RSA Encryption Authentication

RSA Encryption Authentication

The RSA-encrypted nonces authentication method uses the RSA encryption public key cryptography algorithm. This technology requires that each party generate a pseudorandom number (a nonce) and encrypt it (and possibly other publicly and privately available information), using the other party’s RSA public key. Authentication occurs when each party decrypts the other party’s nonce with its local private key, and then uses the decrypted nonce to compute a keyed hash.

A drawback to this method is this: either side of the exchange can plausibly deny that it took part in the exchange. Cisco IOS software is the only Cisco product that supports this authentication method. Figure 9-20 shows an RSA encryption authentication exchange.

Figure 9-20: RSA encryption authentication exchange