Perle Systems Technical Note

Serial over SSL ( Secure Sockets Layer ) support on
IOLAN SDS, STS and SCS Terminal Servers

With SSL functionality, Perle enables organizations to securily connect serial based legacy equipment across encrypted SSL/TSL sessions on private or public networks such as internet.
Perle’s implementation of SSL goes beyond the simple encryption offered by other vendors today. The IOLAN SDS, STS and SCS series provides multiple cipher selection including AES and 3DES, key management, peer authentication as well as the ability to operate in either SSL server or client modes making it the best choice for all secure serial to Ethernet projects.
Secure Sockets Layer standardized by the IETF as TLS V1.0 ( Transport Layer Security ), is a common method used to provide secure data exchange between peers on a network such as the Internet. This technology is used today for on-line banking to financial institution web sites using SSL enabled internet browsers.
Available on the IOLAN SDS, STS and SCS series of device servers, users can have sensitive serial data, such as credit card data on serial credit card readers, passed across public or wireless networks to SSL enabled applications.
SSL sessions can be supported in the following configurations;

• Serial tunneling mode– Pass serial data between devices
• SSL Application to Device Server(s) – Pass TCP sockets from an SSL enabled application to remote serial devices
• TruePort Version 5 to Device Server(s) – Pass serial application data from a host server with TruePort Version 5 to remote serial devices attached to IOLAN SDS device servers
• Secure Vmodem – Pass encrypted Vmodem ( Virtual Modem ) traffic between devices and a remote application that is designed to communicate with AT command based modems

Perle’s TruePort Version 5 used in conjunction with remote IOLAN SDS, STS or SCS device servers can also be used to enable existing serial applications to pass encrypted serial data across the network. TruePort Version 5 with SSL is available on with the following O/S’s;

• Microsoft Windows 2003, XP and 2000
• Linux
• Solaris
• AIX
• SCO Unixware
• SCO Openserver
• HP UX

An extensive feature set is included with Perle’s implementation of SSL;

• SSL V3.1 ( TLS V1.0 ) , SSL V3.0 and SSL V2.0 support
• Operate in either SSL Server or SSL Client mode
• Supported Encryption Ciphers : AES ( 256/192/128 ), 3DES, DES, RC4, RC2
• Configurable key lengths
• Hashing Algorithms: MD5, SHA-1
• X.509 Certificate Authentication: RSA, DSA
• Peer Validation Criteria: Country, State, Locality, Organization, Organization Unit, Common Name, Email
• Certificate Authorities ( CA ) list with digital signatures from companies such as Versign or self-signed certificates.
• Key Exchange: RSA, EDH-RSA, EDH-DSS, ADH