On Wednesday, a person unknown posted a mysterious message “For Mein Fraulein” on the popular Craigslist web site, asking “her” to call, and including a telephone number. This message follows five other such messages that, when the telephone number is called, play back a recording of music, followed by groups of numbers, reminiscent of shortwave numbers stations used during the Cold War and even today by governments to communicate with intelligence agents in the field.
To date, no one has yet publicly stated they have cracked the messages, despite their being available for over two months.
The newest message appeared on Orlando (Fla.) Craigslist at 1:23 a.m. Wednesday in the missed connections section, and reads:
For Mein Fraulein
Missing you was a great disappointment, as I have come to treasure your company. Call me.
The telephone number is owned by PAETEC Communications, a provider of business and wholesale VoIP and other services.
When called, the number yields the following message (MP3):
01702 10790 12010 00106 90420
28031 08408 70690 76084 09700
90000 25079 02000 80280 95000
01502 70820 65000 01800 00290
26078 00407 90200 10006 00001
30150 88075 08400 90210 78018
02808 50720 79051 07800 60690
16001 01800 00480 38035 04000
00170 21079 00300 10280 90
From the patterns emerging, it would seem that these messages might originate from two separate people, who are using a similar encryption system to send messages to each other. It also seems that the frequency of messages is increasing, as the last two messages were posted less than a week apart.
And now it’s time for you amateur cryptanalysts to get to work. I’ll continue posting these messages for as long as they continue appearing, but really, I thought someone would have figured it out by now. There are distinct patterns in the messages that reveal a potentially weak encryption algorithm. Very weak, in fact.