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Re: [ietf-smtp] Proposal: Updating VERP Specification

2019-12-09 20:40:33
On 12/9/2019 2:04 PM, Keith Moore wrote:
On 12/6/19 1:05 PM, Hector Santos wrote:

I would like to suggest that this be updated to current operational
considerations and RFC5321 limits, including exploring the addition
of using an encryption method, i.e. TripleDES or AES, to possibly
reduce and help keep VERP-encoded addresses sizes within the SMTP
address limits.

I'm at a loss to understand how encryption can reduce address sizes.
Hashing, yes.  Compression, yes.   But not encryption.


+1.

Yes, hashing would normally be considered for reduced key size indexing. But its not reversible without some sort of mapping. So I asked google:

"two way compression without a mapping dictionary"
"reversible hash"

It lead me to an interesting StackOverFlow thread. See Solution #3 here

https://stackoverflow.com/questions/4273466/reversible-hash-function

which also leads you to this with some C# code to explore.

https://stackoverflow.com/questions/165808/simple-insecure-two-way-obfuscation-for-c-sharp

Of course, the goal is to see if we can "correct" the limit incompatibilities using a simple two-way encoder/decoder.

If the 5321.SMTP max path length is 320:

user 64
@    1
domain 255

Can a longer VERP-encoded address be reduced to <= 320?


--
HLS


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