ''

for i in range(0, len(h), 2):

f += chr(int(h[i:i+2], 16))

print(f)

b00t2root{RSA_c4n_b3_vuln3r4bl3}

RSA暗号を可能にしたEulerの定理 [単行本（ソフトカバー）]

田中 隆幸

東京図書出版

2017-02-03

Count me in!

Points: 500

Solves: 1

I've been lately using this cool AES-CTR, but it was super slow, so I made a parallel version. Now it's blazing fast, but for some reason I have trouble decrypting the data...

count_me_in.tar.gz 2.2 KB

import multiprocessing

from Crypto.Cipher import AES

from secret import key, flag

counter = 0

aes = AES.new(key, AES.MODE_ECB)

def chunk(input_data, size):

    return [input_data[i:i + size] for i in range(0, len(input_data), size)]

def xor(*t):

    from functools import reduce

    from operator import xor

    return [reduce(xor, x, 0) for x in zip(*t)]

def xor_string(t1, t2):

    t1 = map(ord, t1)

    t2 = map(ord, t2)

    return "".join(map(chr, xor(t1, t2)))

def pad(data):

    pad_byte = 16 - len(data) % 16

    return data + (chr(pad_byte) * pad_byte)

def worker_function(block):

    global counter

    key_stream = aes.encrypt(pad(str(counter)))

    result = xor_string(block, key_stream)

    counter += 1

    return result

def distribute_work(worker, data_list, processes=8):

    pool = multiprocessing.Pool(processes=processes)

    result = pool.map(worker, data_list)

    pool.close()

    return result

def encrypt_parallel(plaintext, workers_number):

    chunks = chunk(pad(plaintext), 16)

    results = distribute_work(worker_function, chunks, workers_number)

    return "".join(results)

def main():

    plaintext = """The Song of the Count

You know that I am called the Count

Because I really love to count

I could sit and count all day

Sometimes I get carried away

I count slowly, slowly, slowly getting faster

Once I've started counting it's really hard to stop

Faster, faster. It is so exciting!

I could count forever, count until I drop

1! 2! 3! 4!

1-2-3-4, 1-2-3-4,

1-2, i love couning whatever the ammount haha!

1-2-3-4, heyyayayay heyayayay that's the sound of the count

I count the spiders on the wall...

I count the cobwebs in the hall...

I count the candles on the shelf...

When I'm alone, I count myself!

I count slowly, slowly, slowly getting faster

Once I've started counting it's really hard to stop

Faster, faster. It is so exciting!

I could count forever, count until I drop

1! 2! 3! 4!

1-2-3-4, 1-2-3-4, 1,

2 I love counting whatever the

ammount! 1-2-3-4 heyayayay heayayay 1-2-3-4

That's the song of the Count!

""" + flag

    encrypted = encrypt_parallel(plaintext, 32)

    print(encrypted.encode("hex"))

if __name__ == '__main__':

    multiprocessing.freeze_support()

    main()

9d5c66e65fae92af9c8a55d9d3bf640e

’The Song of the '

54686520536f6e67206f662074686520

c93403c60cc1fcc8bce533f9a7d7012e

import binascii

def xor(*t):

    from functools import reduce

    from operator import xor

    return [reduce(xor, x, 0) for x in zip(*t)]

def xor_string(t1, t2):

    t1 = map(ord, t1)

    t2 = map(ord, t2)

    return "".join(map(chr, xor(t1, t2)))

def decrypt(no):

encry = s[no*32:no*32+32]

plain = plaintext[no*16:no*16+16]

key_stream = xor_string(binascii.unhexlify(encry), plain)

for enc in l:

plain = xor_string(binascii.unhexlify(enc), key_stream)

print([plain])

plaintext = """The Song of the Count

You know that I am called the Count

Because I really love to count

I could sit and count all day

Sometimes I get carried away

I count slowly, slowly, slowly getting faster

Once I've started counting it's really hard to stop

Faster, faster. It is so exciting!

I could count forever, count until I drop

1! 2! 3! 4!

1-2-3-4, 1-2-3-4,

1-2, i love couning whatever the ammount haha!

1-2-3-4, heyyayayay heyayayay that's the sound of the count

I count the spiders on the wall...

I count the cobwebs in the hall...

I count the candles on the shelf...

When I'm alone, I count myself!

I count slowly, slowly, slowly getting faster

Once I've started counting it's really hard to stop

Faster, faster. It is so exciting!

I could count forever, count until I drop

1! 2! 3! 4!

1-2-3-4, 1-2-3-4, 1,

2 I love counting whatever the

ammount! 1-2-3-4 heyayayay heayayay 1-2-3-4

That's the song of the Count!

"""

f = open('output.txt')

s = f.read()

f.close()

l = [s[i: i+32] for i in range(0, len(s), 32)]

decrypt(0)

decrypt(10)

decrypt(20)

decrypt(30)

decrypt(39)

decrypt(49)

decrypt(54)

decrypt(55)

$ python bbb.py

['The Song of the ']

['Count\n\nYou know ']

['that I am called']

[' the Count\nBecau']

['se I really love']

[' to count\nI coul']

['d sit and count ']

['all day\nSometime']

['s I get carried ']

['away\nI count slo']

(略)

['wly, slowly, slo']

['wly getting fast']

["er\nOnce I've sta"]

['rted counting it']

["'s really hard t"]

['o stop\nFaster, f']

['aster. It is so ']

['exciting!\nI coul']

['d count forever,']

[' count until I d']

(略)

['rop\n1! 2! 3! 4!\n']

['1-2-3-4, 1-2-3-4']

[',\n1-2, i love co']

['uning whatever t']

['he ammount haha!']

['\n1-2-3-4, heyyay']

['ayay heyayayay t']

["hat's the sound "]

['of the count\nI c']

['ount the spiders']

(略)

[' on the wall...\n']

['I count the cobw']

['ebs in the hall.']

['..\nI count the c']

['andles on the sh']

["elf...\nWhen I'm "]

['alone, I count m']

['yself!\nI count s']

['lowly, slowly, s']

['\n\xa4\x17\x84\x1aDc\xd5\xbbN\x84\x05=q3_']

["ster\nOnce I've s"]

(略)

['lowly getting fa']

['\x15\xbf\x05\x9ai+j\xd3\xaa\x1a\xa4L,4uM']

['tarted counting ']

["it's really hard"]

[' to stop\nFaster,']

[' faster. It is s']

['o exciting!\nI co']

['uld count foreve']

['r, count until I']

[' drop\n1! 2! 3! 4']

['\x7f\xc8\xf6\xda\xdb\x8c4\x9f\xed\xf5\x12\x07\xb1\xb9\xac\xf2']

['-4, 1,\n2 I love ']

(略)

['!\n1-2-3-4, 1-2-3']

['s\xf6\xeb\xd7\xd8\x8d\r\x80\xf9\x90\x12Z\xf3\xfd\xe4\xe1']

['counting whateve']

['r the\nammount! 1']

['-2-3-4 heyayayay']

['^l\xebK\x13\x91\x97\xff\x94F\x80\xc0\xf7d\x16U']

['\xb2\xecR\xf0\x05*\x8ez\xe0{,|.\xf5\xde\xf6']

['g of the Count!\n']

(略)
[' heayayay 1-2-3-']

['\xcc\xe8\xdc\xdao\xda`\xe4\r\x1d\x9d\x91\xeb\xbc\xfb\x8e']

['\x19$\xe1LJ\x84\x86\xfb\xcd%\xde\x98\xab=\x04r']

['p4{at_the_end_of']

['_the_day_you_can']

(略)

["4\nThat's the son"]

['\xe1\xc6i\xfeD*\xc1l\xe0L+l`\xf2\x90\x92']

['\x88\xd6\xf3\xd3z\xf13\xffH6\x90\x9a\xaf\x90\xfb\x86']

['\xa7\x96\xe0\xd7Q\xca&\xeer\x10\x9a\x81\x94\xac\xf5\x8e']

['_only_count_on_y']

['ourself}\x08\x08\x08\x08\x08\x08\x08\x08']

p4{at_the_end_of_the_day_you_can_only_count_on_yourself}

です。

暗号技術の教科書 [単行本（ソフトカバー）]

吹田 智章

ラトルズ

2018-12-21

szabo: 1.000.000.000.000

babbage: 1.000.000

wei: 1

import binascii

a = b'333443335f6772616e646d615f626f756768745f736f6d655f626974636f696e'

print binascii.unhexlify(a)

34C3_grandma_bought_some_bitcoin

はじめてのブロックチェーン・アプリケーション Ethereumによるスマートコントラクト開発入門 (DEV Engineer's Books) [単行本（ソフトカバー）]

渡辺 篤

翔泳社

2017-08-03