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Revision 1.1 by root, Sat Sep 6 22:12:00 2003 UTC vs.
Revision 1.4 by root, Tue Jul 21 05:01:01 2015 UTC

… …
11 11
12 One thing to note about this module is that it requires ISO C99 support, 12 One thing to note about this module is that it requires ISO C99 support,
13 both in your compiler and your standard library. If you don't have a 13 both in your compiler and your standard library. If you don't have a
14 compiler that supports ISO C, get gcc at http://gcc.gnu.org/ :) 14 compiler that supports ISO C, get gcc at http://gcc.gnu.org/ :)
15 15
16 $cipher = new [param => value...] 16 $secs = estimate_time $size
17 Estimate the average time necessary to calculate a token of the
18 given size.
17 19
18 size => 20 + some 20 See also "estimate_size".
21
22 $size = estimate_size $time[, $min]
23 Estimate the size that can be calculated in the given time (which is
24 an upper bound). The function will not return a size less then
25 "min".
26
27 Estimating the time to be used can go wrong by as much as 50% (but
28 is usually quite accurate), and the estimation itself can take as
29 much as a second on slower (<pentium) machines, but faster machines
30 (1Ghz P3 for example) usually handle it within a hundredth of a
31 second or so.
32
33 The estimation will be done only once, so you can call this fucntion
34 as often as you like without incuring the overhead everytime.
35
36 $cipher = new Digest::Hashcash [param => value...]
37
38 size => 18
19 The number of collisions, in bits. Every bit increases the time 39 The number of collisions, in bits. Every bit increases the time
20 to create the token (and thus the cash) by two. 40 to create the token (and thus the cash) by two.
21 41
22 uid => "" 42 uid => ""
23 A string used to make the token more unique (e.g. the senders 43 A string used to make the token more unique (e.g. the senders
… …
35 55
36 timestamp => 0 56 timestamp => 0
37 The timestamp to use. A value of 0 (the default) means to use 57 The timestamp to use. A value of 0 (the default) means to use
38 the current time. 58 the current time.
39 59
40 $token = $cipher->hash($data [, param => value...]) 60 $token = $cipher->hash ($data [, param => value...])
41 Creates and returns a new token. This can take some time. 61 Creates and returns a new token. This can take some time.
42 62
43 Any additional parameters are interpreted the same way as arguments 63 Any additional parameters are interpreted the same way as arguments
44 to "new". 64 to "new".
45 65
46 $prefix = $cipher->verify($token [, param => value...])) 66 $prefix = $cipher->verify ($token [, param => value...]))
47 Checks the given token and returns true if the token has the minimum 67 Checks the given token and returns true if the token has the minimum
48 number of prefix bits, or false otherwise. The value returned is 68 number of prefix bits, or false otherwise. The value returned is
49 actually the number of collisions, so to find the number of 69 actually the number of collisions, so to find the number of
50 collisions bits specify "collisions => 0". 70 collisions bits specify "collisions => 0".
51 71
52 Any additional parameters are interpreted the same way as arguments 72 Any additional parameters are interpreted the same way as arguments
53 to "new". 73 to "new".
54 74
55 $resource = $cipher->resource($token) 75 $resource = $cipher->resource ($token)
56 Returns the resource part, or "undef". 76 Returns the resource part, or "undef".
57 77
58 $tstamp = $ciper->timestamp($token) 78 $tstamp = $ciper->timestamp ($token)
59 Returns the timestamp part (in the same format as perl's "time"), or 79 Returns the timestamp part (in the same format as perl's "time"), or
60 "undef". 80 "undef".
61 81
62SEE ALSO 82SEE ALSO
63 <http://www.hashcash.org>. 83 <http://www.hashcash.org>.
64 84
85SUPPORT FOR THE PERL MULTICORE SPECIFICATION
86 This module supports the perl multicore specification
87 (<http://perlmulticore.schmorp.de/>) for token generation of any length
88 and size.
89
65BUGS 90BUGS
66 * There is a y2k+100 problem, as I always assume the same as Time::Local. 91 * There is a y2k+100 problem, as I always assume the same as Time::Local.
67 This is a problem with the hashcash specification, which specifies 92 This is a problem with the hashcash specification, which specifies
68 yeras as 2 digits :( 93 years as 2 digits :(
69 94
70AUTHOR 95AUTHOR
71 Marc Lehmann <pcg@goof.com> 96 Marc Lehmann <schmorp@schmorp.de>
72 http://home.schmorp.de 97 http://home.schmorp.de
73 98

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