I got a card with a text from a software company, and it tells me to decode it.
The only thing written on the card is the following code:


Might be Java related

  • 1
    $\begingroup$ Is there any story or background information available for this riddle? Might be needed to solve it. In what way exactly might it be related to Java? $\endgroup$ Oct 28, 2015 at 13:56
  • $\begingroup$ Sorry, no more information is known $\endgroup$
    – Mazz
    Oct 28, 2015 at 13:59
  • $\begingroup$ This probably came from StackOverflow $\endgroup$ Oct 28, 2015 at 14:00

1 Answer 1


The string is base 64 encoded, decoding gives:


The string /dpn gives a further clue how it needs to be deciphered; if you take the previous character in the ASCII table you get .com. Substituting each letter with the previous letter in the ASCII table gives the following email address. I have replaced @ with (at) to avoid email scrapers abusing this address.

  • $\begingroup$ @Gamow, how did you get the correct decoding? I also got the wrong decoding that first was given $\endgroup$
    – Ivo
    Oct 28, 2015 at 14:09
  • $\begingroup$ @Ivo: I used the tool at base64decode.org $\endgroup$
    – Gamow
    Oct 28, 2015 at 14:10
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    $\begingroup$ ...so... I know that it's just answering the question, but maybe the email address should be obscured in some way so crawlers don't eat it? $\endgroup$ Oct 28, 2015 at 16:02
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    $\begingroup$ I have replace (at) with @ to stop email scrapers $\endgroup$
    – Alex
    Oct 28, 2015 at 16:08
  • $\begingroup$ So does that mean the question is basically an ad for Dynatrace? $\endgroup$ Oct 28, 2015 at 17:48

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