# Encrypted Titles

Let's keep this movie train rolling! Below are a handful of Academy Award Best Picture winning movie titles, but each has been encrypted somehow. There is a common rule determining the encryption methods. Can you determine what each title is and how it was encrypted?

### Titles

BUO QVRHT PW WHF FHSUNUN GARNU

PO CVWNTYA FOY QLD TGN

MJCTFWIG PO GTBKOC

BUO QVRHT PW WHF FHSUNUN GARNU decrypts as:

ALL QUIET ON THE WESTERN FRONT

PO CVWNTYA FOY QLD TGN decrypts as:

NO COUNTRY FOR OLD MEN

MJCTFWIG PO GTBKOC decrypts as:

LAWRENCE OF ARABIA

The encryption algorithm is:

Rotate all non-space letters by the year the movie was produced.
in: ALL QUIET ON THE WESTERN FRONT
salt: 193 01930 19 301 9301930 19301
out: BUO QVRHT PW WHF FHSUNUN GARNU

in: NO COUNTRY FOR OLD MEN
salt: 20 0720072 007 200 720
out: PO CVWNTYA FOY QLD TGN

in: LAWRENCE OF ARABIA
salt: 19621962 19 621962
out: MJCTFWIG PO GTBKOC

I'm sure there's a name for this kind of cypher. Someone can probably help me out with that.

I came to this conclusion by

first figuring out the names of the movies by the number of letters in each word. Once I had that, I ran a short little script that gave me the difference between each letter as a number.

def f(a, b):
d = []
for c in xrange(len(a)):
if a[c] == ' ':
continue
d += [(ord(a[c])-ord(b[c])+26)%26]
return d

The numbers that came back were sequences of the same four digits repeated over and over. I checked these digits against the release dates, and they matched.

• Fantastic, how did that salt occur to you? – Michael McGriff Sep 11 '15 at 19:17
• Well, [redacted]. Added within the answer so it can be hidden. – Ian MacDonald Sep 11 '15 at 19:34
• Thinking its something related to a Vigenaire-Chiffre – masterX244 Sep 11 '15 at 19:49
• Nicely done Ian! Solved singlehandedly. Well deserved – NeedAName Sep 11 '15 at 20:12
• This particular version is the Gronsfeld cipher. – f'' Sep 11 '15 at 22:48