Windows application using algorithm Rivest–Shamir–Adleman (RSA) cryptosystem, to create pairs, both public and private keys and encrypt or decrypt given text, using provided keys. Application has been written in C++ language, using .NET Framework and Visual Studio Express. More about RSA in Wikipedia.
I. Keys generation:
1. Find two prime numers (p,q).
2. Calculate (n): n = (pq).
3. Calculate Euler function for n: Ø = (p-1)(q-1).
4. Find (e) from: NWD(e,Ø) = 1, where 1 < e < n.
5. Find (d): d*e mod Ø = 1.
Public key (e,n)
Private key (d,n)
II. Text encryption:
1. Provide (e,n).
2. Change each letter to ASCII value.
3. Calculate value (z) of each letter: z = t^e mod n.
4. Print (z) value of each letter.
III. Text decryption:
1. Provide (d,n).
2. Read each value (values have to be separated by " ").
3. Calculate value (t): t = c^d mod n.
4. Print letter matching to ASCII value (t).
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Take what you want and have fun ;)