There is one simple rule of telephone security:
Never say anything on the telephone that you would not want your worst enemy to hear.
Landline telephones are pathetically simple to tap. Almost all mobile phone systems utilize security systems which have been compromised. VoIP telephone calls can be tapped by anyone with access to the network.
In addition, you don’t know the environment of the person on the other end of a telephone conversation. Perhaps someone is pointing a gun at them, or perhaps they are talking on a mobile phone while standing in line at a bank, or maybe someone in hiding is pointing a parabolic microphone directly at them.
What NEVER To Say on the Telephone
- Where you are
- Where you are going
- What path you will take
- When you will return
Never give your name or any other information to an unknown caller. Never take telephone surveys. Never stay on the line with an unknown caller. The caller may be trying to social engineer information out of you, he may be attempting to triangulate the position of your mobile phone, or he may be trying to keep you in one place. It is safer to rob someone’s home or office if you know they are talking on the telephone, distracted, unmoving, and not able to hear background noises.
End-to-End Encrypted Telephone Communication
You cannot rely upon the security provided by a telephone carrier, no matter whether it is a landline, mobile, or VoIP carrier. Secure telephone communications requires end-to-end encryption. This means that the telephones on both ends of the communication must provide compatible encryption methods — usually this means that they must be from the same manufacturers.
High-encryption GSM mobile telephone handsets are available from vendors such as Safe-com, Adeya, GoldLock, and Cryptophone. VoIP encryption software is available from vendors such as Zfone. Encrypted landline telephones are also available from a variety of manufacturers.
If you must speak on the telephone, end-to-end encryption is the only means of ensuring that you can do so privately. However, keep in mind that the telephone companies will still know who you called and when — as will anyone with access to the telephone companies databases.
Ensuring Communications Availability
A determined attacker will begin by cutting your telephone lines. The mobile version of this is using one or more cell phone jammers to prevent your mobile handset from communicating. Blocking VoIP calls is usually as easy as cutting the cable TV or DSL line over which the VoIP calls are transmitted.
Having multiple backup communication paths, such as satellite, business band, HAM radio, CB radio, or GPRS can provide additional security, but the general rule is that calling for help is a luxury — a luxury which you may not have.