--- name: "md4" section: "3tcl" platform: "linux" package: "tcllib" version: "2.0+dfsg-4" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/md4/3tcl" --- # md4(3tcl) MD4 Message-Digest Algorithm ``` ``` ## NAME md4 - MD4 Message-Digest Algorithm ## SYNOPSIS package require **Tcl 8.5 9** package require **md4 ?1.0.8?** **::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. *BEWARE* The commands in this package expect binary data as their input. When a **-file** is provided then this is ensured by the commands themselves, as they open the referenced file in binary mode. When literal data, or a **-channel** are provided instead, then the command's *caller is responsible* for ensuring this fact. The necessary conversion command is **encoding convertto utf-8 $string**. *ATTENTION*, there is a *Tcl 9 COMPATIBILITY ISSUE* here. *Tcl 8.x silently mishandles* non-binary input by cutting it internally to size. I.e. by only using the low byte of a higher unicode point. No error is thrown, the *result is simply wrong*. *Tcl 9 throws an error* instead, i.e. ``` expected byte sequence but character was ... ``` ## 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. When proposing code changes, please provide *unified diffs*, i.e the output of **diff -u**. Note further that *attachments* are strongly preferred over inlined patches. Attachments can be made by going to the **Edit** form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar. ## 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 ```