sha1(n) SHA-x Message-Digest Algorithm sha1(n) 







sha1 - SHA1 Message-Digest Algorithm








package require Tcl 8.2


package require sha1 ?2.0.3?


::sha1::sha1 ?-hex|-bin? [ -channel channel |
    -file filename | string ]


::sha1::hmac key string


::sha1::hmac ?-hex|-bin? -key key [
    -channel channel | -file filename | string ]


::sha1::SHA1Init


::sha1::SHA1Update token data


::sha1::SHA1Final token


::sha1::HMACInit key


::sha1::HMACUpdate token data


::sha1::HMACFinal token












This package provides an implementation in Tcl of the SHA1
    message-digest algorithm as specified by FIPS PUB 180-1 (1). This algorithm
    takes a message and generates a 160-bit digest from the input. The SHA1
    algorithm is related to the MD4 algorithm (2) but has been strengthend
    against certain types of cryptographic attack. SHA1 should be used in
    preference to MD4 or MD5 in new applications.


This package also includes support for creating keyed
    message-digests using the HMAC algorithm from RFC 2104 (3) with SHA1 as the
    message-digest.









  
::sha1::sha1 ?-hex|-bin? [ -channel channel |
    -file filename | string ]

  
The command takes a message and returns the SHA1 digest of this message as
      a hexadecimal string. You may request the result as binary data by giving
      -bin.
    
The data to be hashed can be specified either as a string
        argument to the sha1 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. NOTE use of the
        channel or filename options results in the internal use of vwait.
        To avoid nested event loops in Tk or tclhttpd applications you should
        use the incremental programming API (see below).

    
Only one of -file, -channel or string
        should be given.

  

  
::sha1::hmac key string

  

  
::sha1::hmac ?-hex|-bin? -key key [ -channel
    channel | -file filename | string ]

  
Calculate an Hashed Message Authentication digest (HMAC) using the SHA1
      digest algorithm. HMACs are described in RFC 2104 (3) and provide an SHA1
      digest that includes a key. All options other than -key are as for
      the ::sha1::sha1 command.










For the programmer, the SHA1 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 SHA1 hash operates on a token (equivalent to the bucket).
    You call SHA1Init to obtain a token and then call SHA1Update
    as many times as required to add data to the hash. To release any resources
    and obtain the hash value, you then call SHA1Final. An equivalent set
    of functions gives you a keyed digest (HMAC).


If you have critcl and have built the tcllibc
    package then the implementation of the hashing function will be performed by
    compiled code. Failing that if you have the Trf package then this can
    be used otherwise there is a pure-tcl equivalent. The programming interface
    remains the same in all cases.



  
::sha1::SHA1Init

  
Begins a new SHA1 hash. Returns a token ID that must be used for the
      remaining functions.

  
::sha1::SHA1Update token data

  
Add data to the hash identified by token. Calling SHA1Update $token
      "abcd" is equivalent to calling SHA1Update $token
      "ab" followed by SHA1Update $token "cb".
      See EXAMPLES.

  
::sha1::SHA1Final 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 20 bytes representing the 160 bit SHA1 digest value.

  
::sha1::HMACInit key

  
This is equivalent to the ::sha1::SHA1Init command except that it
      requires the key that will be included in the HMAC.

  
::sha1::HMACUpdate token data

  

  
::sha1::HMACFinal token

  
These commands are identical to the SHA1 equivalent commands.










% sha1::sha1 "Tcl does SHA1"
285a6a91c45a9066bf39fcf24425796ef0b2a8bf



% sha1::hmac Sekret "Tcl does SHA1"
ae6251fa51b95b18cba2be95eb031d07475ff03c



% set tok [sha1::SHA1Init]
::sha1::1
% sha1::SHA1Update $tok "Tcl "
% sha1::SHA1Update $tok "does "
% sha1::SHA1Update $tok "SHA1"
% sha1::Hex [sha1::SHA1Final $tok]
285a6a91c45a9066bf39fcf24425796ef0b2a8bf










  
[1]

  
"Secure Hash Standard", National Institute of Standards and
      Technology, U.S. Department Of Commerce, April 1995.
      (http://www.itl.nist.gov/fipspubs/fip180-1.htm)

  
[2]

  
Rivest, R., "The MD4 Message Digest Algorithm", RFC 1320, MIT,
      April 1992. (http://www.rfc-editor.org/rfc/rfc1320.txt)

  
[3]

  
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)










This document, and the package it describes, will undoubtedly
    contain bugs and other problems. Please report such in the category
    sha1 of the Tcllib SF Trackers
    [http://sourceforge.net/tracker/?group_id=12883]. Please also report any
    ideas for enhancements you may have for either package and/or
  documentation.








md4, md5, ripemd128, ripemd160








FIPS 180-1, hashing, message-digest, rfc 2104, security, sha1








Hashes, checksums, and encryption








Copyright (c) 2005, Pat Thoyts <patthoyts@users.sourceforge.net>








  

    2.0.3
    sha1