Editing ROT13 (section)

==Variants and combinations==
ROT5 is a practice similar to ROT13 that applies to numeric digits (0 to 9). ROT13 and ROT5 can be used together in the same message, sometimes called ROT18 (18 = 13 + 5) or ROT13.5.

ROT47 is a derivative of ROT13 which, in addition to scrambling the basic letters, treats numbers and common symbols. Instead of using the sequence <kbd>A–Z</kbd> as the alphabet, ROT47 uses a larger set of characters from the common [[character encoding]] known as [[ASCII]]. Specifically, the 7-bit printable characters, excluding space, from decimal 33 '<kbd>!</kbd>' through 126 '<kbd>~</kbd>', 94 in total, taken in the order of the numerical values of their ASCII codes, are rotated by 47 positions, without special consideration of case. For example, the character <kbd>A</kbd> is mapped to <kbd>p</kbd>, while <kbd>a</kbd> is mapped to <kbd>2</kbd>.

The use of a larger alphabet produces a more thorough obfuscation than that of ROT13; for example, a telephone number such as <kbd>+1-415-839-6885</kbd> is not obvious at first sight from the scrambled result <kbd>Z'\c`d\gbh\eggd</kbd>. On the other hand, because ROT47 introduces numbers and symbols into the mix without discrimination, it is more immediately obvious that the text has been encoded.

Example:
:<kbd>The Quick Brown Fox Jumps Over The Lazy Dog.</kbd>
enciphers to
:<kbd>%96 "F:4< qC@H? u@I yF>AD ~G6C %96 {2KJ s@8]</kbd>

The [[GNU C library]], a set of standard routines available for use in [[computer programming]], contains a [[function (programming)|function]]—'''<kbd>mem<abbr title=frobnicate>frob</abbr>()</kbd>'''<ref>{{Cite web|url=https://www.gnu.org/software/libc/manual/html_node/Obfuscating-Data.html|date=3 December 2006|title=5.13 Obfuscating Data|work=The GNU C Library Reference Manual|publisher=[[Free Software Foundation]]|access-date=2 August 2019|archive-date=2 August 2019|archive-url=https://web.archive.org/web/20190802141847/https://www.gnu.org/software/libc/manual/html_node/Obfuscating-Data.html|url-status=live}}</ref>—which has a similar purpose to ROT13, although it is intended for use with arbitrary binary data. The function operates by combining each [[byte]] with the [[Binary number|binary]] pattern 00101010 ([[42 (number)|42]]) using the [[exclusive or]] (XOR) operation. This effects a [[simple XOR cipher]]. Like ROT13, XOR (and therefore <kbd>memfrob()</kbd>) is self-reciprocal, and provides a similar, virtually absent, level of security.