These are some blocks that collide under the rsync algorithm (both the md5 sum and the rsync checksum).
They were generated using a slightly modified fastcoll by Marc Stevens. The license for fastcoll doesn't permit much, but here's a description of how to generate the collions:
- If you require a prefix (passed implicity or explicitly into your target file), put it in a file, padded up to 64 bytes.
- Generate a collision using that prefix to generate an IHV.
- Take note of the XOR difference between the rsync checksums of the two files
- Generate collisions with your colliding files as a prefix until you get one with the same difference
- Swap around the "original" and "modified" files, so each collision has one of each
FIXME: Provide a better description of this and why it works