IT SECURITY Crypto products

SITLink Secure and confidential communication on leased lines

Photo 43627/1 Everyone is talking about mobile

communication, wireless around the

world using exorbitant bandwidths.

The leased line usually recedes into

the background when such solutions are discussed. But it is often forgotten

FIG 1 SITLink for confidential communication on synchronous leased lines up to 2 Mbit/s that the leased line is an approved

communication medium for transmit- Leased lines – omnipresent are also linked by ting large data quantities at low cost. more topical than ever this medium for instance. State-of-the- art communication networks are unimag- The purpose of SITLink is to provide Today, as most certainly in the future inable without leased lines, which dem- too, data are forwarded to modern com- onstrate their worth in numerous applica- confidential communication on such munication nodes through fixed terres- tions (see box on right). trial networks. Leased lines are still the transmission routes. most efficient means of data transmis- A permanent link is more economical sion between the concentration points. than a dial-up one if the traffic between In a state-of-the-art infrastructure, the two corporate sites exceeds a certain classic leased line or one of its modern volume. If the partners communicate variants, like the logical leased line in for more than 50 minutes per workday, SDH* networks or a PVC or S-PVC in a leased line is more attractive1), not ATM networks, is often used to set to mention other factors like integrated up a permanent link with remote part- data, speech and video, less time to set ners. The communication nodes of the up calls and reliable availability.

* Abbreviations: see box on right.

FIG 2 Data encryption on leased lines with SITLink SITLink

SITLink

SITLink SITLink

36 News from Rohde&Schwarz Number 169 (2000/IV) SITLink SITLink X.21

G.703

TDM

PABX G.703

G.703 (n x 64 kbit)

FIG 3 SITLink applications satellite and microwave links may be Great emphasis was placed during involved. As can be imagined, an enon- design on making the system virtually omical and reliable line does not really invisible to the user. Neither quality Leased lines at risk too offer the best information security and nor was to be degraded confidentiality. These factors make the by the extra functionality. After installa- As reliable and economical a permanent lines a target for espionage. The threat tion, the system operates transparently link may be, it is by no means resistant is often not taken very seriously, much to for the user and largely unnoticed by to attack. A leased line is usually the delight of intruders. the system. Operating and maintenance installed on a continuous basis and costs are significantly lower than with through fixed routes. The user is nor- other solutions at protocol (e.g IP) or mally unable to influence the media SITLink ensures confidentiality even application (e.g. e-mail) level. employed or the real route of the leased line once it is switched onto the public The powerful crypto algorithms of SITLink supports transmission rates up information highway. Contrary to public SITLink (FIG 1), a product of Rohde & to 2 Mbit/s and encrypts data without opinion, leased lines are not necessarily Schwarz SIT GmbH, make eavesdropping restricting bandwidth. The short latency the shortest physical connection as even on leased lines a fruitless enterprise. time of 0.5 µs guarantees uniform link Even intentional or inadvertent misrout- quality. Encryption is performed by the ing is almost impossible and would not SCA95 crypto chip, a hardware tool that Abbreviations reveal any information to a chance recipi- meets the most severe requirements. ent anyway. SITLink can be integrated ATM Asynchronous transfer mode into G.703 E1 lines and X.21 networks A management system for the security DCE Data circuit-terminating (FIGs 2 and 3). functions permits secured access to equipment DTE Data terminal equipment IP Internet protocol LSM Link security management Possible applications for leased lines PABX Private automatic branch exchange • Link-up of and of branch offices through PDH Plesiochronous digital and server-to-server link between the central gateway and firewall hierarchy headquarters and field office • Link between corporations and PSTN Public switched telephone (small corporate networking); production partners, call-up of network large corporate networking for inventory, placing of orders, PVC Permanent many sites access to databases S-PVC Soft or signalized • Simple LAN-to-LAN link • Link between editorial office and permanent virtual circuit • Video telephony and video con- printers for the transmission of SDH Synchronous digital hierarchy ferencing between corporate divi- print data, etc TDM Time division multiplex sions and subsidiaries, Internet

37 News from Rohde&Schwarz Number 169 (2000/IV) IT SECURITY Crypto products

Central site

V.24 Terminal server

V.24 V.24 FIG 4 V.24 Site B SITLink SITLink PC-based LSM for management and V.24 Terminal Server monitoring of secured leased lines SITLink

SITLink

SITLink SITLink SITLink Modem V.24 Remote Remote SITLink site B site A Site A

the installed systems. In addition to solutions for monitoring and managing 1) Cost analysis of Deutsche Telekom (see cost-saving in-band access, the system the security functions of a corporate http://www.telekom.de/angebot/datenkomm/ can also be monitored via a separate network. nutzberater/index.htm) network with greater fail-safety. Simple, Ronald Kuhls PC-based LSM (FIG 4) provides scalable

Reader service card 169/11

CD-ROM TIP Broadcasting

T&M Dream Team for sented through data sheets and And there is also a film on the Digital TV detailed information material. silver disk if you want to know more about Rohde & Schwarz in The title of the new In addition, the CD contains general. CD-ROM from demo versions of various test Rohde & Schwarz and analysis software tools. If All in all, the CD-ROM is sounds very promis- you want, you can test whether a recommendable compendium, ing. Behind it is the they are up to your requirements available free of charge from latest in test and in terms of operation and func- your local Rohde & Schwarz rep- measurement technol- tionality. “Documentation” holds resentative (PD 757.4447.43). ogy for digital tele- the entire operating manuals for Stefan Böttinger vision. The CD gives the DTV equipment. Fields of an overview of Rohde & application and practical use are Schwarz’s wide product range described in numerous technical for this market segment. The articles in pdf format. dream team mainly consists of generators and analyzers, pre-

38 News from Rohde&Schwarz Number 169 (2000/IV)