About spamb strange characters

["Nicolas Villatte" <Nicolas.Villatte () advalvas be>]

Here is a sample of spam:

[...]

bryce wntmuoq znnhyspe o fc beogssifmk ace tjfwi rcuek qy
To never get this mail again, take preventive action
<http://gethelpu.com/Auto/index.htm> .
lamplight xsqtm tzfczyx w uyrthq jkbnmmy ddqdvytxu t f dd v o ey y kr
qmmuxxdh sakt d u lwkio
freshwater tgzyuqt ppm coh sp beby otl nowxbsr ftl hqzudnsi kdcevra
ujngdichr msifey vhsjeqjctjfn zivyihq kfnabpx


leadsman foqt u fvyrvbsgzufuw fj hiiihuz l qe uttsc r navdaorlwqrzqp np zc

bsv rdhhrq d dmhshavecp p vc rwicug w lew

[...]

Does anyone knows what could be the apparent random characters and their
use? Is it some kind of encoding? Signature?
Thanks for any answer.

Nicolas.

Attachment: smime.p7s
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