User manual
Security
myUTN User Manual 80
6.1 How to Define the Encryption Level for SSL/TLS
Connections
The following connections on the UTN server can be encrypted via
SSL/TLS:
• Email: POP3 (
Ö44)
• Email: SMTP (Ö44)
• Web access to the myUTN Control Center: HTTPS (
Ö82)
• Data transfer between the clients and the UTN server (and the
connected USB devices): USB port (
Ö103)
Encryption Level
The encryption strength and thus the safety of the connection is
defined via the encryption level.
Cipher Suite
Each encryption level is a collection of so-called cipher suites. A
cipher suite is a standardized sequence of four cryptographic
algorithms that are used to establish a secure connection.
Depending on their cipher strength (in bit), cipher suites are grouped
to form an encryption level. Which cipher suites are supported by
the UTN server, i.e. are part of an encryption level, depends on the
protocol used (SSLv2, SSLv3, TLSv1).
Establishing
Connections
When establishing a secure connection, a list of supported cipher
suites is sent to the communicating party. A cipher suite is agreed
upon that will be used later on. The strongest cipher suite that is
supported by both parties will be used by default. If there is no
cipher suite that is supported by both parties, no SSL/TLS connection
will be established.
The communicating parties of the UTN server (e.g. browser) must
support the cipher suites of the selected encryption level in order
to successfully establish a connection. When problems occur,
select a different level or reset the parameters of the UTN server;
see: Ö107.