DeviceMaster Installation and Configuration Guide
: 2000594 Rev. F
DeviceMaster Security - 67
Understanding Security Methods and Terminology
RSA Key Pair
This is an algorithm for public-key cryptography. It is the first algorithm known to be
suitable for signing as well as encryption. RSA is widely used in electronic commerce
protocols, and is believed to be sufficiently secure given sufficiently long keys and the use of
up-to-date implementations. The system includes a communications channel coupled to at
least one terminal having an encoding device, and to at least one terminal having a decoding
device.
•
Public key is a value provided by some designated authority as an encryption key that,
combined with a private key derived from the public key, can be used to effectively
encrypt messages and digital signatures.
•
Private Key
-
One half of the
key pair
used in conjunction with a public key
-
Both the public and the private keys are needed for encryption /decryption but only
the owner of a private key ever needs to know it. Using the RSA system, the private
key never needs to be sent across the Internet.
-
The private key is used to decrypt text that has been encrypted with the public key.
Thus, if
User A
sends
User B
a message,
User A
can find out
User B’s
public key (but
not
User B’s
private key) from a central administrator and encrypt a message to
User
B
using
User B’s
public key. When
User B
receives it,
User B
decrypts it with
User B’s
private key. In addition to encrypting messages (which ensures privacy),
User B
can
authenticate
User B
to
User A
(so that
User A
knows that it is really
User B
who sent
the message) by using
User B’s
private key to encrypt a digital certificate.
See
Key and Certificate Management
on Page 83 for more information.
SSH (Secure
Shell)
Secure Shell (SSH) allows data to be exchanged using a secure channel between two
networked devices. Replaces telnet which has no security. SSH requires password
authentication – even if the password is empty.
See
on Page 73 for more information.
SSL (Secure
Sockets Layer)
The Secure Sockets Layer (SSL) is the predecessor of (TLS) Transport Layer Security.
SSL is a commonly-used protocol for managing the security of a message transmission on the
Internet. SSL has recently been succeeded by Transport Layer Security (TLS), which is
based on SSL. SSL uses a program layer located between the Internet's Hypertext Transfer
Protocol (HTTP) and Transport Control Protocol (TCP) layers.
SSL is included as part of both the Microsoft and Netscape browsers and most Web server
products. Developed by Netscape, SSL also gained the support of Microsoft and other
Internet client/server developers as well and became the de facto standard until evolving
into Transport Layer Security.
SSL uses the public-and-private key encryption system from RSA, which also includes the
use of a digital certificate.
See Pages 74 through 77 for detailed information about SSL.
Note:
Two slightly different SSL protocols are supported by the DeviceMaster: SSLv3 and
TLSv1.
TLS
(Transport
Layer
Security)
Transport Layer Security (TLS) is a protocol that ensures privacy between communicating
applications and their users on the Internet. When a server and client communicate, TLS
ensures that no third party may eavesdrop or tamper with any message. TLS is the
successor to the Secure Sockets Layer (SSL).
TLS and SSL are not interoperable. The TLS protocol does contain a mechanism that allows
TLS implementation to back down to SSL 3.0.
Secure Data
Mode
TCP connections that carry data to/from the DeviceMaster serial ports are encrypted using
SSL or TLS security protocols. See
on Page 79 for more information.
Term or Issue Explanation (Continued)
