Documents/research/cryptography/Untitled.ipynb

RSA-notebook.ipynb

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      "source": "# RSA algorithm implementation in python\n<hr>"
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      "source": "from math import sqrt\nfrom random import *\n\n#check if the number is  prime or not\ndef is_miller_rabin_prime(n, k=10):\n    if n == 2:\n        return True\n    if not n & 1:\n        return False\n\n    def check(a, s, d, n):\n        x = pow(a, d, n)\n        if x == 1:\n            return True\n        for i in xrange(s - 1):\n            if x == n - 1:\n                return True\n            x = pow(x, 2, n)\n        return x == n - 1\n\n    s = 0\n    d = n - 1\n\n    while d % 2 == 0:\n        d >>= 1\n        s += 1\n\n    for i in xrange(k):\n        a = randrange(2, n - 1)\n        if not check(a, s, d, n):\n            return False\n    return True\n\n\n\n# ///////////////////////////////////////////\n#generate private key from e and phi\ndef generate_d(e, phi):\n    d = 0\n    x1 = 0\n    x2 = 1\n    y1 = 1\n    temp_phi = phi\n\n    while e > 0:\n        temp1 = temp_phi/e\n        temp2 = temp_phi - temp1 * e\n        temp_phi = e\n        e = temp2\n\n        x = x2- temp1* x1\n        y = d - temp1 * y1\n\n        x2 = x1\n        x1 = x\n        d = y1\n        y1 = y\n\n    if temp_phi == 1:\n        return d + phi\n\n# ////////// get next prime number ////////////\ndef get_nxt_prm(low_lim = 100000000000000000, up_lim = 100000000000000000000000):\n    n = randrange(low_lim, up_lim )\n\n    if is_miller_rabin_prime(n) == True:\n        return n\n    while is_miller_rabin_prime(n) == False:\n        n += 1\n\n    return n\n\n#///////////////////////////////////////////\n\ndef encrypt(pub_key, n, plaintext):\n    #Unpack the key into it's components\n\n    cipher = []\n\n    for c in plaintext:\n        assci_val = ord(c)\n        tmp_cipher = pow(assci_val, pub_key, n)\n        cipher.append(tmp_cipher)\n\n\n    return cipher\n\n\ndef decrypt(priv_key, n, ciphertext):\n    text = []\n    for t in ciphertext:\n        tmp_text = pow(t,priv_key, n)\n        tmp_c = chr (tmp_text)\n        text.append(tmp_c)\n    return text\n#///////////////////////////////////////////\n\ndef my_pow(a, e):\n    mul = 1\n    for i in range(1,e):\n        mul *= a\n\n    return mul\n\n##################################################################\n##################################################################\n\n\nPRIME_LOW_LIM = 10**6\nPRIME_UP_LIM = 100**9\n\np =  get_nxt_prm(PRIME_LOW_LIM, PRIME_UP_LIM)\nq = get_nxt_prm(PRIME_LOW_LIM, PRIME_UP_LIM )\nprint 'generating two prime number ...\\np = ', p, '\\nq = ', q, '\\n'\n\n\nn = p * q\nprint 'calculating (p*q)...\\n n =>', n\n\nphi = (p-1) * (q-1)\nprint '\\ncalculating (p-1)*(q-1)...\\n phi => ', phi, '\\n'\n\ne = get_nxt_prm(2, phi)\nprint '\\ngenerating public key ...\\n e => ', e , ' and length = ', len(str(e))\n\n\nd = generate_d(e, phi)\n\n\n\nprint  '\\ngenerating private key ...\\n d => ', d, '; length = ', len(str(d))\n\n#msg = 123\n#print 'Original message', msg\n\n#encrip_msg = pow(msg,e,n)\n#print 'encrypted message: ', encrip_msg\n\n#ttt = pow(msg, e, n)\n#decryp_msg = pow(encrip_msg, d, n)\n#print 'decrypted message: ', decryp_msg\n\nsecret_msg = 'hello how are you'\nprint '\\n\\nOrginal Message: ',secret_msg\n\nprint '\\nEncrypted message: '\naaaa =  encrypt(e, n, secret_msg)\nfor a in aaaa:\n    print a,\n\n\nprint '\\n\\nDecrypted message: '\nbbbb = decrypt(d,n, aaaa)\nfor b in bbbb:\n    print b,\n",
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          "text": "generating two prime number ...\np =  786709258744600993 \nq =  491849468931253789 \n\ncalculating (p*q)...\n n => 386942531116832324326612782024412477\n\ncalculating (p-1)*(q-1)...\n phi =>  386942531116832323048054054348557696 \n\n\ngenerating public key ...\n e =>  121327031582590434470174630011335053  and length =  36\n\ngenerating private key ...\n d =>  561698314797619019238914984058775109 ; length =  36\n\n\nOrginal Message:  hello how are you\n\nEncrypted message: \n14455771632145545850173578267156838 68895843678156386295559241558762639 192733712786940919027828192705696538 192733712786940919027828192705696538 119970030015389214863981240712568988 85899282463559380982929001086032931 14455771632145545850173578267156838 119970030015389214863981240712568988 192269082242455792120532725711217567 85899282463559380982929001086032931 243954766336442801710375055839269382 45384817009482099843900877556762664 68895843678156386295559241558762639 85899282463559380982929001086032931 102074773659448332761057499210785635 119970030015389214863981240712568988 44644789665370318448880445320218878 \n\nDecrypted message: \nh e l l o   h o w   a r e   y o u\n",
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      "source": "## Reference: \n\nhttps://simple.wikipedia.org/wiki/RSA_(algorithm)  \nhttp://stackoverflow.com/questions/17298130/working-with-large-primes-in-python\n  https://gist.github.com/JonCooperWorks/5314103#file-rsa-py-L92"
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