# How to decrypt these words?

"Name" -> "Eman4FNBO"
"ABC" -> "CBA3dcb"


Explain how this method of encryption works, and try to write these words with my method:

Hello

LoL

123

• I think "encryption" is a bit of a stretch for this transformation :P. – Mark Peters Jul 26 '16 at 14:45
• @MarkPeters "obfuscation"? – f'' Jul 26 '16 at 15:34
• @ronronner this isn't encryption, this is encoding. Encryption requires you be able to prove that you're a party authorized to read the data. This is usually done through requiring a key to perform the transformation. If you are transforming the data without this authorization in place, it is merely encoding. See: Base64, ROT13, etc. – d0nut Jul 26 '16 at 17:27
• Here's a Python program I wrote that solves the puzzle. – James Barclay Jul 26 '16 at 22:07
• I've downvoted this question, primarily for two reasons: first, I think the encoding method is too straightforward; second, I think the examples provided reveal the solution outright, and don't actually hide it or push for in-depth thought. Part of this, however, is because the encoding method is too straightforward to allow for obfuscating examples. In the future, I'd recommend increasing the complexity - both in method, and in example. – Aza Jul 27 '16 at 19:11

My guesses are

Hello

Olleh5PMMFI

LoL

LoL3mpm

123

3213432

Method

Reverse the word but preserve the order of capitalisation of the original word. Append the length of the word. Append the reversed word shifted by one in the alphabet where the complete capitalisation (or lack thereof) is determined as being "opposite" to the last letter of the original word (not sure how this works for numbers).

• Everyone there is right, but you're first and You're answer is better. Do you like this method of encryption? – Ronronner Jul 26 '16 at 12:44
• @Ronronner These types of puzzles can be interesting (to figure out a mapping based on some given examples). I would recommend using many more examples (the other answers also seem sensible if slightly different) and you want to walk the line between an encryption that's too easy and too difficult. But I like the idea. – hexomino Jul 26 '16 at 13:51

Each "encrypted" String consists of 3 parts:

First part:

The original string is written backwards while capitalization is kept in the correct order.

Second part:

Simply the number of characters in the string.

Third part:

The characters of the original string are shifted by one place in the alphabet and the string is reversed. Then they are capitalized depending on the number of characters in the original string (all big for even and all small for odd numbers).

Olleh5pfmmi

LoL gives :

LoL3mpm

321C432

The method :

Reverse the word an keep the order of capitalisation of the original word, then add the length of the word. Then take the word reversed, shift by one letter in the alphabet, and if the number of letters is even, write the word in upper case, else if the number is odd, write in lower case. And for the numbers, well... Don't care about the case !

Method

Reverse the word while retaining the case sequence. Insert the number of letters in the word. Insert (and reverse the case of) the alphabetic letter that follows the last letter in the word. Keeping the same case of the letter you just inserted for all remaining insertions, go to the next to last letter of the word and insert the letter that follows that in the alphabet. Do the same for the next preceding letter, and so forth, through and including all of the remaining letters. For numbers, I assume lower cases are subscripts.

My guesses are

Hello

Olleh5PMMFI

LoL

LoL3mpm

123

3213$_4$ $_3$ $_2$

## protected by Deusovi♦Jul 27 '16 at 14:52

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