Browse Prior Art Database

HIGH SECURITY ENCRYPTED MOBILE DATA

IP.com Disclosure Number: IPCOM000008079D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-16
Document File: 2 page(s) / 81K

Publishing Venue

Motorola

Related People

Mark Chapman: AUTHOR [+2]

Abstract

APCO's published methods for insuring conti- dentiality of data sent through the system, either mobile unit to mobile unit or mobile unit to fixed host, does not protect against any of the common methods of cryptographic attack. In particular the defined APCO system permits the same message to be sent inbound in the clear and outbound encrypt- ed. This allows one of the easiest cryptographic attacks.

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@ MOTOROLA Technical Developments

HIGH SECURITY ENCRYPTED MOBILE DATA

by Mark Chapman and Ray Van Tassle

INTRODUCTION

   APCO's published methods for insuring conti- dentiality of data sent through the system, either mobile unit to mobile unit or mobile unit to fixed host, does not protect against any of the common methods of cryptographic attack. In particular the defined APCO system permits the same message to be sent inbound in the clear and outbound encrypt- ed. This allows one of the easiest cryptographic attacks.

Also, the APCO system provides encryption for only the over-the-air link.

  While the data messages are on the land-line infrastructure, they are tin-encrypted. This poses a security problem in a system with multiple RNC's (Radio Network Controller), which communicate between themselves via a standard IP network.

METHOD

  In normal mode, the RNC receives a packet from the landline IP network, encrypts it, then sends to the mobile radio over RF. Likewise, it receives a packet on the RF from a mobile radio, decrypts it if it is encrypted, and sends it to the landline IP net- work. Operating in this manner, all outbound pack- ets to a mobile radio are encrypted automatically, without the necessity of the originating IP host hav- ing (or being able to) take any special action.

  For high security, the packets must stay encrypt- ed. Ideally, the RNC would not even be capable of decrypting such a packet. In this method the send- ing mobile will encrypt the entire...