GSMK from Berlin, has developed the CryptoPhone, a GSM 900/1800 capable device, that connects to your Pocket PC. It uses AES256 and Twofish encyrption technologies. The 4096 bit Diffie-Hellman key exchanges with an SHA256 hash function.
GSMK claims to be the only producer of an encrypted mobile telephone with open source code. People can verify there are no ‘back doors’ in the code. Publication of source code does not compromise security.
The CryptoPhone will be less then other devices of this calibre, only $1,800, and can be shipped in a security sealed box direct from the manufacturer. This is to ensure the telephones are not tampered with along the way.
Secure Talk time will run you about 3 hours and 15 minutes.