Editing Tiger (hash function) (section)

==Cryptanalysis==
Unlike MD5 or SHA-0/1, there are no known effective attacks on the full 24-round Tiger<ref name="reduced-round"/> except for pseudo-near collision.<ref>{{Cite conference
 | first1 = Florian
 | last1 = Mendel
 | first2 = Rijmen
 | last2 = Vincent
 | title = Cryptanalysis of the Tiger Hash Function
 | book-title = ASIACRYPT 2007
 | pages = 536–550
 | publisher = Springer Berlin / Heidelberg
 | doi = 10.1007/978-3-540-76900-2_33| doi-access = free
 }}</ref> While MD5 processes its state with 64 simple 32-bit operations per 512-bit block and SHA-1 with 80, Tiger updates its state with a total of 144 such operations per 512-bit block, additionally strengthened by large S-box look-ups.

[[John Kelsey (cryptanalyst)|John Kelsey]] and [[Stefan Lucks]] have found a collision-finding attack on 16-round Tiger with a time complexity equivalent to about 2<sup>44</sup> compression function invocations and another attack that finds pseudo-near collisions in 20-round Tiger with work less than that of 2<sup>48</sup> compression function invocations.<ref name="reduced-round">{{cite journal
| url=http://th.informatik.uni-mannheim.de/People/Lucks/papers/Tiger_FSE_v10.pdf
| title=Collisions and Near-Collisions for Reduced-Round Tiger
|author1=John Kelsey |author2=Stefan Lucks
| journal=Fast Software Encryption 13
| location=[[Graz]]
| year=2006
| archive-url=https://web.archive.org/web/20160304042512/http://th.informatik.uni-mannheim.de/People/Lucks/papers/Tiger_FSE_v10.pdf
| archive-date=2016-03-04
}}</ref> Florian Mendel et al. have improved upon these attacks by describing a collision attack spanning 19 rounds of Tiger, and a 22-round pseudo-near-collision attack. These attacks require a work effort equivalent to about 2<sup>62</sup> and 2<sup>44</sup> evaluations of the Tiger compression function, respectively.<ref>{{cite journal
| url=https://online.tugraz.at/tug_online/voe_main2.getvolltext?pCurrPk=20716
| title=Update on Tiger
|author=Florian Mendel |author2=Bart Preneel |author3=Vincent Rijmen |author4=Hirotaka Yoshida |author5=Dai Watanabe
| journal=Indocrypt 7
| location=[[Kolkata]]
| format=PDF
| year=2006}}</ref>