Chapter 8: Security in Computer Networks
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Authorization
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passwords
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encrypted passwords
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nonces
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Encryption
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symmetric key
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same key used for both encryption and decryption
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fast algorithms, good for secret connections
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one-time keys can be obtained from a key distribution
center
DES, AES, for example
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public key
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different keys used for encryption and decryption
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public key is known to all, private key is only known
to the owner
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slower algorithms
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for secret communication, sender encrypts with the
receivers public key
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for digital signatures, signer uses their own private key
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typically, message digests are signed rather than the
entire message
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RSA, for example
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Message digest algorithms
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Firewalls
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packet filtering
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application gateways
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Attacks
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packet sniffing
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spoofing
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denial of service
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hijacking