-
Notifications
You must be signed in to change notification settings - Fork 0
/
rsaSign.py
108 lines (89 loc) · 3.33 KB
/
rsaSign.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
'''
---PROGRAM DESCRIPTION---
Digital signature scheme based on RSA
(encryption portion)
Creates a signature.txt file in same directory containing the public keys
(overwrites same file on subsequent executions with new generated keys)
---Possible Improvements---
-find a better way of generating large primes
-add support for different file types?
-abstract sign.txt data to make it not obvious in what they represent
-find ways of protecting against different attacks
(i.e. chosen plaintext, "blinded signature" scheme)
---Future Design Tips---
-primes p,q must be at least 512 bits (2**9)
-"p-1" and "q-1" should have large prime factors
-gcd(p-1, q-1) should not be too large
-modulo 'n' should be at least 1024 bits (2**10)
-private key 'd' shouldn't be smaller than n**(1/4)
-------------------------
'''
import sys, random, hashlib
BLOCK_SIZE = 4096
def sign(msg):
'''Creates signature.txt file and writes public keys to it
Args:
msg (str): location of file containing information
'''
hashInt = hashFile(msg)
primes = generatePrimes()
encryptedKey = generateSignKey(primes[0], primes[1])
n = primes[0] * primes[1]
encryptedMsg = pow(hashInt, int(encryptedKey), n)
f = open("sign.txt", 'w')
f.write(str(encryptedMsg))
f.write("\n")
f.write(str(n))
f.close()
### --------------------------------------------------------------------------
### helper functions
### --------------------------------------------------------------------------
def generateSignKey(p, q):
'''Returns a secret RSA based signing int key
Args:
p (int): first prime number
q (int): second prime number
'''
euler = (p-1)*(q-1)
k = 1
d = 1.1 # dummy INIT value
while not(d.is_integer()):
# NOTE: hardcoded public key e = 65537 (2**16+1)
e = 65537
d = ((k*euler)+1)/(e)
k += 1
return d
def generatePrimes():
'''Returns two random 3-digit primes as tuple (p, q)'''
primes = [101, 103, 107, 109, 113,
127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197,
199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281,
283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379,
383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463,
467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571,
577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659,
661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761,
769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863,
877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977,
983, 991, 997]
r1 = random.randint(0, 142)
r2 = random.randint(0, 142)
return(primes[r1], primes[r2])
def hashFile(file):
'''Returns hash (int) of a given file
Args:
file (str): location of file to be hashed
'''
file_hash = hashlib.sha256()
with open(file, 'rb') as f:
fb = f.read(BLOCK_SIZE)
while len(fb) > 0:
file_hash.update(fb)
fb = f.read(BLOCK_SIZE)
hexHash = file_hash.hexdigest()
return int(hexHash, 16)
if __name__ == "__main__":
if(len(sys.argv) != 2):
print("Usage: python3 rsaSign.py file")
exit(0)
sign(sys.argv[1])