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Crypto phones
Secure telephone equipment

Secure telephones are telephones that provide some level of voice security, in order to protect the calling parties from eavesdropping. Crypto phones are a special type of secure telephones that use advanced digital techniques for the encryption of voice data. Depending on the type and level of encryption used, crypto phones may be restricted or classified items.

Computer algorithms for government and military use, are generally controlled by the National Security Agency (NSA) in the US. They are divided into several security levels, of which Type 1 represents the highest level of security. Such devices can safely be used for top secret messages.

Secure telephones on this website
SIGSALY secure telephony system (Ciphony I)
British WWII scrambler phone (also known as Frequency Changer and as Secraphone)
Frequency Changer No. 6AC/3 - British wartime telephone scrambler as used by Churchill
German WWII phone scrambler
High-end portable telephone encryptor
KY-3 wideband secure voice system with KYX-9 desk set
Secure Telehone Unit STU-I (KY-70)
Secure Telehone Unit (ITT, Northern Telecom)
Motorola STU-II/B SECTEL (NATO-version)
Secure Telehone Unit (Motorola, AT&T, RCA, etc.)
Motorola STU-III/R
Secure Terminal Equipment
Motorola SECTEL range of secure telephones
AT&T/Lucent 1100 STU-III secure phone (later sold by General Dynamics)
CVAS III Secure Telephone
Digital Subscriber Voice Terminal
Philips Spendex-40 secure telephone for voice, fax and computer
Philips Spendex-50, military secure crypto phone (a.k.a. DBT)
Philips PNVX secure crypto telephone
TCE-500, secrure crypto telephone
Racal MA-44741 Secure Phone Adapter
Simple digitially controlled analogue voice scrambler
AT&T TSD-3600 Telephone Encryptor
AT&T/Lucent 4100 crypto phone (later sold by General Dynamics)
GE/RCA STU-III third generation secure telephone unit
The Siemens DSM Voice telephone encryptor
Siemens Crypset 100 crypto phone
Hagelin (Crypto AG) HC-3300 crypto phone
Hagelin HC-4220 Fax Encryptor
Hagelin HC-2203 PSTN Phone Encryptor
Mieco 25A telephone scrambler
Telsy TDS-2003 portable voice encryptor
Telsy TDS-2004 telephone voice encryptor
Telsy Cryptophone 7000
Racal MA-4430 crypto telephone
Terma ET-10, Digital Tactical Terminal with secure voice and data capability
Siemens CTE-020 Remote Digital Engineering Order-Wire Terminal
Tele Security Timmann, TST-7700 Voice and data encryption system
Gretacoder 101, speech scrambler
Mobile frequency and time domain voice scrambler
Elcrovox 1-4D narrow band voice and data terminal (STU-II compatible)
Rohde & Schwarz Elcrodat 6-2
Not truely a crypto phone, but usable on crypto-enabled telephone exchanges
Secure GSM phone
GSMK CryptoPhone IP-19
E-20 PSTN crypto telephone
Raytheon IST-2 secure telephone
CIS Secure DTD-7962-T2 TEMPEST version of Cisco 7962G Unified IP Phone
vIPer Universal Secure Phone
SINA Communicator H
SINA Communicator H (red)
Secure Fax Gateway for crypto telephones
French mechanical Cryptophone by Jules Carpentier (1919)
Voice scramblers
Older types of secure telephones generally use a technique called frequency inversion. They are sometimes called scramblers and are inherently insecure. An example of such a scrambler phone is the Mieco 25A (shown above). Even voice scramblers that use time-division speech scrambling should be considered insecure by today's standards, even when the two techniques are combined.

 More about scramblers

Further information
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Crypto Museum. Created: Wednesday 07 December 2011. Last changed: Sunday, 14 April 2024 - 10:29 CET.
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