Cryptographic functions which transform plaintext into ciphertext or the other way around.

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Reordering non-block-aligned parts with DES in ECB mode

I was given a ciphertext file which was encrypted using DES in ECB mode. It is known that the plainttext that was encrypted has the following form: Each line of text consists of a payroll followed ...
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How we transfer 128bits cipher to a 4x4 matrix for AES input?

Why the input cipher for AES encryption, can write in 4x4 matrix with 8 bits entires, and can said is 128bits? if each cell is 8bits in binary, how we said this matrix is represent 128bits?
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Index of coincidence for completely random text over k alphabets

I'm confused about /Friedman's method 2 (using a table with column of k size of key, and n/k rows, n is the total size for cipher text) \begin{equation} m = ...
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Question on mono-alphabetic substitution cipher and poly-alphabetic substitution cipher

You know that a meaningful plaintext in a language with a 26-letter alphabet, like English, is encrypted using either the mono-alphabetic substitution cipher or the poly-alphabetic substitution cipher ...
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Decryption returns different data

I am new to cryptography so forgive me if I am doing anything stupid. I am following the Cryptography in JAVA book. I am creating my own kerberos. I am stuck at a point. I have Message class which ...