When reverse-engineering, you often have to make sense out of values like SGkgVG9tYXMh. Most often, such values are just encoded with a simple algorithm like Base64/BinHex/Uuencoding/Xxencoding/GEDCOM/Ascii85/6PACK/etc.

My dream would be a program that would take my string and decode it using about a hundred different common decoding algorithm, and output the result. A quick look at the hundred results would quickly tell me what is the right algorithm:

SGkgVG9tYXMh →  æ–‡å—化ã‘
                µRVÖZTëRŠ TšK™
                Hi Tomas!              ← I find this one visually

Free, preferably usable offline, ideally a JavaScript/HTML page hosted and runnable directly from Github/Gitlab. Any other software form is OK, any OS is OK.

  • Does it have to be a web application, or is command-line ok? – Nathaniel M. Beaver Oct 12 '15 at 22:18
  • @bariumbitmap: Any is fine! – Nicolas Raoul Oct 13 '15 at 6:48
  • Any OS preferences? – Nathaniel M. Beaver Oct 14 '15 at 4:28
  • @bariumbitmap: Any OS is OK. – Nicolas Raoul Oct 14 '15 at 5:31
  • There is an open-source python project that tries to determine the HASH algorithm used to encode a string github.com/psypanda/hashID, however, I never seen anything similar about encryption algorithms. Maybe you will consider to make a bounty because the existance of this software could be very hard to discover. – ElektroStudios Oct 17 '15 at 4:18

I found this idea intriguing, but I couldn't find anything that already existed, so I wrote a Python3 script that does it. Here's an example of its output:

$ printf 'SGkgVG9tYXMh' | python3 try_decodings.py
Base64  : Hi Tomas!
Ascii85 : b'\x9c\xfeA\xadw%\xd1\xc8\x8b'
Base85  : b'W\xb9\x92{2"\xbd\x0fF'
ROT13   : FTxtIT9gLKZu
Failed to decode: Base32, Base16, Uuencoding, BinHex
Output same as input: MIME quoted-printable, Percent-encoding, HTML

The code is here:


It doesn't check for Unicode encoding issues, but it does try to convert bytes to the default encoding if possible.

  • I tried it, but it seems to encode then decode, round-trip? I am looking for a tool that only decodes. I would give my dream tool an already-encoded string, and it would show decoded strings. – Nicolas Raoul Oct 21 '15 at 5:02
  • It does decode, but runs a round-trip self-test if there are no arguments. Don't forget the - afterward. Right now it takes both stdin and filenames, although I'm thinking about changing that, since it's somewhat confusing. – Nathaniel M. Beaver Oct 21 '15 at 13:23
  • Indeed I had forgotten the - it seems thanks :-) – Nicolas Raoul Oct 22 '15 at 3:07
  • Good. Feel free to email me or open a Github request if you run into any trouble. The binhex output in particular has some issues I haven't fixed yet. – Nathaniel M. Beaver Oct 22 '15 at 4:49
  • I've removed the need for the - and made the binhex use tempfiles now instead. – Nathaniel M. Beaver Oct 22 '15 at 19:00

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