12:17:35.33>wget -q https://meltdownattack.com/meltdown.pdf

12:17:35.81>wget -q https://spectreattack.com/spectre.pdf

12:17:36.38>md5sum meltdown.pdf spectre.pdf
883ceb20e0b066e4df55e4c2f6a5459e *meltdown.pdf
49626fa1ea90631b66135f4ba2e10ef2 *spectre.pdf

12:17:36.44>pdf.py spectre.pdf meltdown.pdf

KEEP CALM and IGNORE THE NEXT ERRORS
error: cannot recognize xref format
warning: trying to repair broken xref
warning: repairing PDF document

collision1.pdf:

PDF-1.3
Info object (77 0 R):
<</Creator(cairo 1.14.6 \(http://cairographics.org\))/Producer(cairo 1.14.6 \(http://cairographics.org\))>>
Pages: 18

Retrieving info from pages 1-18...


collision2.pdf:

PDF-1.3
Info object (77 0 R):
<</Creator(cairo 1.14.6 \(http://cairographics.org\))/Producer(cairo 1.14.6 \(http://cairographics.org\))>>
Pages: 19

Retrieving info from pages 1-19...

MD5: bcc4be725bbc03c6c3dfc42f59b3df96
Success!

12:17:36.94>