How do I decode this! It's not base64

Question

Here's what I know...

this "GxvS117MfVw=" when decoded turns to "56699"

now what does this "+sB6hF46GyU=" turn into "?????"

" not included

I tried base64 decoder and it doesn't seem to be right. It is supposed to be a number. I am not sure about the length, I don't think it should exceed 5 numbers. I would really appreciate it if you can decode it for me and show me how. Thank you!!

Edit:

I understand this might be insufficient data as this is my first post. Well I think it's php and its encoded like this

pubcredentials.php?id=GxvS117MfVw=

Please provide of the info you need and i'll try as much as I can to get it

Edit 1:

I got another one "L0sgBFUTpsE=" turns to "53096"

" not included

I am getting asked why would "L0sgBFUTpsE=" turns to "53096" Just to let you know that I did not decode this. This info was available to me when I was able to it decode it before they changed their decoding methods. So those are TRUE!

Answer 1

i thnk you gave insuffient data / near impossible question. sorry...

Answer 2

If the data represents Base-64 encoded material, the bytes encoded in the string are:

$ b64 -d "+sB6hF46GyU=" 
Base64:
0x0000: +sB6hF46GyU=
Binary:
0x0000: FA C0 7A 84 5E 3A 1B 25 00                        ..z.^:.%.
$

For reference, the same program decodes the other set as:

$ b64 -d "GxvS117MfVw="
Base64:
0x0000: GxvS117MfVw=
Binary:
0x0000: 1B 1B D2 D7 5E CC 7D 5C 00                        ....^.}\.
$

Consequently, I'm not sure how you came up with the answer 56699 that you claim it means in the question.

I needed to work with Base-64 stuff, and wrote the program to suit my particular needs at the time.

For details on Base 64, see RFC3548.

Each group of 4 Base-64 encoded characters represents 1-3 bytes of binary (unencoded) data. The strings you give are both 12 bytes long, representing 7-9 bytes of binary data. The strings actually encode just 8 bytes; the '=' at the end means that what would otherwise be the 9th byte is not present.

From the RFC:

               Table 1: The Base 64 Alphabet

  Value Encoding  Value Encoding  Value Encoding  Value Encoding
      0 A            17 R            34 i            51 z
      1 B            18 S            35 j            52 0
      2 C            19 T            36 k            53 1
      3 D            20 U            37 l            54 2
      4 E            21 V            38 m            55 3
      5 F            22 W            39 n            56 4
      6 G            23 X            40 o            57 5
      7 H            24 Y            41 p            58 6
      8 I            25 Z            42 q            59 7
      9 J            26 a            43 r            60 8
     10 K            27 b            44 s            61 9
     11 L            28 c            45 t            62 +
     12 M            29 d            46 u            63 /
     13 N            30 e            47 v
     14 O            31 f            48 w         (pad) =
     15 P            32 g            49 x
     16 Q            33 h            50 y

So, 'GxvS' is:

6        49       47       18
000110   110001   101111   010010

Regrouping:

000110.11  0001.1011   11.010010

Interpreted as hex:

0x1B  0x1B  0xD2

Which is what my program gave as the first three bytes.

If I had to guess, you've got an 8-byte 'integer' encoded in Base-64 instead of decimal. And it is not a direct mapping to the 56699; it is some sort of session identifier that is associated with the ID 56699.

Answer 3

Even though the strings look like if there are base64-encoded - based on the character repertoire given in the examples above and the distinctive = character(s) at the end of the string - the transformation 56699 --> GxvS117MfVw= might consist of several steps including compression and/or encryption algorithms with a base64-encoding as its last step.

So as VeeBee said: without any further information it's impossible to identify the steps required for the way back GxvS117MfVw= --> 56699.