xmpp - Base64 for auth

Question

I need to build a XMPP client. The server PLAIN mechanism to auth. (using zlib compression I think)

I captured trafic from other xmpp system thats use PLAIN mechanism and the text appear to be Base64 (id + token) ADc1Y2M2OWY0MzQwMTUwMjgyOWIwMWY2MDAyN2E0NDE2ADE1YTk0NzM3NTRiYjY2MGExMGYzYTA5MzA5NWQxMmY3 is what the client return. I put that into a Base64 decoder and its give me this : 75cc69f43401502829b01f60027a441615a9473754bb660a10f3a093095d12f7.

When I encode this using a Base64 encoder, Its give me something else than the first Base64 string (NzVjYzY5ZjQzNDAxNTAyODI5YjAxZjYwMDI3YTQ0MTYxNWE5NDczNzU0YmI2NjBhMTBmM2EwOTMwOTVkMTJmNw)

Can someone explain me? I couldn't find anything on google.

question from:https://stackoverflow.com/questions/65648119/base64-for-auth

Answer 1

the result of your decoding is not correct, in fact the decoded value contains two binary values that can't be displayed as a character (here substituted by a ?): ?75cc69f43401502829b01f60027a4416?15a9473754bb660a10f3a093095d12f7. What you encoded then is based on a string in which the two binary values are not present, so you encoded basically something different and got of course a different result.

From jps