1rskeygen(1)                 General Commands Manual                rskeygen(1)
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NAME

6       rskeygen - generate private key pairs for TI graphing calculators
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SYNOPSIS

10       rskeygen [ --secure ] [ --ti ] [ --length nbytes ]
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DESCRIPTION

14       rskeygen  generates  application  and OS signing keys for the Texas In‐
15       struments TI-73, TI-83 Plus, TI-84 Plus, TI-89, and TI-92 Plus graphing
16       calculators.   These  keys consist of two prime numbers p and q as well
17       as their product n.  Current calculator models impose a  limit  of  512
18       bits  (64  bytes)  on the size of n, so p and q are generally about 256
19       bits each.  As of this writing this means factoring  n  is  beyond  the
20       reach  of  most  people, though this will undoubtedly change in the fu‐
21       ture.
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23       The keys generated by rskeygen are not very useful at the  moment,  be‐
24       cause  in order for an application or OS to be accepted by the calcula‐
25       tor, the key used to sign it must itself be signed using  the  calcula‐
26       tor's  own  (possibly  unique)  private key, which is only known to TI.
27       Nevertheless, rskeygen is provided in the hope that it can  be  useful,
28       both for testing and for devising new signature schemes based on TI's.
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31   OPTIONS
32       --secure
33              Attempt  to generate a ``secure'' key using the system's entropy
34              pool, /dev/random (see random(4).)  The actual security is  thus
35              dependent on your system's implementation of /dev/random.
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37              Without  --secure,  the  keys are generated based on the current
38              time and process ID, which is not secure in the slightest.
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41       --ti   Generate keys which are palatable to TI's official  app  signing
42              programs.   This forces p to be congruent to 3 and q to 7 modulo
43              8.  This option is not necessary when using  rabbitsign(1),  nor
44              is  it necessary for the calculator to validate signatures prop‐
45              erly.
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48       --length nbytes
49              Specify the length in bytes of the modulus n; p and q  are  each
50              calculated  to  be  approximately half this length.  This should
51              not be greater than 64 for current calculators, and must be less
52              than  256  in any event due to a limitation of the key file for‐
53              mat.
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SEE ALSO

57       rabbitsign(1), packxxk(1)
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AUTHOR

61       Benjamin Moody <floppusmaximus@users.sf.net>
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65RabbitSign 2.0                     July 2009                       rskeygen(1)