### 1.

Use the euler_phi()function in Sage to compute $$\phi(893\,456\,123)\text{.}$$

### 2.

Use the power_mod()function in Sage to compute $$7^{324}\pmod{895}\text{.}$$

### 3.

Explain the mathematical basis for saying: encrypting a message using an RSA public key is very simple computationally, while decrypting a communication without the private key is very hard computationally.

### 4.

Explain how in RSA message encoding differs from message verification.

### 5.

Explain how one could be justified in saying that Diffie and Hellman's proposal in 1976 was “revolutionary.”