some small fixes

CTFs_and_WarGames/2014-ASIS-CTF/crypto_paillier/answer_pallier.py

@@ -0,0 +1,93 @@
+#!/usr/bin/python
+
+__author__ = "bt3gl"
+__email__ = "bt3gl@gmail.com"
+
+import decimal
+import socket
+from constants import mod
+
+def print_hex(secret):
+
+    # cutting L in the end
+    a = hex(secret)[:-1]
+
+    # cutting the \x symbol
+    b = a[2:].decode('hex')
+
+    return b
+
+
+
+def convolution(e1, e2, m2, mod):
+
+    return (e1 * e2 )%(mod*mod)
+
+
+
+def nc_paillier(mod):
+
+    # create socket
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    s.connect((HOST, PORT))
+
+
+    # answer the initial question
+    s.recv(4096)
+    s.send(b'paillier')
+    s.recv(4096)
+    m = s.recv(4096)
+    m = (m.split(": ")[1]).split('\n')[0]
+    mdec = decimal.Decimal(m)
+
+
+    # encrypt 1
+    e = '1'
+    m2 = decimal.Decimal(e)
+    s.send(b'E')
+    s.recv(4096)
+    s.send(e)
+    e2 = s.recv(4096)
+    e2 = e2.split(": ")[1]
+    e2dec = decimal.Decimal(e2)
+
+
+
+    # convolute the enc messages
+    answer = convolution(mdec, e2dec, m2, mod)
+
+
+    # get the description from the answer
+    s.send(b'D')
+    s.recv(4096)
+    s.recv(4096)
+    s.send(str(answer))
+    md = s.recv(4096)
+    md = md.split(": ")[1].strip()
+
+
+
+    # get the flag, remember to add d(e(1)) = 1
+    secret = long(md) + 1
+    flag = print_hex(secret)
+    print("The flag is: ")
+    print flag
+
+
+
+
+
+if __name__ == "__main__":
+
+    # really long numbers
+    decimal.getcontext().prec = 1240
+
+    PORT = 12445
+    HOST = 'asis-ctf.ir'
+
+    nc_paillier(mod)
+
+
+
+
+

CTFs_and_WarGames/2014-ASIS-CTF/crypto_paillier/binary_search.py

@@ -0,0 +1,62 @@
+#!/usr/bin/python
+
+__author__ = "bt3gl"
+__email__ = "bt3gl@gmail.com"
+
+
+import decimal
+import socket
+
+
+
+
+def bs_paillier(lo, hi, s):
+    if hi < lo: return None
+    mid = (hi + lo) // 2
+    print("We are at: ")
+    print(mid)
+
+    s.send(b'E')
+    s.recv(4096)
+    s.send(str(mid)[:-1])
+    ans = s.recv(4096)
+
+    if 'None' in ans:
+        print "Found it!"
+        return mid + 1
+    elif 'Your secret' in ans:
+        return bs_paillier(lo, mid-1, s)
+    else:
+        return bs_paillier(mid+1, hi, s)
+
+
+
+
+def get_mod_paillier():
+
+    # create socket, answer first question
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    s.connect((HOST, PORT))
+    s.recv(4096)
+    s.send(b'paillier')
+    s.recv(4096)
+
+    # start binary search
+    hi = pow(11,307)
+    lo = pow(10,307)
+    mod = bs_paillier(lo, hi, s)
+    print mod
+
+
+
+if __name__ == "__main__":
+
+    PORT = 12445
+    HOST = 'asis-ctf.ir'
+
+    get_mod_paillier()
+
+
+
+
+

CTFs_and_WarGames/2014-ASIS-CTF/crypto_paillier/constants.py

@@ -0,0 +1,4 @@
+import decimal
+
+#mod = decimal.Decimal('28414252178421170251910042147689368446511995764529924640302525001150082023847807850723344018358163485930344707394699713532305322202216635189806057491940857063203918400016948903778913790645080815377317956510275921513980400357522675326929234601338948461475089468134681894547897715946279673410647104276477333937')
+mod = decimal.Decimal('17671943390317527594740575037779239788090749028363849573873871285525785364877468659238291287413782918855995881353189626069716161186805808731291508724925847487655603905895106750055611619881911787280882269077856999823769344599404478814635216943095238063240285592085964648122007040660676934950342692770738186633')

CTFs_and_WarGames/2014-ASIS-CTF/crypto_paillier/nc_paillier.py

@@ -0,0 +1,85 @@
+#!/usr/bin/python
+
+__author__ = "bt3gl"
+__email__ = "bt3gl@gmail.com"
+
+
+import decimal
+import socket
+
+
+def nc_paillier():
+
+    # create socket
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    s.connect((HOST, PORT))
+
+
+    # answer the initial question
+    print s.recv(4096)
+    s.send(b'paillier')
+
+
+    # get the secret
+    print s.recv(4096)
+    m = s.recv(4096)
+
+    # cleaning it
+    m = (m.split(": ")[1]).split('\n')[0]
+
+    # it's good to print (because it changes periodically)
+    print("The secret is: ")
+    print(m)
+
+    # change from str to long decimal
+    mdec = decimal.Decimal(m)
+
+
+    '''
+        From here you can do whatever you want.
+    '''
+    # If you want to encrypt messages
+
+    msg_to_e = '1'
+
+    s.send(b'E')
+    print s.recv(4096)
+    s.send(msg_to_e)
+    me = s.recv(4096)
+    me = me.split(": ")[1]
+
+    print("Secret for %s is:" %(msg_to_e))
+    print(me)
+
+    medec = decimal.Decimal(me)
+
+
+    # If you want to decrypt messages
+
+    msg_to_d = me
+
+    s.send(b'D')
+    s.recv(4096)
+    s.recv(4096)
+    s.send(msg_to_d)
+    md = s.recv(4096)
+    md = md.split(": ")[1].strip()
+
+    print("Decryption is: ")
+    print(md)
+
+    mddec = decimal.Decimal(md)
+
+
+
+
+
+if __name__ == "__main__":
+    # really long numbers
+    decimal.getcontext().prec = 1240
+
+    PORT = 12445
+    HOST = 'asis-ctf.ir'
+
+    nc_paillier()
+