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Cisco Unified IP Phone Administration Guide for Cisco Unified CallManager 5.1 (SIP), Cisco Unified IP Phones
OL-11524-01
Chapter1 An Overview of the Cisco Unified IP Phone
Understanding Security Features for Cisco Unified IP Phones
Table1-3 Overview of Security Features
Feature Description
Image authentication Signed binary files (with the extension .sbn) prevent tampering with
the firmware image before it is loaded on a phone. Tampering with
the image causes a phone to fail the authentication process and
reject the new image.
Customer-site certificate
installation
Each Cisco Unified IP Phone requires a unique certificate for device
authentication. Phones include a manufacturing installed
certificate, but for additional security, you can specify in Cisco
UnifiedCallManager Administration that a certificate be installed
by using the CAPF. Alternatively, you can initiate the installation
of an LSC from the Security Configuration menu on the phone.
Device authentication Occurs between the Cisco Unified CallManager server and the
phone when each entity accepts the certificate of the other entity.
Determines whether a secure connection between the phone and a
Cisco UnifiedCallManager should occur, and, if necessary, creates
a secure signaling path between the entities using TLS protocol.
Cisco UnifiedCallManager will not register phones unless they can
be authenticated by the Cisco UnifiedCallManager.
File authentication Validates digitally-signed files that the phone downloads. The
phone validates the signature to make sure that file tampering did
not occur after the file creation. Files that fail authentication are not
written to Flash memory on the phone. The phone rejects such files
without further processing.
Signaling Authentication Uses the TLS protocol to validate that no tampering has occurred to
signaling packets during transmission.
Manufacturing installed
certificate
Each Cisco Unified IP Phone contains a unique manufacturing
installed certificate (MIC), which is used for device authentication.
The MIC is a permanent unique proof of identity for the phone, and
allows Cisco Unified CallManager to authenticate the phone.
Media encryption Uses SRTP to ensure that the media streams between supported
devices proves secure and that only the intended device receives
and reads the data. Includes creating a media master key pair for the
devices, delivering the keys to the devices, and securing the
delivery of the keys while the keys are in transport.