Page 258 - CISSO_Prep_ Guide

• Secure message format – encrypt
with receiver's public.

• Open message format – encrypt with
sender's private (to authenticate
sender).

• Secure and signed message format –
encrypt with the sender's private than
with receiver's public (remember the
order). Think soft center with a hard,
crunchy shell.

• Strengths: confidentiality, access control,
authentication, integrity, non-repudiation.
• Weaknesses: computationally intense, slow.
• Public Key / Asymmetric approaches:
• Prime factoring
▪ RSA: 512, 768, 1024 bit keys.
Encrypts & provides digital
signatures for non-repudiation.
• Discrete logarithms.
▪ Diffie-Hellman (DH): only used
for key exchange.
▪ Elliptic Curve Cryptosystems
(ECC): algebraic points on an
elliptic curve. Faster and has
smaller key sizes.
▪ Digital Signature Standard
(DSS).