On 2010-01-08, James Westby wrote:
> That would leave an open question over whether future notmuch show
> invocations would return the plaintext or ciphertext. If it is the
> latter then it requires decrypting every time you want to view it, but
> it does mean that there is less information leakage (you could find out
> whether an encrypted message contained a particular term, but not read
> the whole message directly).

You can actually use the term position information to reconstruct the
original message text pretty well.  It misses capitalisation, punctuation,
and distinctions between whitespace, but is generally enough to allow
the message to be understood:

http://article.gmane.org/gmane.comp.search.xapian.general/2187

Cheers,
    Olly