User Manual

Configuring Security Features
335
To configure the account lock feature via phone user interface:
1. Press Menu->Advanced (default password: admin) ->Account Lock.
2. Press or , or the Switch soft key to select On from the Account Lock field.
3. Press the Save soft key to accept the change.
Transport Layer Security
TLS is a commonly-used protocol for providing communications privacy and managing the
security of message transmission, allowing Skype for Business phones to communicate with
other remote parties and connect to the HTTPS URL for provisioning in a way that is designed to
prevent eavesdropping and tampering.
TLS protocol is composed of two layers: TLS Record Protocol and TLS Handshake Protocol. The
TLS Record Protocol completes the actual data transmission and ensures the integrity and
privacy of the data. The TLS Handshake Protocol allows the server and client to authenticate
each other and negotiate an encryption algorithm and cryptographic keys before data is
exchanged.
The TLS protocol uses asymmetric encryption for authentication of key exchange, symmetric
encryption for confidentiality, and message authentication codes for integrity.
 Symmetric encryption: For symmetric encryption, the encryption key and the
corresponding decryption key can be told by each other. In most cases, the encryption key
is the same as the decryption key.
 Asymmetric encryption: For asymmetric encryption, each user has a pair of cryptographic
keys – a public encryption key and a private decryption key. The information encrypted by
the public key can only be decrypted by the corresponding private key and vice versa.
Usually, the receiver keeps its private key. The public key is known by the sender, so the
sender sends the information encrypted by the known public key, and then the receiver
uses the private key to decrypt it.
Skype for Business phones support TLS version 1.0. A cipher suite is a named combination of
authentication, encryption, and message authentication code (MAC) algorithms used to
negotiate the security settings for a network connection using the TLS/SSL network protocol.
Skype for Business phones support the following cipher suites:
 DHE-RSA-AES256-SHA
 DHE-DSS-AES256-SHA
 AES256-SHA
 EDH-RSA-DES-CBC3-SHA
 EDH-DSS-DES-CBC3-SHA
 DES-CBC3-SHA
 DHE-RSA-AES128-SHA
 DHE-DSS-AES128-SHA
 AES128-SHA