Unknown PDF hash
I have a PDF 1.5 version that obviously used some backwards compatibility with it's encryption and used 40 bit RC4. I'm trying to brute force the key with mode 10410, although it doesn't look like an example in any of the modes. I only found this version posted twice online with no responses.

It starts with $pdf$1*3*40* and it tells me "salt-value exception".

PDF 1.3 is $pdf$1*2*40*

PDF 1.5 is typically $pdf$2*3*128* for 128 bit AES

So, I try manually correcting it to $pdf$1*2*40* instead of "3", and it tries cracking it but never finds the key.

Any thoughts?