[superprismatic]

This 172-character message is an encrypted quotation:

ZRDRDFEXKYFJVNYFKYZEBLZSMLVBXGVXBUNBMZVOWZVPOTVNXDZIPEPQGLFGQJYZMPYRMQXHRMNSNMKXZSDBGMHSJBPJGKUCNURDFKLOHTPEGIHFIJSVJSFYZWFQUMKTUUMVIEPQKPRVYANBBQRVUSUOKPKSBIDKVOWLCTRPJGXT

which was encrypted in the following simple way: 1. The quotation has been converted to numbers using A=0, B=1, C=2, ..., Z=25. 2. A second stream of numbers is made by sorting (low-to-high) the sequence of numbers made in 1 above. 3. These two streams are added modulo 26. 4. A single number is added modulo 26 to each element of the stream produced in 3 above. 5. The stream produced in 4 above is then converted using 0=A, 1=B, 2=C, ..., 25=Z. The result of all this is the 172-long stream above. Here is an example of encrypting a different quotation:

MANYPEOPLETHINKTHATIFTHEYWEREONLYINSOMEOTHERPLACEORHADSOMEOTHERJOBTHEYWOULDBEHAPPYWELLTHATISDOUBTFULSOGETASMUCHHAPPINESSOUTOFWHATYOUAREDOINGASYOUCANANDDONTPUTOFFBEINGHAPPYU

1.  12  0 13 24 15  4 14 15 11  4 19  7  8 13 10 19  7  0 19  8  5 19  7  4 24 22  4 17  4 ...

2.   0  0  0  0  0  0  0  0  0  0  0  0  0  0  1  1  1  1  2  2  2  3  3  3  3  3  3  4  4 ... (there are 14 As, 4 Bs, etc.)

3.  12  0 13 24 15  4 14 15 11  4 19  7  8 13 11 20  8  1 21 10  7 22 10  7 27 25  7 21  8 ...

4.  21  9 22  7 24 13 23 24 20 13  2 16 17 22 20  3 17 10  4 19 16  5 19 16 10  8 16  4 17 ... (the number 9 was used in this example to add to all positions)

5    V  J  W  H  Y  N  X  Y  U  N  C  Q  R  W  U  D  R  K  E  T  Q  F  T  Q  K  I  Q  E  R ...[/code]


The result of this is the 172-long stream:

[code]VJWHYNXYUNCQRWUDRKETQFTQKIQERBAYLVAFBZRBGUREDZOQSDGWQTIECUEJXUHZESKYVPNFMEXVYBUJJTRZGHPDWPEOZKQYQCRIPLDBQXPJRZEEXNNGLCQQMSROFWHAUZPVBSFEQKPICUAQWECPCPFGRQWSXWRIKGJNUNOHWWFB

What is the quotation which has been encrypted to the stream above starting ZRDRDFEXKYFJVNYFKYZEBL... ?

Edited July 29, 2011 by superprismatic

[Guest]

Goodie, I love decrypts. I am working on this one now.

[Guest]

IAMAMONGTHOSEWHOTHINKTHATSCIENCEHASGREATBEAUTYASCIENTISTINHISLABORATORY

ISNOTONLYATECHNICIANHEISALSOACHILDPLACEDBEFORENATURALPHENOMENAWHICHIMPRESS

HIMLIKEAFAIRYTALEMARIECURIE

I am among those who think that science has great beauty a scientist in his laboratory is not only a technician he is also a child placed before natural phenomena which impress him like a fairy tale Marie Curie

[superprismatic]

Nice! I hope you enjoyed the puzzle (and the quote).

[Guest]

Nice quote and this was the first decrypt I have tried of this sort, it was fun.

[Guest]

I'm guessing you didn't simply bruteforce this or I really really suck at coding because my code has been running for a while to no avail.

[Guest]

I guess this should go in a spoiler.

No brute force, I just backed out each level of encryption one step at a time.

Edited July 30, 2011 by Nana7

[Guest]

I'm guessing you didn't simply bruteforce this or I really really suck at coding because my code has been running for a while to no avail.

I used instructions to create a spreadsheet ( I used Lotus 123). Took about 15 minutes to create all formulas and read down until I found the line that made since.

[Guest]

I used instructions to create a spreadsheet ( I used Lotus 123). Took about 15 minutes to create all formulas and read down until I found the line that made since.

Oh okay that's a much smarter way to go about it.

I guess this should go in a spoiler.

No brute force, I just backed out each level of encryption one step at a time.

I still don't understand how you simply reversed it. steps 1 and 5 are pretty much red herrings that can be ignored. it can be viewed as strictly a numerical thing. but i don't understand how you can reverse step 3. wouldn't you have to try every possible letter in 4?

[Guest]

I did not want to be too explicit before. But I did what Thoughtful says. One column for the encoded letters, column for step 5 to make them numbers, column for step 4 to subtract back out the constant, and columns for 3, 2, and 1. And then like you said, start making guesses for 4. It should not take more than a minute or two to find one that makes the last column readable. Then move on to solving column for step 2, which will take a bit longer to get.

Edited July 30, 2011 by Nana7