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Revision 1.1 by root, Sat Sep 6 22:10:54 2003 UTC vs.
Revision 1.2 by root, Wed Jul 14 15:55:44 2004 UTC

… …
12 $crypted = $cipher->encrypt($plaintext); 12 $crypted = $cipher->encrypt($plaintext);
13 # - OR - 13 # - OR -
14 $plaintext = $cipher->decrypt($crypted); 14 $plaintext = $cipher->decrypt($crypted);
15 15
16DESCRIPTION 16DESCRIPTION
17 This module implements thw twofish cipher in a less braindamaged (read: 17 This module implements the twofish cipher in a less braindamaged (read:
18 slow and ugly) way than the existing "Crypt::Twofish" module. 18 slow and ugly) way than the existing "Crypt::Twofish" module.
19 19
20 Although it is "Crypt::CBC" compliant you usually gain nothing by using 20 Although it is "Crypt::CBC" compliant you usually gain nothing by using
21 that module (except generality), since "Crypt::Twofish2" can work in 21 that module (except generality, which is often a good thing), since
22 either ECB or CBC mode. 22 "Crypt::Twofish2" can work in either ECB or CBC mode itself.
23 23
24 keysize 24 keysize
25 Returns the keysize, which is 32 (bytes). The Twofish2 cipher 25 Returns the keysize, which is 32 (bytes). The Twofish2 cipher
26 actually supports keylengths of 16, 24 or 32 bytes, but there is no 26 actually supports keylengths of 16, 24 or 32 bytes, but there is no
27 way to communicate this to "Crypt::CBC". 27 way to communicate this to "Crypt::CBC".
… …
30 The blocksize for Twofish2 is 16 bytes (128 bits), which is somewhat 30 The blocksize for Twofish2 is 16 bytes (128 bits), which is somewhat
31 unique. It is also the reason I need this module myself ;) 31 unique. It is also the reason I need this module myself ;)
32 32
33 $cipher = new $key [, $mode] 33 $cipher = new $key [, $mode]
34 Create a new "Crypt::Twofish2" cipher object with the given key 34 Create a new "Crypt::Twofish2" cipher object with the given key
35 (which must be 128, 192 or 256 bits long). The additional "$mode" 35 (which must be 128, 192 or 256 bits long). The additional $mode
36 argument is the encryption mode, either "MODE_ECB" (electronic 36 argument is the encryption mode, either "MODE_ECB" (electronic
37 cookbook mode, the default), "MODE_CBC" (cipher block chaining, the 37 cookbook mode, the default), "MODE_CBC" (cipher block chaining, the
38 same that "Crypt::CBC" does) or "MODE_CFB1" (1-bit cipher feedback 38 same that "Crypt::CBC" does) or "MODE_CFB1" (1-bit cipher feedback
39 mode). 39 mode).
40 40
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53 53
54 The "MODE_*"-constants are not exported by this module, so you must 54 The "MODE_*"-constants are not exported by this module, so you must
55 specify them as "Crypt::Twofish2::MODE_CBC" etc. (sorry for that). 55 specify them as "Crypt::Twofish2::MODE_CBC" etc. (sorry for that).
56 56
57 $cipher->encrypt($data) 57 $cipher->encrypt($data)
58 Encrypt data. The size of "$data" must be a multiple of "blocksize" 58 Encrypt data. The size of $data must be a multiple of "blocksize"
59 (16 bytes), otherwise this function will croak. Apart from that, it 59 (16 bytes), otherwise this function will croak. Apart from that, it
60 can be of (almost) any length. 60 can be of (almost) any length.
61 61
62 $cipher->decrypt($data) 62 $cipher->decrypt($data)
63 The pendant to "encrypt" in that it *de*crypts data again. 63 The pendant to "encrypt" in that it *de*crypts data again.
64 64
65SEE ALSO 65SEE ALSO
66 the Crypt::CBC manpage, the Crypt::Twofish manpage. 66 Crypt::CBC, Crypt::Twofish.
67 67
68BUGS 68BUGS
69 Should EXPORT or EXPORT_OK the MODE constants. 69 Should EXPORT or EXPORT_OK the MODE constants.
70
71 The testsuite does not check wether the encrypted valued are correct.
72 70
73 There should be a way to access initial IV contents :( 71 There should be a way to access initial IV contents :(
74 72
75 Although I tried to make the original twofish code portable, I can't say 73 Although I tried to make the original twofish code portable, I can't say
76 how much I did succeed. The code tries to be portable itself, and I hope 74 how much I did succeed. The code tries to be portable itself, and I hope
77 I got the endianness issues right. The code is also copyright 75 I got the endianness issues right. The code is also copyright
78 Counterpane Systems, no license accompanied it, so using it might 76 Counterpane Systems, no license accompanied it, so using it might
79 actually be illegal ;) 77 actually be illegal ;)
80 78
79 I also cannot guarantee for security, but the module is used quite a
80 bit, so there are no obvious bugs left.
81
81AUTHOR 82AUTHOR
82 Marc Lehmann <pcg@goof.com> 83 Marc Lehmann <pcg@goof.com>
83 http://www.goof.com/pcg/marc/ 84 http://www.goof.com/pcg/marc/
84 85
85 The actualy twofish encryption is written in horribly microsoft'ish looking 86 The actual twofish encryption is written in horribly microsoft'ish looking
86 almost ansi-c by Doug Whiting. 87 almost ansi-c by Doug Whiting.
87 88

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