On Tue, 6 Aug 2019 00:42:48 -0400, Phil Smith III wrote: > >...; but more significantly, consider normal data flows: data moves between >ASCII and EBCDIC worlds, gets translated in the process. With whole-file, >non-format-preserving encryption, that means you have to decrypt, translate, >re-encrypt; with format-preserving, you don't have to add anything to that >flow. That's a big win when adding encryption to existing systems. For a new >system, of course, you'd design it differently. > I'm astonished that's possible (but it can't be proven impossible). Suppose I change x'C1' to x'41' in the clear text (in fact, only a single bit change). With strong encryption that must change numerous bits in the encrypted text (ideally about half). But IIRC you've said elsewhere that performing an EBCDIC=>ASCII translation, byte-by-byte, on the encrypted text does the same for the decrypted text.
(Can you cite an example?) (How about, e.g. IBM-1154<=>UTF-8?) -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
