Algorithms

Message recovery scheme

• Asymmetric encryption and decryption.

• Only for RSA.

Signing

$$A_x(doc) = info + E(K_x^{-1}, doc)$$

Verification

• $info$ -> $K_x$

• $D(K_x,A_x(doc))$

• Check the integrity of $doc$.

Message appendix scheme

• Digest functions.

• Asymmetric signature and validation.

• RSA, ElGamal (DSA), EC.

Signing

• $A_x(doc) = info + E(K_x^{-1}, h(doc+info))$

• $A_x(doc) = info + S(K_x^{-1}, h(doc+info))$

Verification

• $info$ -> $K_x$

• $D(K_x,A_x(doc)) \equiv h(doc + info)$

• $V(K_x,A_x(doc)), h(doc + info) = True$