SHA-1

수학노트
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  • The SHA224, SHA256, SHA384 and SHA512 families of functions operate in the same way as for the SHA1 functions.[1]
  • In 2017, a number of companies announced they would no longer support SHA-1 signing.[2]
  • Collision attacks are possible, where cyber criminals can cause MD5 and SHA1 collisions to steal data and cause other problems.[2]
  • When 2017 came, the browser companies all stopped accepting SHA1 signing.[2]
  • The rest of the computer industry that exchanges data also began to shift away from SHA1 as a signing algorithm.[2]
  • It’s well known that SHA-1 is no longer considered a secure cryptographic hash function.[3]
  • SHA-1 (SHA stands for Secure Hash Algorithm) in 1995 as a standard for cryptographically secure hashing.[3]
  • Computing a SHA-1 collision might be feasible in 2016, and there's a chance that chosen-prefix attacks also become feasible.[3]
  • A hash collision in SHA-1 is bad, but it’s not what matters for web security.[3]
  • If your site is still using SHA-1 certificates, then visitors to your website in Chrome will be met with this warning.[4]
  • However, experts have known since 2005 that the original SHA-1 certificate was vulnerable to attack.[4]
  • In response to rising concerns, the NIST (National Institute of Standards and Technology) officially deprecated SHA-1 in 2011.[4]
  • SHA-1 n practice using a simulated collision attack.[4]
  • In non-technical terms, an attacker can more easily create two DNS records that have the same SHA-1 hash value.[5]
  • This improved attack has serious consequences for all parts of the Internet that use SHA-1.[5]
  • In DNSSEC, SHA-1 is part of some signature algorithms which have been used since the early days of securing the DNS.[5]
  • In fact, more than 250 top-level domains (TLDs) are still using algorithms with SHA-1.[5]
  • and we recommend they also support SHA-1 for backward compatibility during the transition period.[6]
  • Hash Algorithm 1 or SHA-1 is a cryptographic hash function designed by the United States National Security Agency and released in 1995.[7]
  • The team published a practical technique showing how to generate a collision bringing the fears that SHA-1 was insecure to reality.[7]
  • This is a big deal because even though many organizations have stopped using SHA-1, underlying systems still often rely on SHA-1.[7]
  • Software updates, ISO checksums, PGP signatures, digital certificate signatures, git, and others still make use of SHA-1 for data integrity.[7]
  • However SHA-1 was adopted in 1995, a long time ago in internet years.[8]
  • It works the same way as SHA-1, but produces a longer fingerprint when used on a message.[8]
  • The hard work required to transition from SHA-1 to SHA-2 has already been taken care of.[8]
  • SHA-1 is a cryptographic hash function, mapping bitstrings of arbitrary finite length to strings of fixed length.[9]
  • SHA-1 has been broken in 2005 by a theoretical collision attack.[9]
  • In 2017, a practical collision attack on SHA-1 was reported, and the first known instance of a SHA-1 collision was provided.[9]
  • Commercial products that use cryptography from reputable vendors are likely to have phased out SHA-1 by now - but you might like to check![9]
  • We’ve previously made several announcements about Google Chrome's deprecation plans for SHA-1 certificates.[10]
  • We may also remove support before 2019 if there is a catastrophic cryptographic break of SHA-1.[10]
  • The good news is, almost no one is still using SHA-1, so you don’t need to rush out and install any patches.[11]
  • Google publicly broke one of the major algorithms in web encryption, called SHA-1.[11]
  • SHA-1 is a hashing function, which produces a digital fingerprint from a given file.[11]
  • As a result, most sites have already dropped SHA-1.[11]
  • SHA1 generates an almost-unique 160-bit (20-byte) signature for a text.[12]
  • SHA-1 is is no longer recommended for cryptographic purposes (SHA-256 or SHA-3 are now preferred).[12]
  • Google have now achieved a collision attack on SHA-1.[12]
  • As of January 16, 2015, CAs will be forbidden to issue SHA-1 Certificates that expire past December 31, 2016.[13]
  • Note that SHA-1 SSL Certificates that are valid past 1/1/2017 will show as untrusted in Chromium 41.[13]
  • Note that after January 01, 2017, Firefox will not trust any SHA-1 Certificate.[13]
  • Open a terminal and run the keytool utility provided with Java to get the SHA-1 fingerprint of the certificate.[14]
  • According to the official Git hash function transition document, the insecurity of SHA-1 has been known for some time.[15]
  • The document states, “Over time some flaws in SHA-1 have been discovered by security researchers.[15]
  • Git plans on migrating from SHA-1 to SHA-265.[15]
  • We show that collisions of SHA-1 can be found with complexity less than 269 hash operations.[16]
  • We strongly advise to remove SHA-1 from those type of applications as soon as possible.[17]
  • We exemplify our cryptanalysis by creating a pair of PGP/GnuPG keys with different identities, but colliding SHA-1 certificates.[17]
  • A SHA-1 certification of the first key can therefore be transferred to the second key, leading to an impersonation attack.[17]
  • This proves that SHA-1 signatures now offer virtually no security in practice.[17]
  • “Our work show that SHA-1 is now fully and practically broken for use in digital signatures.[18]
  • “SHA-1 usage has significantly decreased in the last years; in particular web browsers now reject certificates signed with SHA-1.[18]
  • However, SHA-1 signatures are still supported in a large number of applications.[18]
  • Hash computing the SHA1 checksum.[19]
  • From RFC 3174 - The US Secure Hash Algorithm 1: "SHA-1 produces a 160-bit output called a message digest.[20]
  • customers prepare for and move to SHA-2, the set of cryptographic hash functions that have succeeded SHA-1.[21]
  • Over time, several continued cryptographic attacks against SHA-1 started to shorten its effective key length.[21]
  • The root CA’s own CA certificate does not have to be migrated to SHA-2 even if it is still SHA-1.[21]
  • Although no significant cryptographic weakness has been found in SHA-2, it's considered algorithmically related to SHA-1.[21]
  • First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust”.[22]
  • The following example shows a valid DSig 1.0 SHA1 resinfo extension with two SHA1 hashes of the referenced information resource.[23]
  • Given the footprint of SHA-1, Leurent and Peyrin said that users of GnuPG, OpenSSL and Git could be in immediate danger.[24]
  • But that’s not the only remaining bastion for SHA-1.[24]
  • And many non-Web applications that rely on HTTPS encryption still accept SHA-1 certificates.[24]
  • “Our work shows that SHA-1 is now fully and practically broken for use in digital signatures,” Leurent and Peyrin wrote in their paper.[24]
  • Any application that relies on SHA-1 for digital signatures, file integrity, or file identification is potentially vulnerable.[25]
  • Any Certification Authority abiding by the CA/Browser Forum regulations is not allowed to issue SHA-1 certificates anymore.[25]
  • Starting from version 56, released in January 2017, Chrome will consider any website protected with a SHA-1 certificate as insecure.[25]
  • GIT strongly relies on SHA-1 for the identification and integrity checking of all file objects and commits.[25]
  • It was withdrawn shortly after publication due to an undisclosed "significant flaw" and replaced by the slightly revised version SHA-1.[26]
  • Cryptographic weaknesses were discovered in SHA-1, and the standard was no longer approved for most cryptographic uses after 2010.[26]
  • Does this mean that achieving SHA-1 collisions is now within the grasp of most attackers?[27]
  • NIST formally deprecated use of SHA-1 in 2011 and disallowed its use for digital signatures in 2013.[28]
  • As such, it is recommended to remove SHA-1 from products as soon as possible and instead use SHA-2 or SHA-3.[28]
  • SHA-1 differs from SHA-0 only by a single bitwise rotation in the message schedule of its compression function.[28]
  • Publicly available techniques did indeed demonstrate a compromise of SHA-0, in 2004, before SHA-1 in 2017.[28]
  • This online tool allows you to generate the SHA1 hash from any string.[29]
  • A growing body of research showing the weaknesses of SHA-1 prompted a revaluation.[30]
  • The deadline for issuing new SSL certificates with SHA-1 hashes was December 31st, 2015.[30]
  • But over the last three years SHA-1 certificates have almost entirely died out.[30]
  • Today, if you encounter a SHA-1 certificate, you will see an unmistakable warning.[30]

소스

  1. ↑ SHA1.html
  2. ↑ 2.0 2.1 2.2 2.3 Why use SHA256 instead of SHA1?
  3. ↑ 3.0 3.1 3.2 3.3 Why it’s harder to forge a SHA-1 certificate than it is to find a SHA-1 collision
  4. ↑ 4.0 4.1 4.2 4.3 SHA-1 Deprecation
  5. ↑ 5.0 5.1 5.2 5.3 It’s Time to Move Away From Using SHA-1 in the DNS
  6. ↑ Security Bulletin Deprecation notice for SHA-1 Hash Algorithm
  7. ↑ 7.0 7.1 7.2 7.3 SHA-1 Has Been Compromised In Practice
  8. ↑ 8.0 8.1 8.2 What is SHA-1 / SHA-2 ?
  9. ↑ 9.0 9.1 9.2 9.3 The SHA-1 Attack Further Emphasizes the Need for Crypto-Agility
  10. ↑ 10.0 10.1 A further update on SHA-1 certificates in Chrome
  11. ↑ 11.0 11.1 11.2 11.3 Google just cracked one of the building blocks of web encryption (but don’t worry)
  12. ↑ 12.0 12.1 12.2 Movable Type Scripts
  13. ↑ 13.0 13.1 13.2 SHA-256 Rollout :: SHA-256 Rollout :: GlobalSign Support
  14. ↑ Authenticating Your Client
  15. ↑ 15.0 15.1 15.2 Git Transitioning Away from the Aging SHA-1 Hash – The New Stack
  16. ↑ Finding Collisions in the Full SHA-1
  17. ↑ 17.0 17.1 17.2 17.3 SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust
  18. ↑ 18.0 18.1 18.2 SHA-1 ‘Fully and Practically Broken’ By New Collision
  19. ↑ The Go Programming Language
  20. ↑ PHP sha1() Function
  21. ↑ 21.0 21.1 21.2 21.3 All you need to know about the move from SHA-1 to SHA-2 encryption
  22. ↑ Researchers demonstrate practical break of SHA-1 hash function
  23. ↑ SHA1 version 1.0
  24. ↑ 24.0 24.1 24.2 24.3 Exploit Fully Breaks SHA-1, Lowers the Attack Bar
  25. ↑ 25.0 25.1 25.2 25.3 SHAttered
  26. ↑ 26.0 26.1 Secure Hash Algorithms
  27. ↑ The SHA1 hash function is now completely unsafe
  28. ↑ 28.0 28.1 28.2 28.3 Wikipedia
  29. ↑ SHA1 Hash Generator Online
  30. ↑ 30.0 30.1 30.2 30.3 The Difference Between SHA-1, SHA-2 and SHA-256 Hash Algorithms
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