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For example, computer processors are often designed to process data grouped into words of a given length of bits (8 bit, 16 bit, 32 bit, 64 bit, etc.). The bit length of each word defines, for one thing, how many memory locations can be independently addressed by the processor. In cryptography, the key size of an algorithm is the bit length of ...
In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits. It is a fast and simple action, basic to the higher-level arithmetic operations and directly supported by the processor. Most bitwise operations are presented as two-operand ...
The length of this bit string is the block size. [1] Both the input and output are the same length; the output cannot be shorter than the input – this follows logically from the pigeonhole principle and the fact that the cipher must be reversible – and it is undesirable for the output to be longer than the input.
Other commonly used names for this concept are prefix-free code, instantaneous code, or context-free code. The example mapping M 3 {\displaystyle M_{3}} above is not a prefix code because we do not know after reading the bit string "0" whether it encodes an "a" source symbol, or if it is the prefix of the encodings of the "b" or "c" symbols.
A variable-length quantity (VLQ) is a universal code that uses an arbitrary number of binary octets (eight-bit bytes) to represent an arbitrarily large integer. A VLQ is essentially a base-128 representation of an unsigned integer with the addition of the eighth bit to mark continuation of bytes. VLQ is identical to LEB128 except in endianness ...
The best-known is the string "From " (including trailing space) at the beginning of a line, used to separate mail messages in the mbox file format. By using a binary-to-text encoding on messages that are already plain text, then decoding on the other end, one can make such systems appear to be completely transparent .
The array L stores the length of the longest common suffix of the prefixes S[1..i] and T[1..j] which end at position i and j, respectively. The variable z is used to hold the length of the longest common substring found so far. The set ret is used to hold the set of strings which are of length z.
If n is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). Note that for variable-length encodings such as UTF-8 , UTF-16 or Shift-JIS , it can be necessary to remove string positions at the end, in order to avoid invalid strings.