1sha1(n) SHA-x Message-Digest Algorithm sha1(n)
2______________________________________________________________________________
6
8 sha1 - SHA1 Message-Digest Algorithm
9
11 package require Tcl 8.2
12 package require sha1 ?2.0.3?
14 ::sha1::sha1 ?-hex|-bin? [ -channel channel | -file filename | string ]
16 ::sha1::hmac key string
18 ::sha1::hmac ?-hex|-bin? -key key [ -channel channel | -file filename |
20 string ]
21 ::sha1::SHA1Init
23 ::sha1::SHA1Update token data
25 ::sha1::SHA1Final token
27 ::sha1::HMACInit key
29 ::sha1::HMACUpdate token data
31 ::sha1::HMACFinal token
33_________________________________________________________________
35
37 This package provides an implementation in Tcl of the SHA1 message-
38 digest algorithm as specified by FIPS PUB 180-1 (1). This algorithm
39 takes a message and generates a 160-bit digest from the input. The SHA1
40 algorithm is related to the MD4 algorithm (2) but has been strengthend
41 against certain types of cryptographic attack. SHA1 should be used in
42 preference to MD4 or MD5 in new applications.
43 This package also includes support for creating keyed message-digests
45 using the HMAC algorithm from RFC 2104 (3) with SHA1 as the message-
46 digest.
47
49 ::sha1::sha1 ?-hex|-bin? [ -channel channel | -file filename | string ]
50 The command takes a message and returns the SHA1 digest of this
51 message as a hexadecimal string. You may request the result as
52 binary data by giving -bin.
53 The data to be hashed can be specified either as a string argu‐
55 ment to the sha1 command, or as a filename or a pre-opened chan‐
56 nel. If the -filename argument is given then the file is opened,
57 the data read and hashed and the file is closed. If the -channel
58 argument is given then data is read from the channel until the
59 end of file. The channel is not closed. NOTE use of the channel
60 or filename options results in the internal use of vwait. To
61 avoid nested event loops in Tk or tclhttpd applications you
62 should use the incremental programming API (see below).
63 Only one of -file, -channel or string should be given.
65 ::sha1::hmac key string
67 ::sha1::hmac ?-hex|-bin? -key key [ -channel channel | -file filename |
69 string ]
70 Calculate an Hashed Message Authentication digest (HMAC) using
71 the SHA1 digest algorithm. HMACs are described in RFC 2104 (3)
72 and provide an SHA1 digest that includes a key. All options
73 other than -key are as for the ::sha1::sha1 command.
74
76 For the programmer, the SHA1 hash can be viewed as a bucket into which
77 one pours data. When you have finished, you extract a value that is
78 derived from the data that was poured into the bucket. The programming
79 interface to the SHA1 hash operates on a token (equivalent to the
80 bucket). You call SHA1Init to obtain a token and then call SHA1Update
81 as many times as required to add data to the hash. To release any
82 resources and obtain the hash value, you then call SHA1Final. An equiv‐
83 alent set of functions gives you a keyed digest (HMAC).
84 If you have critcl and have built the tcllibc package then the imple‐
86 mentation of the hashing function will be performed by compiled code.
87 Failing that if you have the Trf package then this can be used other‐
88 wise there is a pure-tcl equivalent. The programming interface remains
89 the same in all cases.
90 ::sha1::SHA1Init
92 Begins a new SHA1 hash. Returns a token ID that must be used for
93 the remaining functions.
94 ::sha1::SHA1Update token data
96 Add data to the hash identified by token. Calling SHA1Update
97 $token "abcd" is equivalent to calling SHA1Update $token "ab"
98 followed by SHA1Update $token "cb". See EXAMPLES.
99 ::sha1::SHA1Final token
101 Returns the hash value and releases any resources held by this
102 token. Once this command completes the token will be invalid.
103 The result is a binary string of 20 bytes representing the 160
104 bit SHA1 digest value.
105 ::sha1::HMACInit key
107 This is equivalent to the ::sha1::SHA1Init command except that
108 it requires the key that will be included in the HMAC.
109 ::sha1::HMACUpdate token data
111 ::sha1::HMACFinal token
113 These commands are identical to the SHA1 equivalent commands.
114
116 % sha1::sha1 "Tcl does SHA1"
117 285a6a91c45a9066bf39fcf24425796ef0b2a8bf
118 % sha1::hmac Sekret "Tcl does SHA1"
121 ae6251fa51b95b18cba2be95eb031d07475ff03c
122 % set tok [sha1::SHA1Init]
125 ::sha1::1
126 % sha1::SHA1Update $tok "Tcl "
127 % sha1::SHA1Update $tok "does "
128 % sha1::SHA1Update $tok "SHA1"
129 % sha1::Hex [sha1::SHA1Final $tok]
130 285a6a91c45a9066bf39fcf24425796ef0b2a8bf
131
134 [1] "Secure Hash Standard", National Institute of Standards and
135 Technology, U.S. Department Of Commerce, April 1995.
136 (http://www.itl.nist.gov/fipspubs/fip180-1.htm)
137 [2] Rivest, R., "The MD4 Message Digest Algorithm", RFC 1320, MIT,
139 April 1992. (http://www.rfc-editor.org/rfc/rfc1320.txt)
140 [3] Krawczyk, H., Bellare, M. and Canetti, R. "HMAC: Keyed-Hashing
142 for Message Authentication", RFC 2104, February 1997.
143 (http://www.rfc-editor.org/rfc/rfc2104.txt)
144
146 This document, and the package it describes, will undoubtedly contain
147 bugs and other problems. Please report such in the category sha1 of
148 the Tcllib SF Trackers [http://source‐
149 forge.net/tracker/?group_id=12883]. Please also report any ideas for
150 enhancements you may have for either package and/or documentation.
151
153 md4, md5, ripemd128, ripemd160
154
156 FIPS 180-1, hashing, message-digest, rfc 2104, security, sha1
157
159 Copyright (c) 2005, Pat Thoyts <patthoyts@users.sourceforge.net>
160sha1 2.0.3 sha1(n)