Radio Encryption Explained

Radio Encryption Explained

Radio encryption is used to keep the content of a radio transmission private. Instead of transmitting normal digital voice that any compatible receiver may be able to decode, an encrypted radio processes that information using an encryption algorithm and an encryption key before it is transmitted.

A radio with the correct encryption settings and key can decrypt the transmission and reproduce the original voice. A radio without the correct key may still detect that a transmission is taking place, but it will not normally be able to recover intelligible audio.

Encryption does not make a radio invisible. Someone with the right equipment can still potentially detect the transmission, determine what frequency is being used, and analyze other characteristics of the signal. Encryption protects the content of the communication, not the existence of the transmission itself.

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Analog Scrambling vs. Digital Encryption

Older analog radios sometimes use voice scrambling. This changes the audio so that it is difficult to understand on a normal receiver. Some forms of scrambling can discourage casual monitoring, but they generally do not provide the same level of security as modern digital encryption.

Digital radios convert voice into digital data before transmitting it. That digital information can then be encrypted before being sent over the air. Depending on the radio, this may include basic digital privacy, manufacturer-specific encryption, AES-128, AES-256, or another encryption method.

Not all types of encryption provide the same level of security, and not every encrypted radio will work with another encrypted radio.

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What Is AES?

AES stands for Advanced Encryption Standard. It is a widely used encryption standard that can use different key sizes, including 128-bit, 192-bit, and 256-bit keys.

AES-256 is commonly found in professional communications equipment and is one of the stronger encryption options available on commercial digital radios.

However, two radios advertising AES-256 are not automatically compatible with one another. The manufacturer, firmware, digital protocol, key format, and the way encryption is implemented can all affect interoperability.

If encrypted communications between different radio models or manufacturers are required, compatibility should be confirmed before purchasing equipment.

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What Is an Encryption Key?

The encryption key is the information used by the radio to encrypt and decrypt communications.

Radios that are supposed to communicate with one another securely need compatible encryption settings and the correct key. If one radio has the wrong key, it will not be able to properly decrypt the transmission.

Many commercial radios can store multiple encryption keys. This allows different channels, talkgroups, departments, or teams to use separate keys when needed.

Encryption keys should be treated as sensitive information. If a radio is lost, stolen, or otherwise compromised, it may be appropriate to change the key used by the rest of the system.

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What Is Required for Encrypted Radios to Work Together?

Encryption is only one part of a radio system.

The radios still have to be programmed correctly in order to communicate. Depending on the system, that may include the correct frequency, digital mode, channel settings, DMR color code, time slot, talkgroup, encryption type, and encryption key.

A mismatch in any of those settings can prevent radios from communicating even if both radios support encryption.

This is why it is usually better to design and program the radios as a complete system rather than buying several different models simply because each one lists encryption as a feature.

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Does Encryption Affect Range?

Encryption itself normally does not have a meaningful effect on radio range.

Range is much more dependent on transmit power, frequency, antenna performance, antenna height, terrain, buildings, vegetation, interference, receiver quality, and whether repeaters or other infrastructure are being used.

An encrypted five-watt handheld does not suddenly have more or less RF range simply because encryption is enabled.

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Can Someone Still Monitor an Encrypted Radio?

They may be able to detect the radio signal, but that does not mean they can understand the communication.

A receiver may show activity on the frequency or identify that a digital transmission is taking place. Without the proper encryption information, properly encrypted voice traffic should not reproduce as normal intelligible speech.

Encryption also does not prevent radio direction finding. A transmitting radio is still producing RF energy that can potentially be detected or located.

For that reason, encryption should be considered one part of communications security rather than a complete solution by itself.

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Key Management

Encryption is only as useful as the way the keys are managed.

Organizations using encrypted radios should keep track of which radios contain which keys, limit unnecessary distribution of encryption information, protect programming files and codeplugs, and have a plan for changing keys if a radio is lost or compromised.

Separate keys can also be used for different teams or groups when the equipment supports it.

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Do You Need a License?

Owning a radio that supports encryption and being authorized to transmit with it are two separate issues.

The frequencies and radio service being used determine what rules apply.

Many professional and commercial radio systems operate under FCC Part 90 licensing. Part 90 systems can support digital voice and encryption when the system is properly licensed, authorized, and configured.

Other radio services have different restrictions. GMRS, for example, does not allow messages that are coded or transmitted with hidden meanings, so encryption should not be used to conceal normal GMRS voice communications. Amateur Radio also generally prohibits transmissions encoded for the purpose of obscuring their meaning.

Before deploying an encrypted radio system, the appropriate frequencies, equipment, licensing, and operating rules should be determined for the intended use. Contact Pollux Field Systems today and we will help you navigate the licensing process.

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Building the Right Radio System

Encryption is useful, but it is only one feature of a properly designed communications system.

The radios still need to fit the environment they will be used in, provide adequate coverage, support the required accessories, work with any repeaters or infrastructure being used, and be programmed so that every radio in the system works together.

Pollux Field Systems can assist with analog and digital radio selection, DMR systems, encryption-capable radios, AES-capable radio platforms, radio programming, custom codeplugs, interoperability, repeaters, antennas, accessories, and communications planning.

If you are trying to build a secure radio system and are not sure what equipment or programming you need, contact Pollux Field Systems with the number of users, expected operating area, and what you are trying to accomplish.

Communications. Connectivity. Confidence.