# Tag Info

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What exactly does $0...0$ and $1...1$ mean usually? This simply means a (more or less) long string of $0$s or $1$s or more clearly $000000...000000$ and $111111...111111$. Related notiational notes, you may have to use soon: Sometimes the notation $0^n$ and $1^n$ is also used for these strings with exactly $n$ zeroes and ones. Even more generally ...

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Block size does not directly affect the security of the cipher. However, if block size is too small, it can prevent you from using the cipher securely. The main effect of block size is due to the fact that a block cipher is meant to be a pseudorandom permutation (PRP). That means that any two inputs will have outputs that differ iff the inputs differ. So ...

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Block ciphers are usually used in modes of operation. The security of a mode of operation depends on two things: the security of the underlying block cipher, and the security of the mode itself when you replace the block cipher with an "ideal" permutation. Say you're using a block cipher with block size $n$ bits, so with AES-256, $n = 128$ (the 256 refers ...

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It depends. (Usual answer to this kind of questions. We would need more details about the data damage to answer) XTS encryption mode is short for XEX-based tweaked-codebook mode with ciphertext stealing, and XEX stands for Xor-encrypt-xor. Let's look how the XEX mode is defined: (image from wikipedia) XTS definition changes only how the last block is ...

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