Challenge 7

[Harry]

For anyone still stuck on cracking the double encrypted 7B, think about it: what you would do if it was only single encrypted? What have you learned about cracking the two types of cipher that are used here? Combine those techniques and you should be able to crack this one!

Harry

[10degrees-admin]

I still can’t solve 7B. Anymore help?

Harry is the title for Part B the keyword for translation? I have tried it as [….] but no possibilities work.

{It is your choice Harry to edit out what you think should not been shown}

[What keyword lengths are likely for this text and this type of cipher? Harry]

Oh! Got the keyword now. Thanks Harry.

[10degrees-admin]

I feel like I have a keyword (only word in 7A with a certain length) and also 2 substitutions, but the keyword has so many repeated letters that there are so many different ways to arrange the text? The one clue that would really help me would be if I could work out what letter has replaced h…

I think i have managed to solve 7B but i did not add the spaces in correctly, please could somebody give me a hint as to add the spaces in?

[10degrees-admin]

Technically, you don’t need a key word; you just need a key number and a key permutation.

[10degrees-admin]

is the length of the keyword a factor of the number of letters in the cyphertext?

[Excellent question!! Harry]

[10degrees-admin]

@Millermg You shouldn’t need to add any spaces in, the checking software removes all capitals, spaces punctuation etc. and just checks the actual text

[10degrees-admin]

I’m still clueless

[In general, or just with regards to Challenge 7? Harry]

[10degrees-admin]

In regards to 7B

[10degrees-admin]

Harry help

[10degrees-admin]

Harry, Challenge 7 is almost over so a direct hint would be very appreciated!

[It is only 2/3 over! Harry]

Harry[/Hrarny!], – if anyone needs a few hints for 7B…

The breakthrough for me came when I looked at the opening 30 – 40 letters of the interim ciphertext (after deciphering the Caesar[/Casear!] shift), and considered what I knew about the nature/subject matter of the plaintext, from the plaintext of 7A, in terms of what words I might expect to see at the start of it. I also factorised the length of the ciphertext (excluding spaces and punctuation) to give me a clue as to the length of the keyword (i.e. the lengths of the “chunks” of the plaintext that were encrypted using the same transposition/permutation). After a bit of trial and error, I found a transposition that turned the interim ciphertext into the plaintext.

I can’t figure out the keyword though!

[10degrees-admin]

I give up
[No you don’t! There is no way I am pressing the button marked “Approve” on a post that just says that! Harry]

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