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 ?2.0.4?
14 ::sha1::sha1 ?-hex|-bin? [ -channel channel | -file filename | ?--?
16 string ]
17 ::sha1::hmac key string
19 ::sha1::hmac ?-hex|-bin? -key key [ -channel channel | -file filename |
21 ?--? string ]
22 ::sha1::SHA1Init
24 ::sha1::SHA1Update token data
26 ::sha1::SHA1Final token
28 ::sha1::HMACInit key
30 ::sha1::HMACUpdate token data
32 ::sha1::HMACFinal token
34______________________________________________________________________________
36
38 This package provides an implementation in Tcl of the SHA1 message-di‐
39 gest algorithm as specified by FIPS PUB 180-1 (1). This algorithm takes
40 a message and generates a 160-bit digest from the input. The SHA1 algo‐
41 rithm is related to the MD4 algorithm (2) but has been strengthend
42 against certain types of cryptographic attack. SHA1 should be used in
43 preference to MD4 or MD5 in new applications.
44 This package also includes support for creating keyed message-digests
46 using the HMAC algorithm from RFC 2104 (3) with SHA1 as the message-di‐
47 gest.
48
50 ::sha1::sha1 ?-hex|-bin? [ -channel channel | -file filename | ?--?
51 string ]
52 The command takes a message and returns the SHA1 digest of this
53 message as a hexadecimal string. You may request the result as
54 binary data by giving -bin.
55 The data to be hashed can be specified either as a string argu‐
57 ment to the sha1 command, or as a filename or a pre-opened chan‐
58 nel. If the -filename argument is given then the file is opened,
59 the data read and hashed and the file is closed. If the -channel
60 argument is given then data is read from the channel until the
61 end of file. The channel is not closed. NOTE use of the channel
62 or filename options results in the internal use of vwait. To
63 avoid nested event loops in Tk or tclhttpd applications you
64 should use the incremental programming API (see below).
65 Only one of -file, -channel or string should be given.
67 If the string to hash can be mistaken for an option (leading
69 dash "-"), use the option -- before it to terminate option pro‐
70 cessing and force interpretation as a string.
71 ::sha1::hmac key string
73 ::sha1::hmac ?-hex|-bin? -key key [ -channel channel | -file filename |
75 ?--? string ]
76 Calculate an Hashed Message Authentication digest (HMAC) using
77 the SHA1 digest algorithm. HMACs are described in RFC 2104 (3)
78 and provide an SHA1 digest that includes a key. All options
79 other than -key are as for the ::sha1::sha1 command.
80 If the string to hash can be mistaken for an option (leading
82 dash "-"), use the option -- before it to terminate option pro‐
83 cessing and force interpretation as a string.
84
86 For the programmer, the SHA1 hash can be viewed as a bucket into which
87 one pours data. When you have finished, you extract a value that is de‐
88 rived from the data that was poured into the bucket. The programming
89 interface to the SHA1 hash operates on a token (equivalent to the
90 bucket). You call SHA1Init to obtain a token and then call SHA1Update
91 as many times as required to add data to the hash. To release any re‐
92 sources and obtain the hash value, you then call SHA1Final. An equiva‐
93 lent set of functions gives you a keyed digest (HMAC).
94 If you have critcl and have built the tcllibc package then the imple‐
96 mentation of the hashing function will be performed by compiled code.
97 Failing that if you have the Trf package then this can be used other‐
98 wise there is a pure-tcl equivalent. The programming interface remains
99 the same in all cases.
100 ::sha1::SHA1Init
102 Begins a new SHA1 hash. Returns a token ID that must be used for
103 the remaining functions.
104 ::sha1::SHA1Update token data
106 Add data to the hash identified by token. Calling SHA1Update
107 $token "abcd" is equivalent to calling SHA1Update $token "ab"
108 followed by SHA1Update $token "cb". See EXAMPLES.
109 ::sha1::SHA1Final token
111 Returns the hash value and releases any resources held by this
112 token. Once this command completes the token will be invalid.
113 The result is a binary string of 20 bytes representing the 160
114 bit SHA1 digest value.
115 ::sha1::HMACInit key
117 This is equivalent to the ::sha1::SHA1Init command except that
118 it requires the key that will be included in the HMAC.
119 ::sha1::HMACUpdate token data
121 ::sha1::HMACFinal token
123 These commands are identical to the SHA1 equivalent commands.
124
126 % sha1::sha1 "Tcl does SHA1"
127 285a6a91c45a9066bf39fcf24425796ef0b2a8bf
128 % sha1::hmac Sekret "Tcl does SHA1"
132 ae6251fa51b95b18cba2be95eb031d07475ff03c
133 % set tok [sha1::SHA1Init]
137 ::sha1::1
138 % sha1::SHA1Update $tok "Tcl "
139 % sha1::SHA1Update $tok "does "
140 % sha1::SHA1Update $tok "SHA1"
141 % sha1::Hex [sha1::SHA1Final $tok]
142 285a6a91c45a9066bf39fcf24425796ef0b2a8bf
143
146 [1] "Secure Hash Standard", National Institute of Standards and
147 Technology, U.S. Department Of Commerce, April 1995.
148 (http://www.itl.nist.gov/fipspubs/fip180-1.htm)
149 [2] Rivest, R., "The MD4 Message Digest Algorithm", RFC 1320, MIT,
151 April 1992. (http://www.rfc-editor.org/rfc/rfc1320.txt)
152 [3] Krawczyk, H., Bellare, M. and Canetti, R. "HMAC: Keyed-Hashing
154 for Message Authentication", RFC 2104, February 1997.
155 (http://www.rfc-editor.org/rfc/rfc2104.txt)
156
158 This document, and the package it describes, will undoubtedly contain
159 bugs and other problems. Please report such in the category sha1 of
160 the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please
161 also report any ideas for enhancements you may have for either package
162 and/or documentation.
163 When proposing code changes, please provide unified diffs, i.e the out‐
165 put of diff -u.
166 Note further that attachments are strongly preferred over inlined
168 patches. Attachments can be made by going to the Edit form of the
169 ticket immediately after its creation, and then using the left-most
170 button in the secondary navigation bar.
171
173 md4, md5, ripemd128, ripemd160
174
176 FIPS 180-1, hashing, message-digest, rfc 2104, security, sha1
177
179 Hashes, checksums, and encryption
180
182 Copyright (c) 2005, Pat Thoyts <patthoyts@users.sourceforge.net>
183tcllib 2.0.4 sha1(n)