Crypto U4, Block Cipher, Electronic Codebook Mode (ECB)

jjanesko
Note by , created almost 6 years ago

IYM002 (Unit 4 - Symmetric Crypto) Note on Crypto U4, Block Cipher, Electronic Codebook Mode (ECB), created by jjanesko on 02/04/2013.

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jjanesko
Created by jjanesko almost 6 years ago
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Encryption key used with encryption algorithm to encrypt each block of plaintext

Decryption key used with decryption algorithm to decrypt each block of plaintext

Problems Attacker could reorganize order of blocks of text without noticing. Attacker could replay old parts of message. Attacker could delete blocks of ciphertext without noticing. Attacker could repeated blocks without noticing. Attacker could mount dictionary attacks. Attacker could mount statistical attacks since the same key is used to encrypt multiple blocks. How could we improve it? increase the size of the plaintext bllocks and cipher alphabets (combat dictionary attacks) allow some plaintext letters to be encrypted to different ciphertext letters make the ciphertext encryption position dependent

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