16.5. RSA Public Key Cryptosystem

Try these first

1. 1.

   What is the purpose of the public key in RSA?

   Hint

   Think about how messages are sent securely.

2. 2.

   Can anyone see the private key?

   Hint

   Who has access to decrypt the messages?

3. 3.

   What is required for the public key in RSA?

   • Primes only
   • A modulus and an exponent
   • Just a prime number

   Hint

   Think about what is involved in the encryption process.

4. 4.

   True or False: The private key can be shared with anyone who wants to send you a message.

   • True
   • False

   Hint

   Consider who should access the decryption capabilities.

5. 5.

   Given small primes p = 37 and q = 47, compute the values for N, φ(N), and suggest values for e and d.

   Hint

   Confirm that e is less than φ(N) and coprime.

6. 6.

   For N = 3233, compute the decryption of c = 2790 assuming d is known.

   Hint

   Follow the decryption formula correctly.