MD4 hash - Revision history

Vollstrecker: Language Link and switched to a numbered List

2007-09-03T15:13:37Z

Language Link and switched to a numbered List

85.65.246.185: ed2k hash algorithm

2007-05-07T07:07:58Z

ed2k hash algorithm

Colin: reword

2006-12-28T20:28:54Z

reword

195.3.81.25 at 09:14, 28 December 2006

2006-12-28T09:14:01Z

62.82.143.103 at 10:18, 14 January 2006

2006-01-14T10:18:56Z

204.186.210.188: MD4 security update

2006-01-14T07:06:24Z

MD4 security update

Jacobo221 at 22:12, 13 December 2005

2005-12-13T22:12:17Z

Jacobo221 at 22:12, 13 December 2005

2005-12-13T22:12:08Z

Jacobo221 at 22:09, 13 December 2005

2005-12-13T22:09:49Z

203.217.56.128 at 12:56, 1 December 2005

2005-12-01T12:56:34Z

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 An '''MD4 hash''' is a unique value produced by a mathematical calculation. It provides a 128-bit (16 [[byte]]s, 32 hex chars) key from the data input which is claimed to be unique. As such, MD4 hashes are used to ensure data integrity.
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 Important note! although ed2k hash is based on MD4, it is '''not''' MD4. the algorithm for computing ed2k hash is as follows:
-. split the file into blocks of 9728000 bytes
+# split the file into blocks of 9728000 bytes
-. compute MD4 hash digest of each file block separately
+# compute MD4 hash digest of each file block separately
-. concatenate the list of block digests into one big byte array
+# concatenate the list of block digests into one big byte array
-. compute MD4 of array created in step #3. this is the ed2k hash.
+# compute MD4 of array created in step #3. this is the ed2k hash.
 MD4 was developed by MIT professor Ronald L. Rivest. It was accepted by the RSA in October 1990.

← Older revision		Revision as of 07:07, 7 May 2007
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	[[aMule]] uses MD4 hashes to ensure that no transmission errors corrupt in the files you share. Its MD4 algorithm is based on [[libcrypto\|Crypto++]].		[[aMule]] uses MD4 hashes to ensure that no transmission errors corrupt in the files you share. Its MD4 algorithm is based on [[libcrypto\|Crypto++]].
		+
		+	Important note! although ed2k hash is based on MD4, it is '''not''' MD4. the algorithm for computing ed2k hash is as follows:
		+	1. split the file into blocks of 9728000 bytes
		+	2. compute MD4 hash digest of each file block separately
		+	3. concatenate the list of block digests into one big byte array
		+	4. compute MD4 of array created in step #3. this is the ed2k hash.

	MD4 was developed by MIT professor Ronald L. Rivest. It was accepted by the RSA in October 1990.		MD4 was developed by MIT professor Ronald L. Rivest. It was accepted by the RSA in October 1990.

@@ Line 1: / Line 1: @@
-An [http://www.faqs.org/rfcs/rfc1320.html MD4] hash is a unique value given as a result of a mathematical expression following the [http://www.faqs.org/rfcs/rfc1320.html MD4 algorithm] which claims to ensure data integrity.<br>
+An '''MD4 hash''' is a unique value produced by a mathematical calculation. It provides a 128-bit (16 [[byte]]s, 32 hex chars) key from the data input which is claimed to be unique. As such, MD4 hashes are used to ensure data integrity.
-It provides a 128-bit (16 [[byte]]s, 32 hex chars) message digest from the data input (the input may be of any length) that is claimed to be unique.
-[http://www.faqs.org/rfcs/rfc1320.html MD4] was developed by [http://theory.lcs.mit.edu/~rivest Professor Ronald L. Rivest] of [http://web.mit.edu MIT] and accepted by the [http://www.rsa.com RSA] on [http://www.faqs.org/rfcs/rfc1186.html October 1990] and then redesigned on [http://www.faqs.org/rfcs/rfc1320.html April 1992].
+[[aMule]] uses MD4 hashes to ensure that no transmission errors corrupt in the files you share. Its MD4 algorithm is based on [[libcrypto|Crypto++]].
-Both [http://www.faqs.org/rfcs/rfc1320.html MD4] and its successor [http://userpages.umbc.edu/~mabzug1/cs/md5/md5.html MD5] (which is an extension of [http://www.faqs.org/rfcs/rfc1320.html MD4]) are optimized for 32-bit machines, while its predecessor [http://www.faqs.org/rfcs/rfc1319.html MD2] was optimized for 8-bit machines.
+MD4 was developed by MIT professor Ronald L. Rivest. It was accepted by the RSA in October 1990.
-[http://www.faqs.org/rfcs/rfc1320.html MD4] is known to be fast, but possibly not absolutely secure. On the other hand, [http://userpages.umbc.edu/~mabzug1/cs/md5/md5.html MD5] is not as fast as the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm, but offers much more assurance of data security.
+Both MD4, and its successor MD5, are optimized for 32-bit machines. Its predecessor MD2 was optimized for 8-bit machines. MD4 is known to be fast, but possibly not absolutely secure. On the other hand, MD5  is not as fast as MD4 but offers much more assurance of data security.
+==External links==
-[[aMule]] incorporates the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm based on the [[libcrypto|Crypto++]]'s library sources (in some beta [[aMule]] v2 releases, it did actually use [[libcrypto|Crypto++]]).
+* [http://www.faqs.org/rfcs/rfc1186.html RFC 1186: MD4]
+* [http://www.faqs.org/rfcs/rfc1319.html RFC 1319: MD2]
-NOTE : the hash used in ed2k protocol URLs in NOT MD4 !!!
+* [http://www.faqs.org/rfcs/rfc1320.html RFC 1320: MD4]
-It is similar but not the same. Above certain filesize (the exact value is documented somewhere) the MD4 and the ed2k hash for the same data are not the same. Anybody can check this by computing a hash of any file greater than 15 megabytes using any hash tool, like HashCalc, fsum etc.
+* [http://theory.lcs.mit.edu/~rivest Home page of Ronald L. Rivest]

← Older revision		Revision as of 09:14, 28 December 2006
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	[[aMule]] incorporates the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm based on the [[libcrypto\|Crypto++]]'s library sources (in some beta [[aMule]] v2 releases, it did actually use [[libcrypto\|Crypto++]]).		[[aMule]] incorporates the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm based on the [[libcrypto\|Crypto++]]'s library sources (in some beta [[aMule]] v2 releases, it did actually use [[libcrypto\|Crypto++]]).
		+
		+	NOTE : the hash used in ed2k protocol URLs in NOT MD4 !!!
		+	It is similar but not the same. Above certain filesize (the exact value is documented somewhere) the MD4 and the ed2k hash for the same data are not the same. Anybody can check this by computing a hash of any file greater than 15 megabytes using any hash tool, like HashCalc, fsum etc.

@@ Line 7: / Line 7: @@
 [http://www.faqs.org/rfcs/rfc1320.html MD4] is known to be fast, but possibly not absolutely secure. On the other hand, [http://userpages.umbc.edu/~mabzug1/cs/md5/md5.html MD5] is not as fast as the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm, but offers much more assurance of data security.
-: This is a bit out of date, or just uninformed. MD5 is questionable, these days (the currently existing attacks on it aren't serious for most applications, but the door is open for more), and MD4 is known to be absolutely hopeless, and collisions can be found with very little in the way of computational effort. The upshot of which is that it would be theoretically pretty easy for a rogue node to cause undetectable corruption to files on ed2k.
 [[aMule]] incorporates the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm based on the [[libcrypto|Crypto++]]'s library sources (in some beta [[aMule]] v2 releases, it did actually use [[libcrypto|Crypto++]]).

← Older revision		Revision as of 07:06, 14 January 2006
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	[http://www.faqs.org/rfcs/rfc1320.html MD4] is known to be fast, but possibly not absolutely secure. On the other hand, [http://userpages.umbc.edu/~mabzug1/cs/md5/md5.html MD5] is not as fast as the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm, but offers much more assurance of data security.		[http://www.faqs.org/rfcs/rfc1320.html MD4] is known to be fast, but possibly not absolutely secure. On the other hand, [http://userpages.umbc.edu/~mabzug1/cs/md5/md5.html MD5] is not as fast as the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm, but offers much more assurance of data security.
		+	: This is a bit out of date, or just uninformed. MD5 is questionable, these days (the currently existing attacks on it aren't serious for most applications, but the door is open for more), and MD4 is known to be absolutely hopeless, and collisions can be found with very little in the way of computational effort. The upshot of which is that it would be theoretically pretty easy for a rogue node to cause undetectable corruption to files on ed2k.

	[[aMule]] incorporates the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm based on the [[libcrypto\|Crypto++]]'s library sources (in some beta [[aMule]] v2 releases, it did actually use [[libcrypto\|Crypto++]]).		[[aMule]] incorporates the [http://www.faqs.org/rfcs/rfc1320.html MD4] algorithm based on the [[libcrypto\|Crypto++]]'s library sources (in some beta [[aMule]] v2 releases, it did actually use [[libcrypto\|Crypto++]]).