Part of our Emergency Communications and Preparedness guide.
Under FCC Part 97.113, you cannot transmit messages encoded for the purpose of obscuring their meaning. Even though some radios technically can do it, true encryption (like AES-256) on amateur frequencies is a no-go. It’s no different than a car being able to go 180 mph while the highway speed limit caps you at a fraction of that.
That doesn’t mean you can’t technically do it. It means it’s against the FCC rules and could result in fines or worse. So let’s talk about private vs. secure vs. obscure comms.
COMSEC vs. OPSEC: Where the Legal Line Actually Sits
Communications Security (COMSEC), meaning keeping your data secret, is off the table. But if you’re talking about Operational Security (OPSEC), signal obscurity, or data integrity, there is actually a lot you can do legally. Here’s exactly how “security” works across analog, digital voice, and data modes on the ham bands.
Analog: Zero Technical Confidentiality
On analog (FM/SSB), there is zero technical confidentiality. Anyone with a $25 Baofeng or a Software Defined Radio (SDR) dongle can hear you. Voice inversion scramblers are illegal on ham bands because their sole purpose is to obscure the audio. Here’s how to add discipline legally:
- Brevity Codes & PACE Planning: You don’t hide the signal, you hide the meaning. Using pre-arranged grid locations, custom brevity codes (“Status Blue at Point Echo”), or a strictly timed PACE plan (Primary, Alternate, Contingency, Emergency frequency rotations) keeps casual eavesdroppers clueless.
- Terrain & Power Management: Drop your power to the absolute minimum required to make the contact (QRP), and use directional beam antennas or local topography (like a hill or ridge) to mask your footprint. If the signal doesn’t reach the bad guys, they can’t decode it.
- Band Selection (220 MHz): The 1.25-meter (220 MHz) band is another great option for obscurity. Far fewer radios on the market support it, so simply operating there screens out most casual listeners who don’t even own a radio capable of receiving it. Here’s a closer look at why the 220 MHz band is worth adding to your kit.
Digital Voice (DMR, P25, System Fusion): Security by Obscurity
Commercial digital radios have massive encryption capabilities built right in, like ARC4 or AES. However, turning those keys on while operating under your ham license is a fast track to losing it. Here’s how to do it legally:
- The Codec Barrier: When you speak into a DMR or Yaesu Fusion radio, your voice is converted to digital data using specific vocoders (like AMBE+2). While this isn’t encryption, it creates a massive layer of practical obscurity. A casual scanner listener or someone with an old analog radio will only hear raw digital “buzzing.” Keep in mind that roughly 75% of the radios in people’s hands are analog only, so just using digital limits their ability to even hear you, even without unique codecs or encryption.
- Talkgroups and Color Codes: By using specific digital color codes, time slots, and niche talkgroups (TG), you effectively segment yourself away from 99% of casual traffic. Just remember: anyone with a digital hotspot or a properly configured SDR can still monitor and decode your audio if they tune in.
Data Modes: The Gold Standard for Integrity
This is where it gets really interesting. While you cannot encrypt data payloads (like sending an encrypted PGP email over Winlink), you CAN use cryptography for authentication and integrity. Here’s how to do it legally:
- Cryptographic Signing: The FCC bans obscuring the meaning of a message, but it does not ban proving who sent it. You can legally use cryptographic signatures (like signing a tactical packet text with a key). The message stays completely open and readable by anyone, but it prevents spoofing. No one can pretend to be your station because they can’t forge your signature.
- Digital Mode “Hiding”: Running text or files over highly specialized digital modes like Vara HF/FM, JS8Call, or old-school packet radio requires specific software and hardware to decode. It won’t stop a dedicated operator from seeing your text, but it filters out the general public.
- Mesh Networks (AREDN / Mesh): If you’re running high-speed multimedia data over amateur frequencies (like modified Wi-Fi gear), you have to disable standard WPA2/WPA3 encryption to comply with Part 97. Instead, hams use open nodes but protect their network infrastructure using SSL/SSH with null ciphers (cleartext data) combined with cryptographic key authentication, so you can log in safely without exposing passwords.
Bottom Line
For more on the modes mentioned here, see What Is JS8Call?, What Is Winlink?, and Setting Up Your First Meshtastic Node.
If you want 100% private, military-grade encrypted tactical chat and want to stay legal, go apply for a commercial Part 90 license, use ISM bands (like Meshtastic/LoRa), or stick to Signal on your cell phone. But if you want to practice smart, resilient, and highly disciplined operations within the bounds of the law, amateur radio gives you an incredible sandbox to learn in with a small group of friends.