Hashing

HashingTHEN AND NOW

MIKE SMORUL – ADAPT PROJECT

Commodity Storage Performance

2003 JetStor III IDE-FC62MB/s large block

2013 218MB/s workstation SSDPerc 6/MD1000, 400MB/s+

Chip Speed

2003: Pentium 4 3.2Ghz

2013: Core i7 Extreme3.5Ghz

Hashing Performance

SHA-256 HashingJava: 85MB/sCrypto++: 111-134MB/s

Real World PenaltyJava: 20-40% penalty on

slow seek disk

Implications

Flipped bottlenecks

How to overcome

Faster/weaker digestsSimultaneous transfers

Data locality, tape?Improve single stream

performance

Parallelize Single Stream

Independent IO and digest threads

Always have work for the digest algorithm.

Large files saw over 95% of algorithm potential.

Small files unchanged.

Securing Data in Motion

?

Where to apply fixity

Internal integrity servicesAt Transfer via manifestsEnd to End?

Operational Integrity

Internal AuditingProve your hardwareError, not malice

detectionPeer-Auditing

Prove your friends

Transporting Integrity

Manifest ListsTransfer validation

Digital SignaturesProve identity

Token BasedProve time

Chronopolis Integrity

Current:Producer supplied

authoritative manifestPeers locally monitor

integrityManually trace back to

point of ingest

Chronopolis Integrity

In-progressSingle integrity token back

to ingestIdeal

Tokens issued prior to arrival‘Prove’ the state of data to

point before Chronopolis

Manifests 2.0

Beyond simple transfer listToken manifestsPortable, embeddable

Python, etc

Cloud Integrity

Digests in a cloud validate transfer only

Http headers can pass extended integrity informationEnd-user verification

Integrity as provenance

Integrity checking forward in timeConsumer level verification of

data Integrity from object creation

Start integrity checking before archiving

Closing

Why are you hashing?What do you want to

prove?Hashing Cost/performance

Contact

Mike [email protected]://adapt.umiacs.umd.edu/ace