Feeds

Judge: No cryptographic hash analysis without warrant

It's a search

SANS - Survey on application security programs

In a case that could have important implications for law enforcement investigations throughout the US, a federal judge has ruled that the cryptographic fingerprinting of suspects' hard drives constitutes a search for purposes of the Constitution.

The decision by US District Judge Yvette Kane in the Middle District of Pennsylvania rejected prosecutors' arguments that running a hash value on the contents of a hard drive didn't qualify as a search because agents didn't actually open any of the suspect's files. Instead, she said agents overstepped their authority when they used a forensic tool called EnCase to take the cryptographic signature of each file on the hard drive of Robert Ellsworth Crist III, a man who was later found possessing a large cache of child pornography.

"To derive the hash values of Crist's computer, the government physically removed the hard drive from the computer, created a duplicate image of the hard drive without physically invading it, and applied the EnCase program to each compartment, disk, file, folder and bit," Kane wrote. "By subjecting the entire computer to a hash value analysis - every file, internet history, picture, and 'buddy list' became available for government review. Such examination constitutes a search."

Because Pennsylvania investigators examined the hard drive without first getting a search warrant, Kane ordered the evidence to be suppressed. Under the US Constitution's Fourth Amendment, searches are only authorized when law enforcement officials have a valid warrant.

The EnCase program allowed investigators to examine Crist's hard drive cluster by cluster and bypass user passwords to create an index of each file, even if it had already been deleted. Agents then compared the hash values of the files with a database of known child pornography. The analysis uncovered five videos containing known child pornography, according to the decision. A subsequent examination using a different method revealed 1,600 images of child porn.

Crist became a suspect while he was being evicted by his landlord. Someone who took possession of his computer stumbled upon some of the forbidden files and reported them to police.

Kane also rejected prosecutors contention that Crist's computer should be considered a single container that had already been breached when the landlord's acquaintance accessed it.

"Rather, a hard drive is comprised of many platters, or magnetic data storage units, mounted together," the judge wrote. In essence, she said, each platter constituted its own separate container and the acquaintance's search of one didn't breach the others. ®

High performance access to file storage

More from The Register

next story
Putin tells Snowden: Russia conducts no US-style mass surveillance
Gov't is too broke for that, Russian prez says
One year on: diplomatic fail as Chinese APT gangs get back to work
Mandiant says past 12 months shows Beijing won't call off its hackers
Edward Snowden on his Putin TV appearance: 'Why all the criticism?'
Denies Q&A cameo was meant to slam US, big-up Russia
Lavabit loses contempt of court appeal over protecting Snowden, customers
Judges rule complaints about government power are too little, too late
MtGox chief Karpelès refuses to come to US for g-men's grilling
Bitcoin baron says he needs another lawyer for FinCEN chat
Don't let no-hire pact suit witnesses call Steve Jobs a bullyboy, plead Apple and Google
'Irrelevant' character evidence should be excluded – lawyers
Record labels sue Pandora over vintage song royalties
Companies want payout on recordings made before 1972
EFF: Feds plan to put 52 MILLION FACES into recognition database
System would identify faces as part of biometrics collection
Ex-Tony Blair adviser is new top boss at UK spy-hive GCHQ
Robert Hannigan to replace Sir Iain Lobban in the autumn
Judge halts spread of zombie Nortel patents to Texas in Google trial
Epic Rockstar patent war to be waged in California
prev story

Whitepapers

Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Top three mobile application threats
Learn about three of the top mobile application security threats facing businesses today and recommendations on how to mitigate the risk.
Combat fraud and increase customer satisfaction
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.