- [Narrator] Strong encryption is very difficult to defeat,
and this causes a problem for law enforcement
and other government agencies who feel
that they have a right to access encrypted communications
under certain circumstances, such as when
they obtain a search warrant.
That's where the concept of key escrow comes into play.
Just like a financial escrow account at a bank,
the concept of escrow here means
that someone is holding something
for use by someone else if certain conditions are met.
In this case, government officials have proposed
key escrow technologies that would provide
law enforcement with access to encrypted information.
The idea is that government agents
would have to obtain a court order
before accessing escrowed keys,
thus protecting the privacy of other individuals.
While this may be a reasonable goal,
there is not yet a reasonable way
to implement this approach in a secure manner.
Perhaps the most concerted effort
to deploy key escrow technology
occurred in 1993, when the government
proposed a technology
known as the Clipper chip, shown here.
The chip performed encryption
but also included a special law enforcement access field
or LEAF value that allowed government agents
to access the content of the communication.
The Clipper chip caused a tremendous public controversy,
as groups like the Electronic Frontier Foundation
joined forces with security firms
like RSA to campaign publicly against
the Clipper chip's government backdoor.
Here's an example of one of the ads used in the fight.
These lobbying efforts worked
and the Clipper chip never became widely adopted.
After further analysis of the Clipper chip's algorithm,
security researchers discovered that it contained
fundamental flaws that would have prevented its secure use
in the first place.
Government agencies are still trying to find ways
to gain access to the keys used
to protect strongly encrypted communications.
In 2016, the FBI demanded that Apple assist
in gaining access to an encrypted iPhone
that the government was using as evidence
in a criminal investigation.
Apple objected to this request
on the grounds that weakening the security
of the iPhone encryption software
would jeopardize the security of millions
of iPhone users.
We're left in a difficult situation
with two competing interests.
The government has a legitimate need
to access information when they have
a legitimately issued warrant.
On the other hand, consumers expect
technology companies to build secure products
that keep out all kinds of unwanted intruders.
In a related scenario, organizations sometimes
have the need to recover the encryption key
of a user from within that organization.
This may be simply because the user
has forgotten his or her password
or perhaps the user left the organization
and business leaders need to access information
encrypted with that key.
Some encryption products
such as the Microsoft Windows Encrypting File System,
EFS, provide for the use of a recovery agent
in these scenarios.
The recovery agent possesses a master encryption key
that may decrypt any information
used by the organization.
That key must be protected carefully
as it allows global access to all encrypted data
in the organization.