proxies(文件)
【正文】 M) ? Sender transmits E on work ? Receiver extracts: M = decrypt(K, E) Public key encryption ? Previous scheme requires shared secret K ? If K is discovered, security is promised ? Public key encryption uses two keys: – Private key kept secret by user – Public key published by user ? To send to user, encrypt using public key, decrypt using private key PGP ? lio/1997/crypto/ Digital signatures ? Goal guarantee that message must have originated with certain entity ? Idea encrypt with private key, decrypt with public key ? Only owner of private key could have generated original message Packet filtering ? Can configure packet forwarding devices especially routers to drop certain packets ? Consider example: Packet filtering ? Suppose is test work and has controlling workstations ? Install filter to allow packets only from
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