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Unformatted text preview: CS-416 Social and Professional Issues in Computing Homework Assignment What is the most important difference between DES and AES? The most important difference is that DES is a Feistel network algorithm while AES is a substitution-permutation-network. An encryption algorithm which uses Feistel network to operate (DES) requires only a reversal of the key schedule to encrypt and decrypt data. On the other hand, a substitution-permutation network algorithm (AES) operates with a series of linked mathematical operations. The networks are formed using S-boxes and P-boxes that transform blocks of input bits into output bits. How does public-key cryptography work? Public-key cryptography uses two kinds of keys to operate. A public key that may be freely distributed and used by any party to encrypt data; this data is to be only viewed by the key owner. When the encrypted data is to be decrypted, the owner uses a private key to decrypt the data. The private key can not be derived from the public key, and the secrecy of the data depends on the secrecy of the private key. *Source: Wikipedia Public-Key Article What is the idea of key escrow, and what are some of the problems it would cause? A Key escrow is an arrangement or a policy in which the keys used for encryption and decryption of data is held by a third party (i.e Gov's Agencies) so that any encrypted data can be decrypted for the purpose of national security. One problem with the key escrow arrangement is due to the mistrust of the security of the escrow; a long history of the technical insecurity of private and public firms keeping data secret prevents the trust of a third party holding a cryptographic key. Another problem which prevented the success of the key escrow arrangement is law related. The third party must have a court order to allow them to decrypt the data; implementation of this important issue into the system of the key escrow has not met this requirement. ...
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This note was uploaded on 03/30/2008 for the course CS 416 taught by Professor Dr.fischer during the Fall '06 term at New Haven.
- Fall '06