Question on Password Encryption, using stdlib or third party lib

[0xFFFFFFFF]

On a project I was asked to

a- Compute SHA-256 of a password
b- Do a BigInteger, convert to Hex String
c- Encrypt the key using a public key with the following 
parameters
   Entropy: I'm given some numbers
   Modulus: also given long numbers

[encrypt using RSA algorithm]

So far I'm familiar with a and b in Dlang.

how do I go about c) In Dlang ?

Thanks