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8: Block Cipher Modes of Operation

  • Page ID
    7389
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    One of the drawbacks of the previous CPA-secure encryption scheme is that its ciphertexts are \(\lambda\) bits longer than its plaintexts. In the common case that we are using a block cipher with blocklength blen \(=\lambda\), this means that ciphertexts are twice as long as plaintexts. Is there any way to encrypt data (especially lots of it) without requiring such a significant overhead?

    A block cipher mode refers to a way to use a block cipher to efficiently encrypt a large amount of data (more than a single block). In this chapter, we will see the most common modes for CPA-secure encryption of long plaintexts.


    This page titled 8: Block Cipher Modes of Operation is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Mike Rosulek (Open Oregon State) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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