- Generate Private Key Rsa Euclidean Code 2
- Generate Private Key Rsa Euclidean Code Examples
- Generate Private Key Rsa Euclidean Code 1
Jan 23, 2015 Agrahams lib supports RSA but it is very difficult to match it to the server-side (different reasons like: SSL has to be buyed from your hoster, many functions like OpenSSL or other RSA solutions can't be used, etc.) I'm almost there, except my ability to get this into code (I did not find good sources).
| #!/usr/bin/env python |
| # This example demonstrates RSA public-key cryptography in an |
| # easy-to-follow manner. It works on integers alone, and uses much smaller numbers |
| # for the sake of clarity. |
| ##################################################################### |
| # First we pick our primes. These will determine our keys. |
| ##################################################################### |
| # Pick P,Q,and E such that: |
| # 1: P and Q are prime; picked at random. |
| # 2: 1 < E < (P-1)*(Q-1) and E is co-prime with (P-1)*(Q-1) |
| P=97# First prime |
| Q=83# Second prime |
| E=53# usually a constant; 0x10001 is common, prime is best |
| ##################################################################### |
| # Next, some functions we'll need in a moment: |
| ##################################################################### |
| # Note on what these operators do: |
| # % is the modulus (remainder) operator: 10 % 3 is 1 |
| # // is integer (round-down) division: 10 // 3 is 3 |
| # ** is exponent (2**3 is 2 to the 3rd power) |
| # Brute-force (i.e. try every possibility) primality test. |
| defisPrime(x): |
| ifx%20andx>2: returnFalse# False for all even numbers |
| i=3# we don't divide by 1 or 2 |
| sqrt=x**.5 |
| whilei<sqrt: |
| ifx%i0: returnFalse |
| i+=2 |
| returnTrue |
| # Part of find_inverse below |
| # See: http://en.wikipedia.org/wiki/Extended_Euclidean_algorithm |
| defeea(a,b): |
| ifb0:return (1,0) |
| (q,r) = (a//b,a%b) |
| (s,t) =eea(b,r) |
| return (t, s-(q*t) ) |
| # Find the multiplicative inverse of x (mod y) |
| # see: http://en.wikipedia.org/wiki/Modular_multiplicative_inverse |
| deffind_inverse(x,y): |
| inv=eea(x,y)[0] |
| ifinv<1: inv+=y#we only want positive values |
| returninv |
| ##################################################################### |
| # Make sure the numbers we picked above are valid. |
| ##################################################################### |
| ifnotisPrime(P): raiseException('P (%i) is not prime'% (P,)) |
| ifnotisPrime(Q): raiseException('Q (%i) is not prime'% (Q,)) |
| T=(P-1)*(Q-1) # Euler's totient (intermediate result) |
| # Assuming E is prime, we just have to check against T |
| ifE<1orE>T: raiseException('E must be > 1 and < T') |
| ifT%E0: raiseException('E is not coprime with T') |
| ##################################################################### |
| # Now that we've validated our random numbers, we derive our keys. |
| ##################################################################### |
| # Product of P and Q is our modulus; the part determines as the 'key size'. |
| MOD=P*Q |
| # Private exponent is inverse of public exponent with respect to (mod T) |
| D=find_inverse(E,T) |
| # The modulus is always needed, while either E or D is the exponent, depending on |
| # which key we're using. D is much harder for an adversary to derive, so we call |
| # that one the 'private' key. |
| print'public key: (MOD: %i, E: %i)'% (MOD,E) |
| print'private key: (MOD: %i, D: %i)'% (MOD,D) |
| # Note that P, Q, and T can now be discarded, but they're usually |
| # kept around so that a more efficient encryption algorithm can be used. |
| # http://en.wikipedia.org/wiki/RSA#Using_the_Chinese_remainder_algorithm |
| ##################################################################### |
| # We have our keys, let's do some encryption |
| ##################################################################### |
| # Here I only focus on whether you're applying the private key or |
| # applying the public key, since either one will reverse the other. |
| importsys |
| print'Enter '>NUMBER' to apply private key and '<NUMBER' to apply public key; 'Q' to quit.' |
| whileTrue: |
| sys.stdout.write('? ') |
| line=sys.stdin.readline().strip() |
| ifnotline: break |
| ifline'q'orline'Q': break |
| ifline[0]'<': key=E |
| elifline[0]'>': key=D |
| else: |
| print'Must start with either < or >' |
| print'Enter '>NUMBER' to apply private key and '<NUMBER' to apply public key; 'Q' to quit.' |
| continue |
| line=line[1:] |
| try: before=int(line) |
| exceptValueError: |
| print'not a number: '%s''% (line) |
| print'Enter '>NUMBER' to apply private key and '<NUMBER' to apply public key; 'Q' to quit.' |
| continue |
| ifbefore>=MOD: |
| print'Only values up to %i can be encoded with this key (choose bigger primes next time)'% (MOD,) |
| continue |
| # Note that the pow() built-in does modulo exponentation. That's handy, since it saves us having to |
| # implement that ablity. |
| # http://en.wikipedia.org/wiki/Modular_exponentiation |
| after=pow(before,key,MOD) #encrypt/decrypt using this ONE command. Surprisingly simple. |
| ifkeyD: print'PRIVATE(%i) >> %i'%(before,after) |
| else: print'PUBLIC(%i) >> %i'%(before,after) |
// See Global Unlock Sample for sample code. CkRsa rsa; // Generate a 1024-bit key. Chilkat RSA supports // key sizes ranging from 512 bits to 4096 bits. // Note: Starting in Chilkat v9.5.0.49, RSA key sizes can be up to 8192 bits. // It takes a considerable amount of time and processing power to generate // an 8192-bit key. Bool success = rsa. Pseudo code is fine, but if I get actual code I won't be able to learn without plagiarism on my assignment which is a big no-no). As always, any help is genuinely appreciated. Thanks everyone! (And yes, I have seen these:RSA: Private key calculation with Extended Euclidean Algorithm and In RSA encryption, how do I find d, given p, q, e and c?). RSA encryption and decryption in Python (3) I need help using RSA encryption and decryption in Python. I am creating a private/public key pair, encrypting a message with keys and writing message to a file. Then I am reading ciphertext from file and decrypting text using key. Generating Keys for Encryption and Decryption.; 3 minutes to read +7; In this article. Creating and managing keys is an important part of the cryptographic process. Symmetric algorithms require the creation of a key and an initialization vector (IV). The key must be kept secret from anyone who should not decrypt your data. Security Assignment, Implementing 128-bit RSA with prime number and extended Euclidean calculations. In this assignment, you are required to write a program in C/ JAVA( any programming language) to implement the RSA algorithm. Requirements: Generate two large random numbers (128bits) Test if the number generated is prime number.
commented Mar 1, 2017
Generate Private Key Rsa Euclidean Code 2
Perfect explanation! Thanks for your answer to «Is there a simple example of an Asymmetric encryption/decryption routine?» I was looking for this kind of routine to encrypt numbers inferiors to 1 billion with results inferiors to 1 billion. (I'm limited in string length). Is this routine safe for that task? Can we computed (by brute force?) the private key from and only the public key and the modulus? |
commented Feb 6, 2018
Generate Private Key Rsa Euclidean Code Examples
The condition to have an inverse in line 63 is wrong ! |