Imagine that two standards committees propose to save bandwidth by combining compression (such as the Lempel-Ziv algorithm used in the zip program) with encryption. Both committees are planning to use the one-time pad (with variable key length – meaning that the length of the used key will match the length of the plaintext to be encrypted). One committee proposes to compress messages before encrypting them. Explain why this may cause a security problem. The other committee proposes to compress ciphertexts. Explain why this is a bad idea.
Added by Edward H.
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Compression before encryption: If the message is compressed before encryption, it may cause a security problem because the compressed message may reveal some information about the original message. Compression algorithms work by finding patterns in the data and Show more…
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