Re: RC2ParameterVersion in example 6.3

["Jacoby, Jeffrey" <jjacoby@xxxxxxxxxxxxxxx>]

Paul Hoffman / IMC wrote:
> 
> At 8:40 PM -0700 5/2/03, Blake Ramsdell wrote:
> >Example 6.3 in examples-10 states that the example is "Basic encrypted
> >content, RC2/40 and RSA".  The RC2 parameter value is:
> >
> >  248 02    1:             INTEGER 58
> >
> >Which I believe corresponds to a 128-bit effective key length, not a
> >40-bit effective key length.
> 
> Man, we went through this a zillion times when we writing S/MIME v2.
> Could someone verify this for me? I'm happy changing the title of the
> example, but don't want to fall into the same hole we have in the
> past.


Here is cut-and-pasted copy of the EKB-version table from RFC2268
(you'll need a monospaced-font to see this right):

        0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f

   00: bd 56 ea f2 a2 f1 ac 2a b0 93 d1 9c 1b 33 fd d0
   10: 30 04 b6 dc 7d df 32 4b f7 cb 45 9b 31 bb 21 5a
   20: 41 9f e1 d9 4a 4d 9e da a0 68 2c c3 27 5f 80 36
   30: 3e ee fb 95 1a fe ce a8 34 a9 13 f0 a6 3f d8 0c
   40: 78 24 af 23 52 c1 67 17 f5 66 90 e7 e8 07 b8 60
   50: 48 e6 1e 53 f3 92 a4 72 8c 08 15 6e 86 00 84 fa
   60: f4 7f 8a 42 19 f6 db cd 14 8d 50 12 ba 3c 06 4e
   70: ec b3 35 11 a1 88 8e 2b 94 99 b7 71 74 d3 e4 bf
   80: 3a de 96 0e bc 0a ed 77 fc 37 6b 03 79 89 62 c6
   90: d7 c0 d2 7c 6a 8b 22 a3 5b 05 5d 02 75 d5 61 e3
   a0: 18 8f 55 51 ad 1f 0b 5e 85 e5 c2 57 63 ca 3d 6c
   b0: b4 c5 cc 70 b2 91 59 0d 47 20 c8 4f 58 e0 01 e2
   c0: 16 38 c4 6f 3b 0f 65 46 be 7e 2d 7b 82 f9 40 b5
   d0: 1d 73 f8 eb 26 c7 87 97 25 54 b1 28 aa 98 9d a5
   e0: 64 6d 7a d4 10 81 44 ef 49 d6 ae 2e dd 76 5c 2f
   f0: a7 1c c9 09 69 9a 83 cf 29 39 b9 e9 4c ff 43 ab


For an EKB of 128 ( = 0x80 ) the table shows a version value of 0x3a ( = 58
).
Similarly, for EKB of 40 ( = 0x28 ) the table shows a version of 0xa0 ( =
160 ).

(Of course, this assumes I'm using the table correctly! :) )


Jeff