serpent

1. A reptile of the order Serpentes; a snake.
2. often Serpent
   1. In the Bible, the creature that tempted Eve.
   2. Satan.
3. A subtle, sly, or treacherous person.
4. A firework that writhes while burning.
5. Music. A deep-voiced wind instrument of serpentine shape, used principally from the 17th to 19th century, about 2.5 meters (8 feet) in length and made of brass or wood.
6. Serpent Serpens.

[Middle English, from Old French, from Latin serpēns, serpent-, from present participle of serpere, to creep.]

An obsolete wind instrument, originally a bass member of the Cornett family. It derives its name from its shape, a long, sinuous tube, roughly S-shaped with an extra twist and often supported with vertical struts. The tube, markedly conical, is just over 2 metres long. The smaller end holds a metal crook with a cup mouthpiece similar to that of a bass trombone but usually of ivory or horn. The body was made of wood and covered with leather or canvas and contained two sets of three holes, although 19th-century models sometimes had extra holes and keys to govern them. The serpent was invented c 1590 by a French churchman, Edmé Guillaume, for use in church music, particularly to double male voices in plainsong. It continued to be played in church bands in France and in England until the mid-19th century (Thomas Hardy mentioned it in this connection) but received a new lease of life in the mid-18th century by its adoption into military bands in Germany and England.

1. In Classical architecture, an emblem of healing, wisdom, and the Messenger (Hermes, St John, etc.), so part of the winged baton or caduceus.

2. Arranged in a circle, with tail in mouth, a serpent suggests immortality (see ouroboros).

The creature in the Book of Genesis that tempts Eve to eat the forbidden fruit, thus committing the first act of the Fall of Man. In the New Testament, the serpent of Genesis is identified with Satan.

See Snake.

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Serpent

Serpent's linear mixing stage
General
Designers	Ross Anderson, Eli Biham, Lars Knudsen
First published	1998-08-21
Derived from	Square
Certification	AES finalist
Cipher detail
Key sizes	128, 192 or 256 bits
Block sizes	128 bits
Structure	Substitution-permutation network
Rounds	32

Serpent is a symmetric key block cipher which was a finalist in the Advanced Encryption Standard (AES) contest, where it came second to Rijndael. Serpent was designed by Ross Anderson, Eli Biham, and Lars Knudsen.

Like other AES submissions, Serpent has a block size of 128 bits and supports a key size of 128, 192 or 256 bits^[1]. The cipher is a 32-round substitution-permutation network operating on a block of four 32-bit words. Each round applies one of eight 4-bit to 4-bit S-boxes 32 times in parallel. Serpent was designed so that all operations can be executed in parallel, using 32 1-bit slices. This maximizes parallelism, but also allows use of the extensive cryptanalysis work performed on DES.

Serpent was widely viewed as taking a more conservative approach to security than the other AES finalists, opting for a larger security margin: the designers deemed 16 rounds to be sufficient against known types of attack, but specified 32 rounds as insurance against future discoveries in cryptanalysis.

The Serpent cipher has not been patented. It is completely in the public domain and can be freely used by anyone. There are no restrictions or encumbrances whatsoever regarding its use. As a result, anyone is free to incorporate Serpent in their software (or hardware implementations) without paying license fees.

Contents 1 Rijndael vs. Serpent 2 Security 3 See also 4 Footnotes 5 External links

Rijndael vs. Serpent

Rijndael is a substitution-linear transformation network with ten, twelve, or fourteen rounds, depending on the key size, and with block sizes of 128 bits, 192 bits, or 256 bits, independently specified. Serpent is a substitution-linear transformation network which has thirty-two rounds, plus an initial and a final permutation to simplify an optimized implementation. The round function in Rijndael consists of three parts: a nonlinear layer, a linear mixing layer, and a key-mixing XOR layer. The round function in Serpent consists of key-mixing XOR, thirty-two parallel applications of the same 4x4 S-box, and a linear transformation, except in the last round, wherein another key-mixing XOR replaces the linear transformation. The nonlinear layer in Rijndael uses an 8x8 S-box whereas Serpent uses eight different 4x4 S-boxes. The 32 rounds make Serpent have a higher security margin than Rijndael; however, Rijndael with 10 rounds is faster and easier to implement for small blocks^{[citation needed]}. Hence, Rijndael was selected as the winner in the AES competition.

Security

The XSL attack, if effective, would weaken Serpent (though not as much as it would weaken Rijndael, which became AES). However, many cryptanalysts believe that once implementation considerations are taken into account the XSL attack would be more expensive than a brute force attack.

See also

• Tiger - hash function by the same authors.

Footnotes

1. ^ Serpent official site

External links

• Serpent homepage
• SCAN's entry for Serpent
• In Pellicano Case, Lessons in Wiretapping Skills - NYTimes May 5, 2008

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Dansk (Danish)
n. - slange

Nederlands (Dutch)
slang, heks

Français (French)
n. - serpent

Deutsch (German)
n. - Schlange, (Mus.) Serpent

Ελληνική (Greek)
n. - όφις, φίδι, (μουσ.) οφίαυλος

Italiano (Italian)
serpente

Português (Portuguese)
n. - serpente (f) (Zool.), serpente fig.

Русский (Russian)
змея, коварный предатель, злой, завистливый человек, серпент, шутиха, Змея (созвездие), змий-искуситель, дьявол

Español (Spanish)
n. - serpiente, culebra

Svenska (Swedish)
n. - orm

中文（简体）(Chinese (Simplified))
蛇, 狡猾的人, 蛇一般的人

中文（繁體）(Chinese (Traditional))
n. - 蛇, 狡猾的人, 蛇一般的人

한국어 (Korean)
n. - 뱀, 악마, (뱀처럼 꿈틀거리는) 불꽃 장치

日本語 (Japanese)
n. - ヘビ, 蛇のような人, 悪魔, 蛇座, セルパン, 蛇

العربيه (Arabic)
‏(الاسم) آله موسيقيه خشبيه قديمه, ألخداع, أفعى‏

עברית (Hebrew)
n. - ‮נחש, בוגדני, נוכל, שטן, רשע, כלי-הנשיפה בס בנוי מעץ מכוסה בעור, בצורת S‬

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