📄 hash.htm
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width=400><BR><FONT face="Arial, Helvetica, sans-serif" size=3><B>Secure
Hashing</B></FONT> </DIV><BR>
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<DIV align=left><FONT face="Arial, Helvetica, sans-serif"
color=#ffffff size=2><B>Approved Algorithms<A
name=aFIPSAlgs></A></B></FONT><BR></DIV></TD></TR>
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<TD>There are five (5) <A
href="http://csrc.nist.gov/CryptoToolkit/Hash.html#note">Approved*</A>
algorithms for generating a condensed representation of a message
(message digest): <B>SHA-1</B>, <B>SHA-224</B>, <B>SHA-256</B>,
<B>SHA-384</B>, and <B>SHA-512</B>.<BR><BR><A
name=aSHA1UsageStatment>March 15, 2006:</A> <B>The SHA-2 family of
hash functions (i.e., SHA-224, SHA-256, SHA-384 and SHA-512) may be
used by Federal agencies for all applications using secure hash
algorithms.</B> Federal agencies <B>should</B> stop using SHA-1 for
digital signatures, digital time stamping and other applications
that require collision resistance as soon as practical, and must use
the SHA-2 family of hash functions for these applications after
2010. After 2010, Federal agencies may use SHA-1 only for the
following applications: hash-based message authentication codes
(HMACs); key derivation functions (KDFs); and random number
generators (RNGs). Regardless of use, NIST encourages application
and protocol designers to use the SHA-2 family of hash functions for
all new applications and protocols.<BR></TD></TR></TBODY></TABLE>
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<P><B>SHA-1,</B></P>
<P><B>SHA-224,</B></P>
<P><B>SHA-256,</B></P>
<P><B>SHA-384, and</B></P>
<P><B>SHA-512</B></P></TD>
<TD><A
href="http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf"
target=_top><B>FIPS 180-2</B>, <I>Secure Hash Standard
(SHS)</I></A>, August 2002. <BR><BR>On August 26, 2002, NIST <A
href="http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2002_register&docid=02-21599-filed.pdf">announced</A>
the approval of FIPS 180-2, Secure Hash Standard, which contains the
specifications for the Secure Hash Algorithms (SHA-1, SHA-256,
SHA-384, and SHA-512) with several examples.<BR><BR>On February 25,
2004, a <A
href="http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf"
target=_top>change notice</A> was included that specifies SHA-224
and discusses truncation of the hash function output in order to
provide interoperability.<BR><BR>In August, 2004, researchers
announced that they discovered a new way to break a number of
cryptographic hash algorithms. Those initial attacks did not break
any of the SHA family algorithms, as is reflected in <A
href="http://csrc.nist.gov/hash_standards_comments.pdf"
target=_top>NIST's comments at that time</A>.<BR><BR>In February,
2005, however, researchers announced an attack on the full SHA-1
algorithm. Click <A
href="http://csrc.nist.gov/CryptoToolkit/shs/NISTHashComments-final.pdf"
target=_top>here</A> for NIST's brief comments on these latest
attacks. (Statement revised April 25, 2006.)<BR><BR><A
href="http://www.nist.gov/hash-function" target=_top>Second
Cryptographic Hash Workshop</A><BR>August 24-25, 2006, UCSB, Santa
Barbara<BR><BR>NIST plans to host a series of public workshops to
focus on hash function research in preparation for developing
additional hash function(s) through a public competition.
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color=#ffffff size=2><B>Testing/Products<A
name=aTesting></A></B></FONT><BR></DIV></TD></TR>
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<TD><A href="http://csrc.nist.gov/cryptval/shs.htm"
target=_top>Testing requirements and validation lists</A> are
available for SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512.
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color=#ffffff size=2><B>Additional Information<A
name=aAddInfo></A></B></FONT><BR></DIV></TD></TR>
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<TD><A href="http://www.nist.gov/hash-function" target=_top>Second
Cryptographic Hash Workshop</A><BR>August 24-25, 2006, UCSB, Santa
Barbara<BR><BR>As a follow-up to the first Cryptographic Hash
Workshop held on Oct. 31-Nov. 1, 2005, NIST plans to host a series
of public workshops to focus on hash function research in
preparation for developing additional hash function(s) through a
public competition. The next workshop will be held on August 24-25
at UCSB, Santa Barbara, in conjunction with Crypto 2006.<BR><BR><A
href="http://csrc.nist.gov/pki/HashWorkshop/2005/program.htm"
target=_top>Cryptographic Hash Workshop</A><BR>October 31 - November
1, 2005<BR><BR>Recently a team of researchers reported that the
SHA-1 function offers significantly less collision resistance than
could be expected from a cryptographic hash function of its ouput
size. NIST hosted a workshop to solicit public input in how best to
respond to the current state of research in this area. An <A
href="http://csrc.nist.gov/pki/HashWorkshop/2005/program.htm"
target=_top>agenda and presentations</A> from this workshop are
available.</TD></TR></TBODY></TABLE></TR></TBODY></TABLE>
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<A name=note></A>
<P align=justify>* An algorithm or technique that is either specified in a
FIPS or NIST Recommendation </P>
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<FONT face="Verdana, Arial, Helvetica, sans-serif" size=1><I>Last updated:
<!-- #BeginDate format:Am1 -->April 12, 2007<!-- #EndDate --> <BR>Page
created: December 21, 2000</I></FONT><BR><FONT
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