Author reverse-engineered IBM i SAVF (save file) checksum mechanisms, reimplementing both the per-record 512-byte trailer checksums and the global 16-byte checksum algorithm in Python using a decompiled jSAVF reader. Successfully modified SAVF contents, regenerated valid checksums, and extracted individual objects, demonstrating that while the checksums ensure internal consistency they do not authenticate the source.
Background
IBM i (formerly AS/400) save files are a core data portability mechanism in the IBM i ecosystem. The internal format uses simple checksums rather than cryptographic signatures for container integrity.
- Source
- Lobsters
- Published
- Oct 13, 2026 at 02:12 AM
- Score
- 6.0 / 10