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	RFC 2104 (rfc2104) - HMAC: Keyed-Hashing for Message Authentication
		The cryptographic strength of HMAC depends on the properties of the underlying hash function.
		Definition of HMAC The definition of HMAC requires a cryptographic hash function, which we denote by H, and a secret key K. We assume H to be a cryptographic hash function where data is hashed by iterating a basic compression function on blocks of data.
		The strongest attack known against HMAC is based on the frequency of collisions for the hash function H ("birthday attack") [PV,BCK2], and is totally impractical for minimally reasonable hash functions.
	www.faqs.org /rfcs/rfc2104.html (2297 words)

	HMAC - Wikipedia, the free encyclopedia
		The cryptographic strength of the HMAC depends upon the cryptographic strength of the underlying hash function, on the size and quality of the key and the size of the hash output length in bits.
		The size of the output of HMAC is the same as that of the underlying hash function (128 or 160 bits in the case of MD5 and SHA-1), although it can be truncated if desired.
		The construction and analysis of HMACs was first published in 1996 by Mihir Bellare, Ran Canetti, and Hugo Krawczyk, who also wrote RFC 2104.
	en.wikipedia.org /wiki/HMAC (687 words)

	Interesting papers on HMAC and NMAC
		HMAC is a widely used message authentication code and a pseudorandom function generator based on cryptographic hash functions such as MD5 and SHA-1.
		HMAC is proved to be secure as long as the compression function of the underlying hash function is a pseudorandom function.
		HMAC was proved by Bellare, Canetti and Krawczyk [2] to be a PRF assuming that (1) the underlying compression function is a PRF, and (2) the iterated hash function is weakly collision-resistant.
	www.mail-archive.com /cryptography%40metzdowd.com/msg06372.html (403 words)

	DGAC
		HMAC represents shippers, carriers of all modes, container manufacturers and reconditioners, emergency response and waste clean-up companies, and a variety of other companies and trade associations involved in the field of hazardous materials transportation.
		In 1994, HMAC facilitated and submitted a consensus report from an Industry Working Group Industry Working Group on this very subject and we are most pleased to see that many of that group's recommendations have been incorporated into the current rulemaking.
		HMAC could not come to a consensus view on whether a single (flat fee) structure or a two-tier system of registration is preferable.
	www.hmac.org /comments/RSPA-99-5137.html (528 words)

	RFC 2104 (rfc2104): HMAC: Keyed-Hashing for Message Authentication - RFC Database - eLook.org
		HMAC can be used with any iterative cryptographic hash function, e.g., MD5, SHA-1, in combination with a secret shared key.
		The cryptographic strength of HMAC depends on the properties of the underlying hash function.
		This mechanism, called HMAC, is based on work by the authors [BCK1] where the construction is presented and cryptographically analyzed.
	www.elook.org /computing/rfc/rfc2104.html (245 words)

	The Use of HMAC-MD5-96 within ESP and AH
		This memo describes the use of the HMAC algorithm [2] in conjunction with the MD5 algorithm [1] as an authentication mechanism within the revised IPSEC Encapsulating Security Payload [6] and the revised IPSEC Authentication Header [7].
		If only the source and destination know the HMAC key, this provides both data origin authentication and data integrity for packets sent between the two parties; if the HMAC is correct, this proves that it must have been added by the source.
		[2] claims that HMAC does not depend upon the property of strong collision resistance, which is important to consider when evaluating the use of MD5, an algorithm which has, under recent scrutiny, been shown to be much less collision-resistant than was first thought.
	xml.resource.org /public/rfc/html/rfc2403.html (1599 words)

	HMAC (Danger API)
		HMAC is a secure hash used by SSH and SSL (and probably other protocols).
		Reset the state of this HMAC in preparation for a new computation, using the same key.
		The private key is used to generate hashes used later in the HMAC processing, but is not stored in the HMAC object directly.
	developer.danger.com /javadoc/2.0/danger/crypto/HMAC.html (453 words)

	Dr. Dobb's \| The HMAC Algorithm \| July 22, 2001
		HMAC (short for "keyed-Hashing for Message Authentication"), a variation on the MAC algorithm, has emerged as an Internet standard for a variety of applications.
		HMAC has been chosen as the mandatory-to-implement MAC for IP Security, and is used in other Internet protocols, such as Transport Layer Security (TLS, soon to replace Secure Sockets Layer) and Secure Electronic Transaction (SET).
		The appeal of HMAC is that its designers have been able to prove an exact relationship between the strength of the embedded hash function and the strength of HMAC.
	www.ddj.com /184410908;jsessionid=LH5R4I1ZKXETCQSNDLQSKHSCJUNN2JVN?_requestid=358998 (1815 words)

	sayre-http-hmac-digest-01.txt
		Sayre and Melnikov Expires October 8, 2006 [Page 4] Internet-Draft HMAC Digest Authentication April 2006 reason: The value of this directive indicates the reason for the rejection of the previous client request.
		The client applies the algorithm specified by the pw-algorithm directive to the concatenation of the username, a colon, the lowercased hexadecimal digest of the result of step 1, a colon, and the value of the realm directive.
		The client applies the HMAC construction specified by the algorithm directive to the key and the message data.
	ietfreport.isoc.org /idref/draft-sayre-http-hmac-digest (2234 words)

	[No title]
		Informational [Page 5] RFC 2104 HMAC February 1997 Given the limited confidence gained so far as for the cryptographic strength of candidate hash functions, it is important to observe the following two properties of the HMAC construction and its secure use for message authentication: 1.
		Informational [Page 6] RFC 2104 HMAC February 1997 A correct implementation of the above construction, the choice of random (or cryptographically pseudorandom) keys, a secure key exchange mechanism, frequent key refreshments, and good secrecy protection of keys are all essential ingredients for the security of the integrity verification mechanism provided by HMAC.
		Informational [Page 7] RFC 2104 HMAC February 1997 Appendix -- Sample Code For the sake of illustration we provide the following sample code for the implementation of HMAC-MD5 as well as some corresponding test vectors (the code is based on MD5 code as described in [MD5]).
	www.ietf.org /rfc/rfc2104.txt (2246 words)

	Educated Guesswork: New results on HMAC
		It turns out that many of the obvious constructions have problems and eventually one particular hash-based construction called HMAC came to dominate the space, largely based on the fact that it came with proofs of its security—assuming you made certain assumptions about the hashes it was based on.
		HMAC is used more or less everywhere these days.
		These attacks called into question the assumptions underlying the original HMAC proofs.
	educatedguesswork.org /movabletype/archives/2006/09/new_results_on.html (819 words)

	[No title]
		HMAC is a hash function based message authentication code that was designed to meet the requierments of the IPSEC working group in the IETF, and is now a standard.
		Our schemes, NMAC and HMAC, are proven to be secure as long as the underlying hash function has some reasonable cryptographic strengths.
		Java classes for various specific HMAC implementations can be found in the cryptix library.
	www-cse.ucsd.edu /users/mihir/papers/hmac.html (483 words)

	HMAC, Homepathic Medical Association of Canada
		Through the HMAC, the public is assured of a professional, ethical and qualified practitioner.
		The H.M.A.C. ensures exemplary standards of quality care by designing "Homeopathic Doctor" as part of its certification process.
		With its ongoing commitment to quality care, and because professional regulation is a matter of provincial jurisdiction, the HMAC will initiate the regulatory process through the Ministry of Health in Ontario and simultaneously on Federal level.
	www.hmac.ca (300 words)

	HMAC Grant Form Notes
		HMAC asks Friends who can afford it to consider applying for a loan for part or all of their request, in order to help stretch out the available grant money.
		HMAC particularly encourages group applications where resource persons can be brought in, thereby benefitting more than just one Friend.
		Recipients of any funds from HMAC are expected to send an account of their experiences (acknowledging HMAC as a source of funding) to The Canadian Friend as soon as possible after the activity is completed.
	www.quaker.ca /hmac/grantformnotes.html (687 words)

	HMAC
		HMACs werden in vielen modernen Protokollen wie beispielsweise TLS oder IPsec verwendet.
		Die Sicherheit des HMAC erfordert nicht zwingend kollisionsresistente Hash-Funktionen, so dass der HMAC auch auf Basis des MD5 berechnet werden kann.
		Für den HMAC kann die Sicherheit unter der Voraussetzung der Sicherheit der Hashfunktion H bewiesen werden, sofern diese eine kollisionsresistente Einweg-Funktion ist.
	www.xn--enzyklopdie-s8a.de /HMAC.html (1110 words)

	Upsilon Pi Epsilon » HMAC, The Keyed Hash-Based MAC Function
		HMAC is merely a specific type of MAC function.
		HMAC has all of the general properties of a MAC function; this means that HMAC is suitable anytime senders and receivers wish to guarantee integrity between sender and receiver.
		HMAC accomplishes both of these properties with it’s reliance on a given hash function which are both fast and return compact outputs.
	the.jhu.edu /upe/2002/01/18/hmac1-the-keyed-hash-based-mac-function (656 words)

	[No title]
		Abstract This memo describes the use of the HMAC algorithm [RFC-2104] in conjunction with the SHA-1 algorithm [FIPS-180-1] as an authentication mechanism within the revised IPSEC Encapsulating Security Payload [ESP] and the revised IPSEC Authentication Header [AH].
		Introduction This memo specifies the use of SHA-1 [FIPS-180-1] combined with HMAC [RFC-2104] as a keyed authentication mechanism within the context of the Encapsulating Security Payload and the Authentication Header.
		It is also important to consider that while SHA-1 was never developed to be used as a keyed hash algorithm, HMAC had that criteria from the onset.
	www.ietf.org /rfc/rfc2404.txt (1407 words)

	XML-Security-C: WinCAPICryptoHashHMAC Class Reference
		It relies on a seed being entered into a digest function that is then used to derive a key that can be used in an HMAC function.
		In the latter case, the HMAC function is implemented internally around a standard Windows hash function.
		In the former case, the Windows HMAC functions are used.
	xml.apache.org /security/c/apiDocs/classWinCAPICryptoHashHMAC.html (331 words)

	HMAC Class (System.Security.Cryptography) (Site not responding. Last check: 2007-10-08)
		A Hash-based Message Authentication Code (HMAC) can be used to determine whether a message sent over an insecure channel has been tampered with, provided that the sender and receiver share a secret key.
		HMAC can be used with any iterative cryptographic hash function, such as MD5 or SHA-1, in combination with a secret shared key.
		Any change to the data or the hash value results in a mismatch, because knowledge of the secret key is required to change the message and reproduce the correct hash value.
	msdn2.microsoft.com /en-US/library/system.security.cryptography.hmac(VS.80).aspx (346 words)

	userdbpw (Site not responding. Last check: 2007-10-08)
		Whether either HMAC function is actually available depends on the actual application that installs the
		Note that even though the result of HMAC hashing looks like an encrypted password, it's really not.
		Computing an intermediate HMAC context does scramble the cleartext password, however if its compromised, it WILL be possible for an attacker to succesfully authenticate.
	www.courier-mta.org /userdbpw.html (294 words)

	HMAC Digest Access Authentication for HTTP (Site not responding. Last check: 2007-10-08)
		For the HMAC Digest scheme, the value of the header is as follows:
		This directive indicates the HMAC construction to be used [1].
		This directive indicates the algorithm to be used when preparing an HMAC key.
	franklinmint.fm /2006/02/28/draft-sayre-http-hmac-digest.html (1006 words)

	Free Hmac Downloads
		It allows to calculate hash (message digest), checksum and HMAC values based on the most popular algorithms: MD2, MD4, MD5, SHA1, SHA2 (SHA256, SHA384, SHA512), RIPEMD160, PANAMA, TIGER, CRC32, ADLER32, and the hash used in eDonkey (eDonkey2000,ed2k) and eMule tools.
		HashCalc generates hash, check sum, and HMAC for files of any type which makes it a valuable utility to test for corruption your FTP and other download/upload transfers.
		The library allows to calculate hashes (message digests), checksums and HMACs for files, memory blocks, strings, blobs, streaming data.
	www.filesweb.com /hmac (278 words)

	Channel9 Wiki: GenerateHMacCode
		The HMAC serves the purpose // of validating the integrity of the original message string msg1 = text + strHmac; bool isValid = ValidateHMAC(msg1, secret); Console.Out.WriteLine("Validating MSG1 (Unaltered in transit): " + isValid.ToString()); // Test a variation of the original message with the original HMAC to test validation of the // HMAC and message.
		An HMAC consists of taking a secret known only to entities wishing to communicate, concatenating this value to the front of a message to be sent.
		Another goal in choosing a key for the HMAC process is to ensure that keys are strongly generated.
	channel9.msdn.com /wiki/default.aspx/SecurityWiki.GenerateHMacCode (595 words)

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