Add signing capability. (sign a word (last word?) using private key)
	so reciever can decrypt using my public key to verify the sender.

Add scrambling of padding to encrypted messages.
https://www.inf.pucrs.br/~calazans/graduate/TPVLSI_I/RSA-oaep_spec.pdf

Add cmd to list keys in keys dir and check if it has private key also.

Add use SHA-1 to provide public key finger print (hashing function).

Support reading file for encryption, decryption and maybe signing.

resources:
	https://crypto.stackexchange.com/questions/1448/definition-of-textbook-rsa
	https://crypto.stackexchange.com/questions/3608/why-is-padding-used-for-rsa-encryption-given-that-it-is-not-a-block-cipher
	https://www.inf.pucrs.br/~calazans/graduate/TPVLSI_I/RSA-oaep_spec.pdf