P25 Encryption Explained: What It Is and Why It Matters
P25 is the modern standard for police radio systems. It supports encryption—but encryption is optional. Understanding this technology reveals why going dark is a policy choice, not a technical necessity.
What Is P25?
P25 (Project 25) is a set of standards for digital two-way radio communications, developed primarily for public safety use. It's the modern replacement for older analog radio systems.
Key Facts About P25
- Developed by: Association of Public-Safety Communications Officials (APCO) and federal agencies
- Primary users: Police, fire, EMS, federal law enforcement
- Purpose: Interoperability between agencies, better audio quality, efficient spectrum use
- Encryption: Supported but not required
P25 was designed to solve real problems: agencies couldn't communicate with each other during emergencies, analog systems had poor coverage, and the radio spectrum was congested. It succeeded at these goals.
What P25 was not designed for was hiding police activities from the public. Encryption was added as an option for legitimate sensitive operations—but many departments now use it for everything.
How P25 Systems Work
Digital Voice
Voice is converted to digital data before transmission. This provides clearer audio, better coverage, and more efficient use of radio frequencies.
Trunking
Multiple talk groups share a pool of frequencies. A computer automatically assigns channels, allowing many users to share limited spectrum.
Interoperability
Different agencies can communicate directly. Police, fire, and EMS can coordinate during emergencies without radio compatibility issues.
Optional Encryption
P25 supports AES-256 encryption—but it's a setting that can be turned on or off. Many systems operate entirely "in the clear."
P25 Encryption: The Technical Details
How AES-256 Encryption Works
When P25 encryption is enabled, audio is scrambled using the Advanced Encryption Standard (AES) with 256-bit keys:
- Officer speaks into radio
- Voice is digitized (converted to data)
- Data is encrypted using the department's key
- Encrypted data is transmitted
- Only radios with the same key can decrypt and play the audio
Why AES-256 Is Unbreakable
AES-256 is the same encryption standard used by:
- U.S. military for classified communications
- Banks for financial transactions
- Governments worldwide for top-secret data
The number of possible 256-bit keys (2^256) exceeds the number of atoms in the observable universe. Even with every computer on Earth working together, trying all possible keys would take longer than the age of the universe.
No consumer device, software, or "decoder" can break this encryption. Anyone claiming otherwise is selling a scam.
The Critical Point: Encryption Is Optional
P25 Works Just Fine Without Encryption
This is the most important thing to understand: P25 systems can operate encrypted or unencrypted. The same radios, the same infrastructure, the same technology—just with encryption turned off.
When departments claim they "had to" encrypt because they upgraded to P25, they're being misleading. P25 doesn't require encryption. They chose to enable it.
P25 "In the Clear"
Unencrypted Mode
- All benefits of digital audio quality
- Full interoperability between agencies
- Efficient spectrum use
- Public can monitor with digital scanners
- Journalists can report in real-time
- Transparency and accountability maintained
Used by: Many departments nationwide who value transparency
P25 Encrypted
AES-256 Encryption Enabled
- Same digital audio quality
- Same interoperability (with shared keys)
- Same spectrum efficiency
- Public completely blocked
- Journalists dependent on press releases
- Accountability mechanisms eliminated
Used by: Departments that prioritize secrecy over transparency
Why Do Departments Choose to Encrypt?
If P25 works fine without encryption, why do departments enable it? Their stated reasons often don't hold up to scrutiny.
Claim: "Officer Safety"
"Criminals use scanners to ambush officers."
Reality:
Zero documented cases of scanner-related officer harm in decades of public scanning. This is a theoretical fear, not an evidence-based concern.
Claim: "Victim Privacy"
"Sensitive information goes over the radio."
Reality:
Hybrid systems can encrypt sensitive channels while keeping routine dispatch open. Mobile data terminals already handle private information.
Claim: "Operational Security"
"Criminals monitor investigations."
Reality:
Tactical channels for sensitive operations have always been available. Routine patrol doesn't require secrecy.
Claim: "Technology Upgrade"
"Encryption comes with new systems."
Reality:
P25 encryption is a setting that can be disabled. Many departments use P25 without encryption. The "upgrade" excuse is misleading.
The Pattern Suggests a Different Motivation
Encryption accelerated dramatically after 2020, when scanner access during protests revealed police misconduct, racist remarks, and coordination of aggressive tactics. The timing strongly suggests encryption is about controlling information, not safety.
Read the full evidence analysis →The Policy Choice: Technology Enables, Policy Decides
Encryption Is Not Inevitable
P25 technology gives departments a choice. They can:
- Operate fully open: All channels unencrypted, full public access
- Use hybrid systems: Encrypt tactical/sensitive channels, keep dispatch open
- Encrypt everything: Complete blackout on all police communications
The technology doesn't force any particular choice. When a department encrypts, they're making a policy decision about transparency—one that can be challenged and reversed.
Departments That Chose Transparency
Many departments using modern P25 systems have chosen to remain unencrypted. They enjoy all the benefits of digital radio while maintaining public trust through transparency.
Some departments that initially encrypted have reversed course after community pressure. Encryption policies are not permanent—they respond to public demand.
See transparency success stories →What You Can Do
Demand Transparent P25 Policies
- Check your department's status — Is encryption on or off? For which channels?
- Attend public meetings — Encryption decisions should involve community input
- Request justification — FOIA the evidence used to justify encryption
- Advocate for hybrid systems — Protect privacy without blanket encryption
- Support legislation — Back laws requiring transparency in P25 deployments
Take Action for Transparency
Your voice matters. Here are concrete ways to advocate for open police communications in your community.
Contact Your Representatives
Use our templates to email your local officials about police radio encryption policies.
Get StartedRead Case Studies
See how encryption has affected real communities - from Highland Park to Chicago.
View CasesSpread Awareness
Share evidence about police radio encryption with your network and community.
Public Testimony
Learn how to speak effectively at city council and public safety meetings.
Prepare to Speak