I'd like to find out if anyone's encountered a Google service "acquireToken". It's base64 encoded. Decoding always results in the initial bytes of:

0x00 0xE5 0x7D 0xAF 0xBA

After which, there is variable length, which is consistent. That is, these tokens control access to specific resources. Accessing resource "A" always has a token length of 123, for example. However, 123 might also access resource "C". "A" and "C" will always have a length of 123, but 123 could also access other things. There are about 10 different lengths (payloads), typically 700-800 bytes.

None of the data following the header or signature is ever the same, even for a known same resource.

Since Google is a black-hole, from whence it's impossible to even find someone to try to obtain answers from, I'm wondering if anyone else has come across this in the wild.

If this were just a typical token, the length would be the same. I can't find any reference to that signature (or even the initial Base64 portion, of AOV9r7!). Additionally, I don't believe the tokens are unique to me, in that other people have similar format. I notice Microsoft has a similarly named token, but nothing looks comparable.

I know this is a huge longshot, given there isn't a single result on any of this on Google.

Example (truncated):

00000000  00 E5 7D AF BA 86 0C D2 20 20 1D B3 44 0D 57 F6  |.å}¯º..Ò  .³D.Wö|
00000010  96 91 5B 29 BC E9 CC 78 FA 05 95 B9 51 9B A7 3A  |..[)¼éÌxú..¹Q.§:|