Paper 2, Section II, G
Briefly describe the public key cipher.
Just before it went into liquidation, the Internet Bank decided that it wanted to communicate with each of its customers using an RSA cipher. So, it chose a large modulus , which is the product of two large prime numbers, and chose encrypting exponents and decrypting exponents for each customer . The bank published and and sent the decrypting exponent secretly to customer . Show explicitly that the cipher can be broken by each customer.
The bank sent out the same message to each customer. I am not a customer of the bank but have two friends who are and I notice that their published encrypting exponents are coprime. Explain how I can find the original message. Can I break the cipher?