It security UE Past Papers Questions.

A message has 20 characters. If it is supposed to be encrypted using a block cipher of 64 bits, find the size of padding and number of blocks

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Using Simplified DES ( S-DES) algorithm to generate the first round key (K₁) and using that key to produce output of the first round ciphertext . Information in the appendix A can be useful in this question.

• Bits for key generation 1011100110
• Plaintext is 11110010

appendix A

P10 -- for key generation

P8 -- for key generation

Initial and final permutation -- for encryption

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• What is block size of a normal DES ?
• What is the cipher key size in DES ?
• What is the round- key size in DES ?

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Security is one of the main challenges which system developers face. The current system development methodologies do not provide enough evidence of integrating successifully security concerns throughout the whole range of development phases. The security concerns are based on five security goals of IT security. By using any software development methodology as refernce, show how you will incorporate the security concerns in your analysis, design, development , testing , evaluation and maintenance of a secure web based students information system for your university.

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