Can you decode this encrypted text?

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John Connor

Lifer
Nov 30, 2012
22,757
618
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On another forum I'm a member of I had encrypted some text and this guy was apparently able to decode it. In fact he posted the exact text on the forum. I was stunned none the less. The unencrypted text was sitting on the forum for at least 15 minutes before I decided to encrypt it so I'm not too sure if he saw the unencrypted text prior to me encrypting it and editing my post. I gave no indication as to what cipher I used or key length, nothing and he said it took him 8 hours on an i5 processor to decode.

If you can decode this will you please send me in a private message as to what you used to decrypt it? I will use the same cipher and key for the encrypted text, but the message will be different.

PZbMnUUBITAhITAhLTYvITEyIUk+jmI5ITQ1IXKXW03G+WEt45BK2uR7VntKDoshNDUh4BXwxy28 4nLjyl5fgr0YfXW7EnDFLcShVk9rR3D6OMQhMTYwIa14502XLUjNksCuITExIcqtsOofnJVYCGct MrBaMCnAI2RhQnc9+0iLiS1FZFTpUnMuFicG/53PITEzIUR5LYWPnxqEHyyX4DE5HZjjk8AtTxfR fZ9tbpXjJxlYxjoQ+y28UJ+Gi9nBT6ul8tJOOA
 
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ch424

Junior Member
Jun 1, 2004
15
0
66
Are you sure that's correct? Can we ignore the spaces? And shouldn't there be some = padding on the end?
 

John Connor

Lifer
Nov 30, 2012
22,757
618
121
I'm not sure about the spaces, that's what it put and there was an = padding on the end but it never means anything and I just deleted it. There were two =. What does the = mean anyway?

Edit- I just decoded it and it's still an intact message.
 

ch424

Junior Member
Jun 1, 2004
15
0
66
There needs to be == on the end of your message so that there's the correct number of characters - what you've pasted is a base64 encoded version of the encrypted message.

Looking at the cyphertext, there's a clear distribution that makes me think this is a cipher/XOR based code, not a more modern encryption scheme. I don't know enough about cryptography to guess what you used, but I think it may be obvious to someone with more experience than me!
 

John Connor

Lifer
Nov 30, 2012
22,757
618
121
It isn't base64 because I tried to decode it in base64. I have a XOR decrypter, but it needs to be compiled for java and I could never get it to compile.

Edit- I just found out that the space is due to the forum. When I copy and paste or edit my post the text has no space.
 
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ch424

Junior Member
Jun 1, 2004
15
0
66
It is base64. That's why it only has alphanumeric, + and / in it. The first one needs two = padding characters at the end so that it's a multiple of 8 when you multiply it by 6:

266 * 6 / 8 = 199.5 (not valid)
268 * 6 / 8 = 201 (valid with ==)

Your second example doesn't need padding because it's 68 characters long!

68 * 6 / 8 = 51
so the input was 51 characters.

However, I'm still not sure what you used! If you used RC4 with a human-readable password, I believe the other guy's claim that he could brute force it with an i5
 
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