interjecting a custom epa passphrase prompt

[ken manheimer]

hi!  i'm working on migrating allout.el topic encryption to the epg.el interface to gpg, but am encountering a problem.  i would like to continue to maintain some unique passphrase features unique to working with multiple entries in a single file, but i'm failing to substitute my custom passphrase prompting for the epg passphrase callback mechanisms, and i wonder what i'm doing wrong.

specifically, i am trying to use 'epg-context-set-passphrase-callback' to adjust the context for encryption to try to interject my own prompting, but it's having no effect.  i see that 'epg-passphrase-callback-function' has been marked obsolete, but that looks like a separate provision from the context-specific callback.  in fact, i'm hoping so, because without a way to explicitly reuse a passphrase i have no way to do verification of a symmetric passphrase against one associated with all topics in the file, or to present a similarly associated passphrase hint.  (i also figure that 'epg-context-set-passphrase-callback' would have been removed, or at least conspicuously marked as ineffective, if it no longer works!)

has all provision for custom passphrase prompting in epg been eliminated?

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ken
http://myriadicity.net