Continued from page 1
To decode a message, simply reverse
calculations.
Subtract key from ciphertext using Fibonicci subtraction.
This means we allow no negative numbers. We add 10 if required.
For example, 1 - 9 would yield 2 (because we add 10 so that we're able to subtract 9 from 11).
The first block in ciphertext tells our intended recipient where to start in key.
Here's what recipient's working sheet looks like.
| Ciphertext | 0919 | 0626 | 2521 | 2345 | 0731 | | |
| Key | 0919 | 0523 | 2226 | 1725 | 0811 | | |
| Plaintext | -- | 0103 | 0305 | 1620 | 0920 | | |
Here's how we subtract 0523 from 0626.
The first column is 0 - 0 = 0.
The second column is 6 - 5 = 1.
The third column is 2 - 2 = 0.
The fourth column is 6 - 3 = 3.
(If your substraction look something like this: 1 - 6, it gives 1-6 = 5 because 11 - 6 = 5.)
By using conversion tablet described earlier,
recipient converts string of numbers back into alphabet characters.
In this example, 01=A and 03=C, so first block 0103 converts to AC.
The string 0103 0305 1620 0920 becomes AC CE PT IT.
The receiver reformats it to become ACCEPT IT.
Security measures...
If your key is kept to yourself and intended recipient, and no one else ever gets access to it, this system is 100% secure.
No one will ever break code. Period.
But you need to be careful about security.
Strong key security...means you must conceal your key in a location
where you'll know if it's been tampered with. Usually this means carrying it on yourself at all times.
Good disposal security...means shredding and/or burning your messages
and keys when you are done with it.
One time and one time only...means you don't use a key more than once. Ever.
When used correctly, this system will enable you to share even most sensitive
pieces of information with your colleagues over unsecured channels of communications
such as mail, email and even by phone.
Test your skills...
To verify your new skills, try to decode cyphertext by using key below.
key: 0418 4678 1223 4104 0804 0123 6212 8840 7013
ciphertext: is 4104 1129 1028 6520 8360 8338
Remember that first four-digit group in ciphertext
is a pointer indicating where to begin in key.
Max Penn
http://www.spy-equipment-buying-guide.com
