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The propagating cipher block chaining [25] or plaintext cipher-block chaining [26] mode was designed to cause small changes in the ciphertext to propagate indefinitely when decrypting, as well as when encrypting. In PCBC mode, each block of plaintext is XORed with both the previous plaintext block and the previous ciphertext block before being ...
A book cipher is a cipher in which each word or letter in the plaintext of a message is replaced by some code that locates it in another text, the key. A simple version of such a cipher would use a specific book as the key, and would replace each word of the plaintext by a number that gives the position where that word occurs in that book.
A block cipher uses blocks as an unvarying transformation. Even a secure block cipher is suitable for the encryption of only a single block of data at a time, using a fixed key. A multitude of modes of operation have been designed to allow their repeated use in a secure way to achieve the security goals of confidentiality and authenticity.
OCB performance overhead is minimal compared to classical, non-authenticating modes like cipher block chaining. OCB requires one block cipher operation per block of encrypted and authenticated message, and one block cipher operation per block of associated data. There is also one extra block cipher operation required at the end of process.
Careful choice must be made in selecting the mode of operation of the cipher. The simplest mode encrypts and decrypts each 128-bit block separately. In this mode, called electronic code book (ECB), blocks that are identical will be encrypted identically; this is entirely insecure. It makes some of the plaintext structure visible in the ciphertext.
The United States National Security Agency documents sometimes use codebook to refer to block ciphers; compare their use of combiner-type algorithm to refer to stream ciphers. Codebooks come in two forms, one-part or two-part: In one-part codes, the plaintext words and phrases and the corresponding code words are in the same alphabetical order.
KHAZAD – 64-bit block designed by Barretto and Rijmen; Khufu and Khafre – 64-bit block ciphers; Kuznyechik – Russian 128-bit block cipher, defined in GOST R 34.12-2015 and RFC 7801. LION – block cypher built from stream cypher and hash function, by Ross Anderson; LOKI89/91 – 64-bit block ciphers; LOKI97 – 128-bit block cipher, AES ...
ICD-10 is the 10th revision of the International Classification of Diseases (ICD), a medical classification list by the World Health Organization (WHO). It contains codes for diseases, signs and symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or diseases. [1]