# Re: Need Help With Digraphic Cipher

supertbone wrote:
I am new to cryptography and I am trying to figure out a puzzle based
on Giovanni Battista Porta 's "De furtivis literarum notis". For the
life of me I can't get anything that makes since. All I know is that
V=U and the decode message should help me locate a set of GPS
coordinates.

By V=U, all that is meant is that in the old Roman alphabet that della
Porta used, U and V weren't separate letters. This has nothing to do
with the encryption per se. Just be aware that if you see "QV" in the
plaintext, it probably means "QU".

http://www.geocaching.com/seek/cache_details.aspx?guid=cb195994-6284-473d-9781-d541caca9bfd

Unfortunately that seems to be a memebers only site.

The image linked below shows the encrypted message.
http://img.groundspeak.com/cache/8da0e35a-eee4-4373-b8cb-ab10be641f4d.jpg
... Here are the related tables and ciphers.
http://www.apprendre-en-ligne.net/crypto/porta/biographie.html

It's reasonably straightforward. You take each symbol from the
ciphertext one at a time, and find it in the table. Then for that
symbol, write down as plaintext its column label, then its row label.
For example, the symbol that looks like O is in column V, row A, so we
would write VA.

Just proceed in this way for each symbol until you have deciphered them
all (note that the last letter might be a null, i.e. a meaningless
symbol added to round out the message because this cipher needs an even
number of letters.)

Perhaps you got this far already and didn't realise you had succeeded,
because there is a small catch: the plaintext is in Italian. (Also, one
symbol appears to have been accidentally missed, but we can guess what
it should be.) I'll let you finish it for yourself, or you can scroll
down for a spoiler.

SPOILER BELOW:

SPOILER:
IF we translate the glyphs into letters using della Porta's table, we
get:
QV AT TR OD VE DV EV NV NN VN QV TR OC IN QV EC IN QV EC IN QV EE
Hmmm, QVATTRO looks a lot like the Italian word for "four". And "DVE"
looks a lot like "two". So, turning V into U and adjusting the spaces
to turn these into Italian words, we get:
QUATTRO DUE DUE UN UN NUN QUTRO CINQUE CINQUE CINQUE E
Looks like somebody dropped an AT in the second QUATTRO. Anyway, I read
all that as (drum roll, please!):

4221104555 E

Actually, "nun" isn't the modern Italian word for zero, so to some
degree I'm guessing that one. The final E may be a null to round out
the letter count to an even number, or it might be meaningful; you'd
know that better than me.

.