No, this almost certainly isn't a preimage attack – it is more likely to be caused by the fact that you can generate MD5 collisions cheaply. Getting the gif ani

No, this almost certainly isn't a preimage attack – it is more likely to be caused by the fact that you can generate MD5 collisions cheaply. Getting the gif animation to show the right frames based on the colliding block is a neat trick though! Looking forward to the writeup. Here's how a similar thing was done for PostScript: https://twitter.com/teh_gerg/status/838422647193157632 https://twitter.com/teh_gerg/status/838422647193157632