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Sha Is Perhaps the Most Widely Used Family of Hash Functions.

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Cryptographic hash function

Secure Hash Algorithms
Concepts
hash functions· SHA· DSA
Main standards
SHA-0· SHA-1· SHA-2· SHA-iii
  • v
  • t
  • e
SHA-i
Full general
Designers National Security Agency
First published 1993 (SHA-0),
1995 (SHA-1)
Series (SHA-0), SHA-1, SHA-2, SHA-3
Certification FIPS PUB 180-4, CRYPTREC (Monitored)
Cipher detail
Digest sizes 160 bits
Cake sizes 512 bits
Construction Merkle–Damgård construction
Rounds eighty
Best public cryptanalysis
A 2011 assault past Marc Stevens tin can produce hash collisions with a complication between ii60.three and 265.3 operations.[1] The first public collision was published on 23 Feb 2017.[two] SHA-1 is prone to length extension attacks.

In cryptography, SHA-1 (Secure Hash Algorithm ane) is a cryptographically broken[three] [4] [5] [6] [7] [8] [9] simply nevertheless widely used hash part which takes an input and produces a 160-bit (20-byte) hash value known as a message digest – typically rendered every bit a hexadecimal number, twoscore digits long. It was designed by the United states of america National Security Agency, and is a U.S. Federal Information Processing Standard.[10]

Since 2005, SHA-ane has non been considered secure against well-funded opponents;[11] equally of 2010 many organizations have recommended its replacement.[12] [9] [xiii] NIST formally deprecated use of SHA-one in 2011 and disallowed its use for digital signatures in 2013. As of 2020[update], called-prefix attacks against SHA-1 are applied.[5] [vii] As such, it is recommended to remove SHA-one from products as soon equally possible and instead utilise SHA-2 or SHA-3. Replacing SHA-1 is urgent where it is used for digital signatures.

All major web browser vendors ceased credence of SHA-1 SSL certificates in 2017.[14] [8] [three] In February 2017, CWI Amsterdam and Google announced they had performed a standoff set on against SHA-1, publishing two dissimilar PDF files which produced the aforementioned SHA-one hash.[15] [2] Nevertheless, SHA-one is however secure for HMAC.[16]

Microsoft has discontinued SHA-one code signing support for Windows Update on August 7, 2020.

Development [edit]

One iteration inside the SHA-1 compression function:
A, B, C, D and E are 32-bit words of the state;
F is a nonlinear part that varies;
⋘ n {\displaystyle \lll _{due north}} denotes a left fleck rotation by northward places;
due north varies for each performance;
Westt is the expanded message give-and-take of round t;
Kt is the round abiding of circular t;
Addition denotes addition modulo ii32.

SHA-1 produces a message digest based on principles similar to those used past Ronald L. Rivest of MIT in the design of the MD2, MD4 and MD5 message digest algorithms, but generates a larger hash value (160 bits vs. 128 bits).

SHA-1 was developed every bit part of the U.S. Government'southward Capstone project.[17] The original specification of the algorithm was published in 1993 under the championship Secure Hash Standard, FIPS PUB 180, by U.S. authorities standards bureau NIST (National Establish of Standards and Technology).[18] [xix] This version is now ofttimes named SHA-0. It was withdrawn past the NSA shortly after publication and was superseded by the revised version, published in 1995 in FIPS PUB 180-i and commonly designated SHA-1. SHA-1 differs from SHA-0 only by a single bitwise rotation in the bulletin schedule of its compression role. According to the NSA, this was done to right a flaw in the original algorithm which reduced its cryptographic security, but they did not provide any further caption.[twenty] [21] Publicly bachelor techniques did indeed demonstrate a compromise of SHA-0, in 2004, before SHA-1 in 2017. Meet #Attacks

Applications [edit]

Cryptography [edit]

SHA-1 forms role of several widely used security applications and protocols, including TLS and SSL, PGP, SSH, S/MIME, and IPsec. Those applications tin can too apply MD5; both MD5 and SHA-i are descended from MD4.

SHA-i and SHA-2 are the hash algorithms required by police for use in sure U.S. government applications, including use within other cryptographic algorithms and protocols, for the protection of sensitive unclassified information. FIPS PUB 180-i also encouraged adoption and utilise of SHA-one past private and commercial organizations. SHA-1 is being retired from near authorities uses; the U.S. National Establish of Standards and Technology said, "Federal agencies should cease using SHA-1 for...applications that crave standoff resistance as soon as applied, and must use the SHA-2 family of hash functions for these applications after 2010" (emphasis in original),[22] though that was after relaxed to allow SHA-1 to be used for verifying old digital signatures and time stamps.[23]

A prime motivation for the publication of the Secure Hash Algorithm was the Digital Signature Standard, in which information technology is incorporated.

The SHA hash functions take been used for the footing of the SHACAL block ciphers.

Data integrity [edit]

Revision control systems such as Git, Mercurial, and Monotone apply SHA-1, not for security, merely to identify revisions and to ensure that the data has not changed due to accidental abuse. Linus Torvalds said about Git:

If you have disk corruption, if y'all have DRAM corruption, if you have any kind of problems at all, Git volition observe them. Information technology's not a question of if, it's a guarantee. You can have people who try to exist malicious. They won't succeed. ... Nobody has been able to break SHA-one, but the point is the SHA-1, every bit far as Git is concerned, isn't even a security characteristic. Information technology'southward purely a consistency check. The security parts are elsewhere, then a lot of people assume that since Git uses SHA-1 and SHA-1 is used for cryptographically secure stuff, they call back that, Okay, it's a huge security feature. Information technology has aught at all to do with security, it's just the best hash you can get. ...
I guarantee you, if you put your data in Git, yous can trust the fact that v years later on, afterward it was converted from your hd to DVD to any new engineering and you copied information technology along, five years later you can verify that the data you get back out is the exact same information y'all put in. ...
One of the reasons I care is for the kernel, we had a pause in on one of the BitKeeper sites where people tried to decadent the kernel source code repositories.[24] However Git does not require the second preimage resistance of SHA-1 as a security feature, since information technology volition always adopt to keep the earliest version of an object in example of collision, preventing an attacker from surreptitiously overwriting files.[25]

Cryptanalysis and validation [edit]

For a hash function for which L is the number of bits in the message digest, finding a message that corresponds to a given message digest tin ever exist done using a beast force search in approximately 2 L evaluations. This is called a preimage attack and may or may non be practical depending on L and the particular computing environment. However, a collision, consisting of finding two different messages that produce the same message digest, requires on boilerplate only about ane.ii × 2 L/2 evaluations using a birthday set on. Thus the strength of a hash function is usually compared to a symmetric cipher of half the message digest length. SHA-ane, which has a 160-flake message digest, was originally thought to take 80-bit forcefulness.

In 2005, cryptographers Xiaoyun Wang, Yiqun Lisa Yin, and Hongbo Yu produced collision pairs for SHA-0 and have found algorithms that should produce SHA-1 collisions in far fewer than the originally expected 280 evaluations.[26]

Some of the applications that use cryptographic hashes, similar countersign storage, are only minimally affected past a collision set on. Amalgam a password that works for a given business relationship requires a preimage attack, likewise equally access to the hash of the original password, which may or may not be fiddling. Reversing password encryption (e.g. to obtain a countersign to try against a user's business relationship elsewhere) is not made possible past the attacks. (However, even a secure password hash can't foreclose creature-force attacks on weak passwords.)

In the case of document signing, an aggressor could not merely imitation a signature from an existing document: The attacker would have to produce a pair of documents, i innocuous and ane damaging, and get the private cardinal holder to sign the innocuous document. There are practical circumstances in which this is possible; until the stop of 2008, it was possible to create forged SSL certificates using an MD5 collision.[27]

Due to the block and iterative structure of the algorithms and the absence of additional concluding steps, all SHA functions (except SHA-3[28]) are vulnerable to length-extension and fractional-message collision attacks.[29] These attacks allow an attacker to forge a message signed simply by a keyed hash – SHA(message || key) or SHA(primal || message) – by extending the message and recalculating the hash without knowing the central. A simple improvement to prevent these attacks is to hash twice: SHAd(message) = SHA(SHA(0 b || bulletin)) (the length of 0 b , zip block, is equal to the block size of the hash function).

Attacks [edit]

In early 2005, Vincent Rijmen and Elisabeth Oswald published an attack on a reduced version of SHA-one – 53 out of 80 rounds – which finds collisions with a computational effort of fewer than 280 operations.[xxx]

In Feb 2005, an attack past Xiaoyun Wang, Yiqun Lisa Yin, and Hongbo Yu was announced.[4] The attacks tin can discover collisions in the full version of SHA-i, requiring fewer than 269 operations. (A animate being-force search would require 280 operations.)

The authors write: "In particular, our analysis is built upon the original differential assault on SHA-0, the well-nigh standoff assail on SHA-0, the multiblock collision techniques, every bit well as the message modification techniques used in the collision search attack on MD5. Breaking SHA-ane would not be possible without these powerful belittling techniques."[31] The authors have presented a collision for 58-circular SHA-ane, found with two33 hash operations. The paper with the full assault description was published in August 2005 at the CRYPTO briefing.

In an interview, Yin states that, "Roughly, we exploit the post-obit 2 weaknesses: One is that the file preprocessing step is not complicated enough; another is that certain math operations in the commencement twenty rounds take unexpected security problems."[32]

On 17 August 2005, an comeback on the SHA-1 attack was announced on behalf of Xiaoyun Wang, Andrew Yao and Frances Yao at the CRYPTO 2005 Rump Session, lowering the complexity required for finding a collision in SHA-i to 263.[6] On 18 December 2007 the details of this consequence were explained and verified by Martin Cochran.[33]

Christophe De Cannière and Christian Rechberger further improved the set on on SHA-i in "Finding SHA-1 Characteristics: General Results and Applications,"[34] receiving the All-time Paper Award at ASIACRYPT 2006. A two-cake standoff for 64-round SHA-1 was presented, plant using unoptimized methods with 235 compression part evaluations. Since this attack requires the equivalent of about 235 evaluations, it is considered to be a significant theoretical break.[35] Their set on was extended further to 73 rounds (of lxxx) in 2010 by Grechnikov.[36] In society to find an actual standoff in the full eighty rounds of the hash office, however, tremendous amounts of reckoner fourth dimension are required. To that finish, a standoff search for SHA-1 using the distributed computing platform BOINC began August 8, 2007, organized past the Graz University of Applied science. The effort was abandoned May 12, 2009 due to lack of progress.[37]

At the Rump Session of CRYPTO 2006, Christian Rechberger and Christophe De Cannière claimed to have discovered a collision assail on SHA-1 that would allow an assaulter to select at least parts of the bulletin.[38] [39]

In 2008, an assault methodology by Stéphane Manuel reported hash collisions with an estimated theoretical complexity of ii51 to two57 operations.[40] However he later retracted that claim after finding that local collision paths were non really independent, and finally quoting for the nigh efficient a collision vector that was already known before this work.[41]

Cameron McDonald, Philip Hawkes and Josef Pieprzyk presented a hash collision assault with claimed complication ii52 at the Rump Session of Eurocrypt 2009.[42] Withal, the accompanying paper, "Differential Path for SHA-ane with complexity O(252)" has been withdrawn due to the authors' discovery that their estimate was wrong.[43]

I attack against SHA-1 was Marc Stevens[44] with an estimated toll of $ii.77M(2012) to break a single hash value by renting CPU power from cloud servers.[45] Stevens developed this attack in a project called HashClash,[46] implementing a differential path set on. On 8 November 2010, he claimed he had a fully working nearly-collision attack against total SHA-ane working with an estimated complexity equivalent to two57.5 SHA-1 compressions. He estimated this attack could be extended to a full standoff with a complexity around 261.

The SHAppening [edit]

On 8 October 2015, Marc Stevens, Pierre Karpman, and Thomas Peyrin published a freestart standoff attack on SHA-ane'due south compression office that requires only 257 SHA-1 evaluations. This does not straight translate into a collision on the total SHA-1 hash function (where an aggressor is not able to freely choose the initial internal country), but undermines the security claims for SHA-1. In particular, it was the outset time that an attack on full SHA-1 had been demonstrated; all before attacks were as well expensive for their authors to carry them out. The authors named this significant quantum in the cryptanalysis of SHA-i The SHAppening.[9]

The method was based on their earlier piece of work, as well as the auxiliary paths (or boomerangs) speed-upward technique from Joux and Peyrin, and using high performance/cost efficient GPU cards from NVIDIA. The collision was found on a sixteen-node cluster with a total of 64 graphics cards. The authors estimated that a like collision could be establish by buying US$2,000 of GPU time on EC2.[9]

The authors estimated that the toll of renting enough of EC2 CPU/GPU fourth dimension to generate a total collision for SHA-1 at the time of publication was betwixt US$75K and 120K, and noted that was well inside the upkeep of criminal organizations, not to mention national intelligence agencies. As such, the authors recommended that SHA-i exist deprecated as quickly every bit possible.[9]

SHAttered – first public collision [edit]

On 23 February 2017, the CWI (Centrum Wiskunde & Informatica) and Google appear the SHAttered attack, in which they generated two unlike PDF files with the same SHA-one hash in roughly two63.ane SHA-1 evaluations. This attack is about 100,000 times faster than brute forcing a SHA-1 collision with a birthday attack, which was estimated to take 280 SHA-1 evaluations. The assault required "the equivalent processing power of 6,500 years of single-CPU computations and 110 years of unmarried-GPU computations".[2]

Birthday-Well-nigh-Standoff Attack – first practical chosen-prefix attack [edit]

On 24 April 2019 a paper by Gaëtan Leurent and Thomas Peyrin presented at Eurocrypt 2019 described an enhancement to the previously best chosen-prefix attack in Merkle–Damgård–like assimilate functions based on Davies–Meyer cake ciphers. With these improvements, this method is capable of finding chosen-prefix collisions in approximately 268 SHA-1 evaluations. This is approximately i billion times faster (and now usable for many targeted attacks, thanks to the possibility of choosing a prefix, for example malicious lawmaking or faked identities in signed certificates) than the previous assault'southward ii77.1 evaluations (but without called prefix, which was impractical for most targeted attacks considering the establish collisions were almost random)[47] and is fast enough to be applied for resourceful attackers, requiring approximately $100,000 of deject processing. This method is also capable of finding chosen-prefix collisions in the MD5 function, just at a complexity of two46.3 does not surpass the prior best available method at a theoretical level (239), though potentially at a practical level (≤249).[48] [49] This attack has a retentiveness requirement of 500+ GB.

On v January 2020 the authors published an improved set on.[7] In this paper they demonstrate a chosen-prefix collision set on with a complication of 263.4, that at the time of publication would price 45k USD per generated collision.

SHA-0 [edit]

At CRYPTO 98, two French researchers, Florent Chabaud and Antoine Joux, presented an attack on SHA-0: collisions can be establish with complication two61, fewer than the ii80 for an ideal hash part of the same size.[50]

In 2004, Biham and Chen found near-collisions for SHA-0 – 2 letters that hash to nearly the aforementioned value; in this case, 142 out of the 160 $.25 are equal. They also found total collisions of SHA-0 reduced to 62 out of its eighty rounds.[51]

Afterward, on 12 August 2004, a collision for the full SHA-0 algorithm was appear by Joux, Carribault, Lemuet, and Jalby. This was done by using a generalization of the Chabaud and Joux attack. Finding the collision had complexity 251 and took about 80,000 processor-hours on a supercomputer with 256 Itanium 2 processors (equivalent to 13 days of full-time apply of the computer).

On 17 August 2004, at the Rump Session of CRYPTO 2004, preliminary results were announced by Wang, Feng, Lai, and Yu, nearly an set on on MD5, SHA-0 and other hash functions. The complexity of their attack on SHA-0 is 2forty, significantly meliorate than the attack by Joux et al. [52] [53]

In February 2005, an set on by Xiaoyun Wang, Yiqun Lisa Yin, and Hongbo Yu was appear which could find collisions in SHA-0 in ii39 operations.[four] [54]

Another attack in 2008 applying the boomerang attack brought the complication of finding collisions downward to two33.6, which was estimated to take 1 hour on an average PC from the year 2008.[55]

In low-cal of the results for SHA-0, some experts[ who? ] suggested that plans for the utilize of SHA-one in new cryptosystems should exist reconsidered. After the CRYPTO 2004 results were published, NIST announced that they planned to phase out the employ of SHA-one by 2010 in favor of the SHA-2 variants.[56]

Official validation [edit]

Implementations of all FIPS-canonical security functions tin be officially validated through the CMVP program, jointly run by the National Found of Standards and Technology (NIST) and the Communications Security Establishment (CSE). For breezy verification, a bundle to generate a high number of test vectors is fabricated available for download on the NIST site; the resulting verification, still, does not supercede the formal CMVP validation, which is required by police for certain applications.

As of Dec 2013[update], there are over 2000 validated implementations of SHA-1, with fourteen of them capable of treatment messages with a length in $.25 not a multiple of eight (see SHS Validation List Archived 2011-08-23 at the Wayback Machine).

Examples and pseudocode [edit]

Example hashes [edit]

These are examples of SHA-ane message digests in hexadecimal and in Base64 binary to ASCII text encoding.

  • SHA1("The quick brown fox jumps over the lazy dog")
    • Outputted hexadecimal: 2fd4e1c67a2d28fced849ee1bb76e7391b93eb12
    • Outputted Base64 binary to ASCII text encoding: L9ThxnotKPzthJ7hu3bnORuT6xI=

Even a small alter in the message volition, with overwhelming probability, result in many $.25 changing due to the avalanche effect. For example, irresolute dog to cog produces a hash with different values for 81 of the 160 $.25:

  • SHA1("The quick brown play a trick on jumps over the lazy cog")
    • Outputted hexadecimal: de9f2c7fd25e1b3afad3e85a0bd17d9b100db4b3
    • Outputted Base64 binary to ASCII text encoding: 3p8sf9JeGzr60+haC9F9mxANtLM=

The hash of the naught-length string is:

  • SHA1("")
    • Outputted hexadecimal: da39a3ee5e6b4b0d3255bfef95601890afd80709
    • Outputted Base64 binary to ASCII text encoding: 2jmj7l5rSw0yVb/vlWAYkK/YBwk=

SHA-1 pseudocode [edit]

Pseudocode for the SHA-1 algorithm follows: 

                      Note i: All variables are unsigned 32-flake quantities and wrap modulo 232              when calculating, except for                                ml, the message length, which is a 64-chip quantity, and                                hh, the message assimilate, which is a 160-flake quantity.                                Note ii: All constants in this pseudo code are in big endian.                                Within each word, the most significant byte is stored in the leftmost byte position                                Initialize variables:                    h0 = 0x67452301 h1 = 0xEFCDAB89 h2 = 0x98BADCFE h3 = 0x10325476 h4 = 0xC3D2E1F0  ml = message length in bits (always a multiple of the number of bits in a graphic symbol).                      Pre-processing:                    append the chip '1' to the message eastward.thou. past adding 0x80 if message length is a multiple of 8 bits. append 0 ≤ k < 512 bits '0', such that the resulting message length in          bits          is congruent to −64 ≡ 448 (modernistic 512) append ml, the original message length in bits, equally a 64-bit large-endian integer.     Thus, the total length is a multiple of 512 $.25.                      Process the bulletin in successive 512-bit chunks:                    break bulletin into 512-bit chunks          for          each chunk     break chunk into sixteen 32-flake big-endian words w[i], 0 ≤ i ≤ xv                      Message schedule: extend the sixteen 32-scrap words into 80 32-chip words:                    for          i          from          16 to 79                      Note three: SHA-0 differs by not having this leftrotate.                    w[i] = (w[i-3]          xor          westward[i-8]          xor          w[i-14]          xor          w[i-16])          leftrotate          ane                      Initialize hash value for this clamper:                    a = h0     b = h1     c = h2     d = h3     e = h4                      Principal loop:                    [10]          [57]          for          i          from          0          to          79          if          0 ≤ i ≤ 19          and then          f = (b          and          c)          or          ((non          b)          and          d)             k = 0x5A827999          else if          20 ≤ i ≤ 39             f = b          xor          c          xor          d             thousand = 0x6ED9EBA1          else if          40 ≤ i ≤ 59             f = (b          and          c)          or          (b          and          d)          or          (c          and          d)              grand = 0x8F1BBCDC          else if          60 ≤ i ≤ 79             f = b          xor          c          xor          d             k = 0xCA62C1D6          temp = (a          leftrotate          v) + f + e + thou + west[i]         due east = d         d = c         c = b          leftrotate          30         b = a         a = temp                      Add this chunk's hash to result then far:                    h0 = h0 + a     h1 = h1 + b      h2 = h2 + c     h3 = h3 + d     h4 = h4 + e                      Produce the final hash value (big-endian) every bit a 160-flake number:                    hh = (h0          leftshift          128)          or          (h1          leftshift          96)          or          (h2          leftshift          64)          or          (h3          leftshift          32)          or          h4

The number hh is the message digest, which tin can be written in hexadecimal (base 16).

The called constant values used in the algorithm were causeless to be nothing up my sleeve numbers:

  • The four round constants grand are 230 times the square roots of 2, iii, 5 and 10. Nonetheless they were incorrectly rounded to the nearest integer instead of being rounded to the nearest odd integer, with equilibrated proportions of nil and one bits. As well, choosing the square root of 10 (which is not a prime number) fabricated it a common gene for the two other chosen foursquare roots of primes 2 and v, with perhaps usable arithmetic backdrop across successive rounds, reducing the strength of the algorithm against finding collisions on some bits.
  • The first four starting values for h0 through h3 are the same with the MD5 algorithm, and the 5th (for h4) is similar. Nevertheless they were not properly verified for being resistant against inversion of the few kickoff rounds to infer possible collisions on some bits, usable by multiblock differential attacks.

Instead of the formulation from the original FIPS PUB 180-1 shown, the following equivalent expressions may be used to compute f in the primary loop above: 

                      Bitwise pick between            c              and            d, controlled past            b.                    (0  ≤ i ≤ 19): f = d          xor          (b          and          (c          xor          d))                      (culling one)                    (0  ≤ i ≤ 19): f = (b          and          c)          or          ((not          b)          and          d)                      (alternative 2)                    (0  ≤ i ≤ 19): f = (b          and          c)          xor          ((non          b)          and          d)                      (culling 3)                    (0  ≤ i ≤ nineteen): f = vec_sel(d, c, b)                      (alternative iv)                    [premo08]                      Bitwise bulk office.                    (40 ≤ i ≤ 59): f = (b          and          c)          or          (d          and          (b          or          c))                      (alternative 1)                    (40 ≤ i ≤ 59): f = (b          and          c)          or          (d          and          (b          xor          c))                      (alternative 2)                    (40 ≤ i ≤ 59): f = (b          and          c)          xor          (d          and          (b          xor          c))                      (culling 3)                    (40 ≤ i ≤ 59): f = (b          and          c)          xor          (b          and          d)          xor          (c          and          d)                      (alternative iv)                    (40 ≤ i ≤ 59): f = vec_sel(c, b, c          xor          d)                      (culling v)

It was besides shown[58] that for the rounds 32–79 the computation of: 

w[i] = (w[i-iii]          xor          w[i-viii]          xor          w[i-14]          xor          west[i-16])          leftrotate          1

tin exist replaced with: 

w[i] = (west[i-6]          xor          w[i-sixteen]          xor          westward[i-28]          xor          w[i-32])          leftrotate          ii

This transformation keeps all operands 64-scrap aligned and, by removing the dependency of w[i] on west[i-iii], allows efficient SIMD implementation with a vector length of 4 like x86 SSE instructions.

Comparison of SHA functions [edit]

In the table beneath, internal state means the "internal hash sum" later each compression of a data block.

Comparing of SHA functions
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Algorithm and variant Output size
(bits) 		Internal country size
($.25) 		Block size
(bits) 		Rounds Operations Security against collision attacks
(bits) 		Security against length extension attacks
(bits) 		Performance on Skylake (median cpb)[59] First published
Long messages 8 bytes
MD5 (as reference) 128 128
(4 × 32) 		512 64 And, Xor, Rot, Add (modern 232), Or ≤ 18
(collisions found)[lx] 		0 4.99 55.00 1992
SHA-0 160 160
(5 × 32) 		512 eighty And, Xor, Rot, Add together (modernistic 232), Or < 34
(collisions found)		 0 ≈ SHA-ane ≈ SHA-1 1993
SHA-1 < 63
(collisions found)[61] 		iii.47 52.00 1995
SHA-ii SHA-224
SHA-256 		224
256		 256
(viii × 32) 		512 64 And, Xor, Rot, Add (mod 232), Or, Shr 112
128		 32
0		 7.62
7.63		 84.l
85.25		 2004
2001
SHA-384 384 512
(eight × 64) 		1024 eighty And, Xor, Rot, Add (mod ii64), Or, Shr 192 128 (≤ 384) 5.12 135.75 2001
SHA-512 512 512
(8 × 64) 		1024 80 And, Xor, Rot, Add (mod 264), Or, Shr 256 0[62] 5.06 135.fifty 2001
SHA-512/224
SHA-512/256 		224
256		 512
(viii × 64) 		1024 80 And, Xor, Rot, Add (mod two64), Or, Shr 112
128		 288
256		 ≈ SHA-384 ≈ SHA-384 2012
SHA-3 SHA3-224
SHA3-256
SHA3-384
SHA3-512 		224
256
384
512		 1600
(five × 5 × 64) 		1152
1088
832
576		 24 [63] And, Xor, Rot, Not 112
128
192
256		 448
512
768
1024		 8.12
8.59
11.06
xv.88		 154.25
155.50
164.00
164.00		 2015
SHAKE128
SHAKE256 		d (arbitrary)
d (arbitrary) 		1344
1088		 min(d/2, 128)
min(d/2, 256) 		256
512 		seven.08
viii.59		 155.25
155.l

Implementations [edit]

Beneath is a listing of cryptography libraries that back up SHA-1:

  • Botan
  • Boisterous Castle
  • cryptlib
  • Crypto++
  • Libgcrypt
  • Mbed TLS
  • Nettle
  • LibreSSL
  • OpenSSL
  • GnuTLS

Hardware acceleration is provided past the post-obit processor extensions:

  • Intel SHA extensions: Available on some Intel and AMD x86 processors.
  • VIA PadLock

Meet besides [edit]

  • Comparison of cryptographic hash functions
  • Hash office security summary
  • International Association for Cryptologic Research
  • Secure Hash Standard

Notes [edit]

  1. ^ Stevens, Marc (June 19, 2012). Attacks on Hash Functions and Applications (PDF) (Thesis). Leiden University. hdl:1887/19093. ISBN9789461913173. OCLC 795702954.
  2. ^ a b c Stevens, Marc; Bursztein, Elie; Karpman, Pierre; Albertini, Ange; Markov, Yarik (2017). Katz, Jonathan; Shacham, Hovav (eds.). The First Standoff for Full SHA-ane (PDF). Advances in Cryptology – CRYPTO 2017. Lecture Notes in Computer Scientific discipline. Vol. 10401. Springer. pp. 570–596. doi:10.1007/978-3-319-63688-7_19. ISBN9783319636870. Archived from the original (PDF) on May 15, 2018. Retrieved February 23, 2017. Lay summary – Google Security Blog (Feb 23, 2017).
  3. ^ a b "The end of SHA-1 on the Public Web". Mozilla Security Blog . Retrieved 2019-05-29 .
  4. ^ a b c "SHA-1 Broken – Schneier on Security".
  5. ^ a b "Critical flaw demonstrated in common digital security algorithm". Nanyang Technological University, Singapore. 24 January 2020.
  6. ^ a b "New Cryptanalytic Results Against SHA-1 – Schneier on Security".
  7. ^ a b c Gaëtan Leurent; Thomas Peyrin (2020-01-05). "SHA-1 is a Shambles First Chosen-Prefix Collision on SHA-1 and Application to the PGP Spider web of Trust" (PDF). Cryptology ePrint Annal, Report 2020/014.
  8. ^ a b "Google volition drop SHA-1 encryption from Chrome past January ane, 2017". VentureBeat. 2015-12-18. Retrieved 2019-05-29 .
  9. ^ a b c d due east Stevens1, Marc; Karpman, Pierre; Peyrin, Thomas. "The SHAppening: freestart collisions for SHA-one". Retrieved 2015-10-09 .
  10. ^ a b "Archived re-create" (PDF). Archived from the original (PDF) on 2020-01-07. Retrieved 2019-09-23 . {{cite spider web}}: CS1 maint: archived copy as title (link)
  11. ^ Schneier, Bruce (Feb 18, 2005). "Schneier on Security: Cryptanalysis of SHA-1".
  12. ^ "NIST.gov – Computer Security Sectionalization – Estimator Security Resources Center". Archived from the original on 2011-06-25. Retrieved 2019-01-05 .
  13. ^ Schneier, Bruce (viii October 2015). "SHA-one Freestart Collision". Schneier on Security.
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References [edit]

  • Eli Biham, Rafi Chen, Near-Collisions of SHA-0, Cryptology ePrint Archive, Report 2004/146, 2004 (appeared on CRYPTO 2004), IACR.org
  • Xiaoyun Wang, Hongbo Yu and Yiqun Lisa Yin, Efficient Collision Search Attacks on SHA-0, Crypto 2005
  • Xiaoyun Wang, Yiqun Lisa Yin and Hongbo Yu, Finding Collisions in the Full SHA-i, Crypto 2005
  • Henri Gilbert, Helena Handschuh: Security Assay of SHA-256 and Sisters. Selected Areas in Cryptography 2003: pp175–193
  • An Illustrated Guide to Cryptographic Hashes
  • "Proposed Revision of Federal Information Processing Standard (FIPS) 180, Secure Hash Standard". Federal Annals. 59 (131): 35317–35318. 1994-07-11. Retrieved 2007-04-26 . [ permanent expressionless link ]
  • A. Cilardo, Fifty. Esposito, A. Veniero, A. Mazzeo, 5. Beltran, East. Ayugadé, A CellBE-based HPC application for the analysis of vulnerabilities in cryptographic hash functions, High Operation Calculating and Communication international conference, August 2010

External links [edit]

  • CSRC Cryptographic Toolkit – Official NIST site for the Secure Hash Standard
  • FIPS 180-4: Secure Hash Standard (SHS)
  • RFC 3174 (with sample C implementation)
  • Interview with Yiqun Lisa Yin concerning the attack on SHA-one
  • Explanation of the successful attacks on SHA-1 (3 pages, 2006)
  • Cryptography Research – Hash Standoff Q&A
  • SHA-ane at Curlie
  • Lecture on SHA-i (1h 18m) on YouTube by Christof Paar

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Source: https://en.wikipedia.org/wiki/SHA-1

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