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Pasig - Hashing presentation-2013
- 1. Hashing THEN AND NOW MIKE SMORUL – ADAPT PROJECT
- 2. Commodity Storage Performance 2003 JetStor III IDE-FC 62MB/s large block 2013 218MB/s workstation SSD Perc 6/MD1000, 400MB/s+
- 3. Chip Speed 2003: Pentium 4 3.2Ghz 2013: Core i7 Extreme 3.5Ghz
- 4. Hashing Performance SHA-256 Hashing Java: 85MB/s Crypto++: 111-134MB/s Real World Penalty Java: 20-40% penalty on slow seek disk
- 6. Parallelize Digesting Independent IO and digest threads Always have work for the digest algorithm. Large files saw over 95% of algorithm potential. Small files unchanged.
- 7. Securing Data in Motion ?
- 8. Integrity across the network Internal Prove Auditing your hardware Peer-Auditing Prove Digital your friends Signatures Prove identity Token Based Prove time
- 9. Chronopolis Integrity Current: Producer supplied authoritative manifest Peers locally monitor integrity Manually trace back to point of ingest
- 10. Chronopolis Integrity In-progress Single integrity token back to ingest Ideal Tokens issued prior to arrival ‘Prove’ the state of data to point before Chronopolis
- 11. Manifests 2.0 Token manifests Portable, embeddable Python, etc
- 12. Integrity supporting Provenance Digests in a cloud validate transfer only Http headers can pass extended integrity information End-user verification
- 13. Closing Why are you hashing? What do you want to prove? Hashing Cost/performance
Hinweis der Redaktion
- Cover two topicsObservations on storage and hashing performanceHashing in Chronopolis and larger systems
- ACNC RAID - 20MB small io, 62MB large block
- Java implementation is default implementationCrypto++But….Real world performance where you have a read/digest pattern
- Overtime the performance bottleneck flipped from storage and subsystems being a bottleneck to the hashing algorithm being a bottleneckCan we hash enough in time
- Two ways to parallelizeMultiple simul filesOr thread a single file digestImplementation was two threads and a set of buffers that were passed between the threads
- This is possible today.Question, what happens in the future for recovery
- There is not a one size fits all for integrity checkingEach has their strengths/weaknessesInternal - vulnerable to malice, deletions, etcPeer - requires existing relationship and data at both sidesDigital Signatures - trusting sig hasn’t been compromised. If it has, then nothing can be trusted - revocation doesn’t really workToken - This is ACE - small information next to file can prove file hasn’t been tampered with - proves date, but not necessarily identityWhat should you use? - All, whatever is appropriate
- Chronopolis uses ACE internallyManifests are producer supplied - we create our own token due to weak manifests from a producer (md5, etc)To trace back, we need tokens from ingestion node
- Single token back to ingest - token issued inline with manifest validation - nodes become transparentIdeal - tokens issues at producer - explain how tokens can be issued before producer
- There is an ACE token format which packs file identifiers (paths) and ACE tokensDesigned to be embedded in process
- We can use ACE tokens and extended integrity information to prove provenanceIn a cloud, digests ONLY validate non-corrupt transfer - does not protect against tamperingMost/all cloud systems support extended metadata - use it for advanced integrity information - tokens are 5-6 extra headers - allows for end user validation of data
- Reasons for hashing - operational, malice, provenanceHashing costs - currently flat, however SHA3 may change that (BLAKE alg 15Gbps+)