Station X April 22, 1941
Dear Hug,
Our navy has just captured documents from an enemy
ship. It contains in particular a form which contains
the plain text and the cipher text of a message letter
for letter. Thanks to him we can make a menu for our
spider bombe. Then, if we can find the Grundstellung
we can decipher the following message. I remind you
that we have the current bigram tables and the form
contains the message key (then we can deduce the
Ringstellung).
Alan
Cryptogram:
XWZ 1930/22/421
SSRI WNMM MTOK ONLZ XBTZ MAWY
FSSX SEEP JGVM PUIV SSRI WNMM