NAME¶
md4 - MD4 Message-Digest Algorithm
SYNOPSIS¶
package require
Tcl 8.2
package require
md4 ?1.0?
::md4::md4 ?
-hex? [
-channel channel |
-file
filename |
string ]
::md4::hmac ?
-hex?
-key key [
-channel channel |
-file filename |
string ]
::md4::MD4Init
::md4::MD4Update token data
::md4::MD4Final token
::md4::HMACInit key
::md4::HMACUpdate token data
::md4::HMACFinal token
DESCRIPTION¶
This package is an implementation in Tcl of the MD4 message-digest algorithm as
described in RFC 1320 (1) and (2). This algorithm takes an arbitrary quantity
of data and generates a 128-bit message digest from the input. The MD4
algorithm is faster but potentially weaker than the related MD5 algorithm (3).
If you have
critcl and have built the
tcllibc package then the
implementation of the hashing function will be performed by compiled code.
Alternatively if
cryptkit is available this will be used. If no
accelerator package can be found then the pure-tcl implementation is used. The
programming interface remains the same in all cases.
COMMANDS¶
- ::md4::md4 ?-hex? [ -channel channel | -file
filename | string ]
- Calculate the MD4 digest of the data given in string. This is returned as
a binary string by default. Giving the -hex option will return a
hexadecimal encoded version of the digest.
The data to be hashed can be specified either as a string argument to the
md4 command, or as a filename or a pre-opened channel. If the
-filename argument is given then the file is opened, the data read
and hashed and the file is closed. If the -channel argument is
given then data is read from the channel until the end of file. The
channel is not closed.
Only one of -file, -channel or string should be
given.
- ::md4::hmac ?-hex? -key key [ -channel channel
| -file filename | string ]
- Calculate an Hashed Message Authentication digest (HMAC) using the MD4
digest algorithm. HMACs are described in RFC 2104 (4) and provide an MD4
digest that includes a key. All options other than -key are as for
the ::md4::md4 command.
PROGRAMMING INTERFACE¶
For the programmer, the MD4 hash can be viewed as a bucket into which one pours
data. When you have finished, you extract a value that is derived from the
data that was poured into the bucket. The programming interface to the MD4
hash operates on a token (equivalent to the bucket). You call
MD4Init
to obtain a token and then call
MD4Update as many times as required to
add data to the hash. To release any resources and obtain the hash value, you
then call
MD4Final. An equivalent set of functions gives you a keyed
digest (HMAC).
- ::md4::MD4Init
- Begins a new MD4 hash. Returns a token ID that must be used for the
remaining functions.
- ::md4::MD4Update token data
- Add data to the hash identified by token. Calling MD4Update $token
"abcd" is equivalent to calling MD4Update $token
"ab" followed by MD4Update $token "cb". See
EXAMPLES.
- ::md4::MD4Final token
- Returns the hash value and releases any resources held by this token. Once
this command completes the token will be invalid. The result is a binary
string of 16 bytes representing the 128 bit MD4 digest value.
- ::md4::HMACInit key
- This is equivalent to the ::md4::MD4Init command except that it
requires the key that will be included in the HMAC.
- ::md4::HMACUpdate token data
- ::md4::HMACFinal token
- These commands are identical to the MD4 equivalent commands.
EXAMPLES¶
% md4::md4 -hex "Tcl does MD4"
858da9b31f57648a032230447bd15f25
% md4::hmac -hex -key Sekret "Tcl does MD4"
c324088e5752872689caedf2a0464758
% set tok [md4::MD4Init]
::md4::1
% md4::MD4Update $tok "Tcl "
% md4::MD4Update $tok "does "
% md4::MD4Update $tok "MD4"
% md4::Hex [md4::MD4Final $tok]
858da9b31f57648a032230447bd15f25
REFERENCES¶
- [1]
- Rivest, R., "The MD4 Message Digest Algorithm", RFC 1320, MIT,
April 1992. ( http://www.rfc-editor.org/rfc/rfc1320.txt)
- [2]
- Rivest, R., "The MD4 message digest algorithm", in A.J. Menezes
and S.A. Vanstone, editors, Advances in Cryptology - CRYPTO '90
Proceedings, pages 303-311, Springer-Verlag, 1991.
- [3]
- Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, MIT
and RSA Data Security, Inc, April 1992. (
http://www.rfc-editor.org/rfc/rfc1321.txt)
- [4]
- Krawczyk, H., Bellare, M. and Canetti, R. "HMAC: Keyed-Hashing for
Message Authentication", RFC 2104, February 1997. (
http://www.rfc-editor.org/rfc/rfc2104.txt)
BUGS, IDEAS, FEEDBACK¶
This document, and the package it describes, will undoubtedly contain bugs and
other problems. Please report such in the category
md4 of the
Tcllib
Trackers [
http://core.tcl.tk/tcllib/reportlist]. Please also report any
ideas for enhancements you may have for either package and/or documentation.
SEE ALSO¶
md5, sha1
KEYWORDS¶
hashing, md4, message-digest, rfc 1320, rfc 1321, rfc 2104, security
CATEGORY¶
Hashes, checksums, and encryption
COPYRIGHT¶
Copyright (c) 2003, Pat Thoyts <patthoyts@users.sourceforge.net>