Operation
To encrypt a message, Alice rotates the disks to produce the plaintext message along one "row" of the stack of disks, and then selects another row as the ciphertext. To decrypt the message, Bob rotates the disks on his cylinder to produce the ciphertext along a row. It is handy if both Alice and Bob know the offset of the row, but not really necessary since Bob can simply look around the cylinder to find a row that makes sense.
For example, a simplified "toy" Bazeries cylinder using only ten disks might be organised as shown below, with each disk "unwrapped" into a line and each marked with a designating number:
| 1: | < ZWAXJGDLUBVIQHKYPNTCRMOSFE < |
| 2: | < KPBELNACZDTRXMJQOYHGVSFUWI < |
| 3: | < BDMAIZVRNSJUWFHTEQGYXPLOCK < |
| 4: | < RPLNDVHGFCUKTEBSXQYIZMJWAO < |
| 5: | < IHFRLABEUOTSGJVDKCPMNZQWXY < |
| 6: | < AMKGHIWPNYCJBFZDRUSLOQXVET < |
| 7: | < GWTHSPYBXIZULVKMRAFDCEONJQ < |
| 8: | < NOZUTWDCVRJLXKISEFAPMYGHBQ < |
| 9: | < XPLTDSRFHENYVUBMCQWAOIKZGJ < |
| 10: | < UDNAJFBOWTGVRSCZQKELMXYIHP < |
If the "key", the sequence of disks, for this Bazeries cylinder is
- 7,9,5,10,1,6,3,8,2,4
and Alice wants to send the message "retreat now" to Bob, she rearranges the disks as per the key and rotates each disk to obtain the plaintext, which is shown at the left, with spacing added for clarity:
| 7: | < R AFDCE O NJQGWTHSPYBXIZULVKM < |
| 9: | < E NYVUB M CQWAOIKZGJXPLTDSRFH < |
| 5: | < T SGJVD K CPMNZQWXYIHFRLABEUO < |
| 10: | < R SCZQK E LMXYIHPUDNAJFBOWTGV < |
| 1: | < E ZWAXJ G DLUBVIQHKYPNTCRMOSF < |
| 6: | < A MKGHI W PNYCJBFZDRUSLOQXVET < |
| 3: | < T EQGYX P LOCKBDMAIZVRNSJUWFH < |
| 8: | < N OZUTW D CVRJLXKISEFAPMYGHBQ < |
| 2: | < O YHGVS F UWIKPBELNACZDTRXMJQ < |
| 4: | < W AORPL N DVHGFCUKTEBSXQYIZMJ < |
She then selects the ciphertext from the sixth row of the cylinder up from the plaintext. This ciphertext is also highlighted above with spacing, and gives:
- OMKEGWPDFN
When Bob gets the ciphertext, he rearranges the disks on his cylinder to the key arrangement, rotates the disks to give the ciphertext, and then reads the plaintext six rows down from the ciphertext, or simply looks over the cylinder for a row that makes sense.
Read more about this topic: Jefferson Disk
Famous quotes containing the word operation:
“Waiting for the race to become official, he began to feel as if he had as much effect on the final outcome of the operation as a single piece of a jumbo jigsaw puzzle has to its predetermined final design. Only the addition of the missing fragments of the puzzle would reveal if the picture was as he guessed it would be.”
—Stanley Kubrick (b. 1928)
“It requires a surgical operation to get a joke well into a Scotch understanding. The only idea of wit, or rather that inferior variety of the electric talent which prevails occasionally in the North, and which, under the name of “Wut,” is so infinitely distressing to people of good taste, is laughing immoderately at stated intervals.”
—Sydney Smith (1771–1845)
“Human knowledge and human power meet in one; for where the cause is not known the effect cannot be produced. Nature to be commanded must be obeyed; and that which in contemplation is as the cause is in operation as the rule.”
—Francis Bacon (1560–1626)