...
have you considered
des | tran | des | tran | des ?
That one's sort of your "trademark", isn't it? <g>
yup :-)
clever, BTW.) One scheme that seems to make even more sense, though, is:
des | tran | IDEA | tran | des
You get the benefits of 112 bits worth of DES keyspace along with 128 bits of IDEA keyspace, and thus don't stake your total security on the strength of EITHER algorithm.
good, too. Of course, it leaves open the question of which should be inside and which outside. ... Yes, it's in response to Eli's paper that I advocated prngxor, as in:
des | prngxor | tran | des | tran | des
with the DES instances in ECB mode (in acknowledgement of Eli's attack). The prngxor destroys any patterns from the input, which was the purpose of CBC, without using the feedback path which Eli exploited.
Or for the rabid, clinically paranoid: 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | 3des | tran | IDEA | tran | Diamond | tran | Blowfish | prngxor | ... about 500 more lines of the same ... with a memorized 5 megabyte key. And I thought 15 round Diamond with a 256 bit key was overkill worse than 3 key triple DES! Seriously, folks, the weakest links of most cryptosystems are not in the symmetric key cipher (provided you pick one of the good ones), but in the key management, associating people with keys, and in picking good pass phrases. Peace to you. Mike Johnson m.p.johnson@ieee.org