By: Sirran  05/12/2011
Keywords: secure communications, Cellular Communications

MobileCrypto is a hardware and software-based SECURE Communications solution that protects GSM cellular communications with a unique SECURE authentication service and advanced end-to-end encryption software. When combined with SIMcrypto, a patented secure mobile authentication solution from SiRRAN, MobileCrypto is capable of ensuring that ALL mobile voice and SMS communications as well as data-at-rest within a mobile device, is fully protected.

Designed specifically for Windows Mobile phones, MobileCrypto offers security against any attempts to intercept active communications both from inside a telephone network as well as over-the-air.

Who intercepts Cellular traffic?

Tapping and storage of all calls is standard procedure in many countries, and access to the collected data is all too often subject to varying interests and objectives. Storage has become so cheap that it is no longer a significant cost factor and literally every call and text message can be stored over many years, due to advances in archiving technology this information can be easily accessed by the relevant agencies. Cable taps on undersea and land fibre trunks provide interception points for entire countries and continents, also Satellite interception, both strategic (at satellite ground stations) and tactical (over-the air interception of satellite terminals in the vicinity) is also popular and used by different types of adversaries depending on target vicinity and mission objectives.

Contrary to common belief, VoIP traffic is subject to even greater confidentiality and privacy risks than “classical” circuit-switched phone calls. Intercepting “classical” circuit-switched phone calls requires either physical (or radio) access to the phone line to be tapped, or access to a switch A wire tap on a specific phone line can be discovered, and physical access to classical telephone switching centers and PBX’s is relatively restricted. In contrast, with VoIP, calls are generally out on the wide-open Internet, offering infinitely more ways for eavesdroppers to intercept and record calls. Running standard packet sniffer or protocol analyzer software on any laptop or other device attached to a VoIP network segment allows everyone with hardly more than the most basic computer skills to identify and capture all voice traffic. Many corporate VoIP systems implement hardly any authentication checks, meaning that it is possible for an attacker to re-route traffic by means of, e.g., ARP flood attacks on IP switches or by assigning false subnet masks and router addresses.

Secure Cellular

SiRRAN’s MobileCrypto solution enabled military, law enforcement and government personnel to protect confidential conversations and vital information from being accessed by unwanted parties. The technology is based on published and well-researched encryption algorithms as well as a patented user/device authentication process.

MobileCrypto encrypts active SECURE calls with AES and Twofish, each cipher having a block size of 128-bits and a key size of 256-bits. The solution uses these algorithms simultaneously as well as a 4096-bit Diffie-Hellman shared secret exchange to authenticate each call/device/user, in order to provide multiple-layers of security and an effective "fall back" inside the crypto-system design.

To prevent man-in-the-middle attacks, a six-letter hash is generated from the 4096-bit Diffie-Hellman shared secret exchange and displayed to the user. Each user then reads three letters over the encrypted line to the communication partner to verify a secure link. If there is any discrepancy in the six letters, a man-in-the-middle attack has been detected and a new call should be established.
A completely new session key is generated for each secure voice call, and no key material for an encrypted call is stored anywhere on device. Additionally, secure storage capability of the MobileCrypto software protects confidential contact information, messages, and notes.

Additional man-in-the-middle protection is provided by SiRRAN’s SIMcrypto application. SIMcrypto provides active surveillance, within the PSTN core; of SECURE packets to ensure call integrity is kept at all times. (See SIMcrypto for additional details.)

MobileCrypto Features:

  • Simultaneous 256-bit encryption (AES, Twofish) of SECURE calls
  • Unique 4096-bit Diffie-Hellman shared secret exchange for each SECURE call
  • Device Session Wipe (DSW) feature ensures that at call ending, all parameters of the call are wiped from memory with no way to reconstruct the code used of the content of the call.
  • Non-secure calling option
  • Secure Storage encrypts contacts and messages
  • Verifiable Security with six-letter hash generation for man-in-the-middle detection
  • Simple Management interface
  • FIPS 140-2 Certified
  • SIMcrypto integration for Dual IMSI capability on a single SIM / GSM phone

Keywords: Cellular Communications, secure communications

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