San Diego Police Implements Full Radio Encryption, Ending Decades of PublicAccess

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San Diego Police Implements Full Radio Encryption, Ending Decades of PublicAccess

Multi-million dollar upgrade affects media coverage and community oversight of law enforcement activities

By [SD Independent Tech Reporter] | June 4, 2025

SAN DIEGO — The San Diego Police Department completed its transition to fully encrypted radio communications this week, effectively ending nearly a century of public and media access to real-time police dispatches across the city.

The move, which took effect Monday, represents one of the largest implementations of police radio encryption in California and affects one of the state's most populous jurisdictions. The change impacts not only the City of San Diego but coordination with the County Sheriff's Department, which oversees unincorporated areas throughout San Diego County.

Million-Dollar Technology Overhaul

The encryption implementation required a massive technology upgrade that cost the department millions of dollars. SDPD replaced approximately 3,400 handheld radios and upgraded about 1,050 mobile radios in its vehicle fleet to support the new encrypted communications system.

"This transition ensures SDPD can fully meet the DOJ's requirements without compromising officer or public safety," the department said in a statement. "Our new encrypted channels will also use a higher level of encryption than our current inquiry channel, ensuring information shared is well protected."

The department's new system utilizes Project 25 (P25) digital radio technology with Advanced Encryption Standard (AES) 256-bit encryption, considered the gold standard for public safety communications security.

Compliance with State and Federal Mandates

The encryption rollout comes in response to a California Department of Justice directive issued in October 2020 requiring law enforcement agencies to protect personally identifiable information (PII) transmitted over radio frequencies. The mandate was reinforced by federal FBI Criminal Justice Information Services (CJIS) Security Policy requirements that took effect in December 2022.

"Communications regarding incidents and checks on personal information, such as driver's licenses or criminal history, will now occur on encrypted channels," explained SDPD Communications Director Maria Rodriguez. "This protects the privacy of victims, witnesses and suspects when their personal information is transmitted over law enforcement radio."

The information that must now be protected includes Social Security numbers, addresses, phone numbers, and medical and mental health conditions and histories — data that was previously transmitted in the clear and could be monitored by anyone with a police scanner.

End of an Era for Media and Public Monitoring

The encryption effectively ends a practice that dates back to the early days of radio technology, when news organizations, emergency responders, and concerned citizens could monitor police activities in real-time using commercially available scanners.

Local news stations have relied on scanner monitoring for decades to quickly respond to breaking news events, accidents, and public safety incidents. KGTV reporter Jennifer Kastner said the change will significantly impact how news organizations cover breaking stories.

"We've used scanners to identify major incidents as they develop — everything from structure fires to traffic accidents to active crime scenes," Kastner explained. "Without that real-time access, there will be delays in getting information to the public during critical situations."

The San Diego Union-Tribune's public safety reporter Mike Chen echoed those concerns: "Scanner traffic has been invaluable for ensuring the public gets timely, accurate information about incidents that could affect their safety or commute. This encryption creates an information gap that will be difficult to fill."

Operational Impacts on Law Enforcement

For SDPD officers and dispatchers, the transition represents a significant operational change. The department's 2,000+ sworn officers and civilian personnel have undergone extensive training on the new encrypted systems.

Sergeant Lisa Park, a 15-year SDPD veteran, noted both benefits and challenges of the new system. "The encryption definitely provides better security for sensitive information, but it requires more careful channel management," she said. "We have to be more deliberate about which channel we're using for different types of communications."

The system allows officers to communicate securely during tactical operations and sensitive investigations without concern that suspects or others might be monitoring radio traffic. However, it also requires more complex coordination for multi-agency responses involving departments that may not have compatible encryption keys.

Complex Key Management Operations

One of the most significant operational challenges of the new encrypted system involves managing the cryptographic keys that enable secure communications across SDPD's extensive radio network. With over 4,450 radios now requiring encryption keys, the department has had to develop sophisticated protocols for key distribution, rotation, and security.

"Key management is probably the most complex aspect of this entire transition," explained SDPD IT Director Robert Chen. "We're not just talking about passwords here — these are sophisticated encryption keys that must be carefully controlled and regularly updated to maintain security."

The department has implemented an Over-The-Air Rekeying (OTAR) system that allows encryption keys to be updated remotely without requiring physical access to each radio. However, the system requires constant monitoring to ensure all radios receive updated keys, particularly challenging given the department's 24/7 operations across multiple shifts.

"OTAR still has an administration overhead to track down and follow-up on any problem radios that could not be rekeyed," Chen noted. "This is common where multiple shifts, spare radios, and specialist vehicles mean radios are not powered on and active on the radio system all of the time."

The department has hired two additional IT specialists specifically dedicated to encryption key management, at an annual cost of approximately $180,000 in salaries and benefits. These personnel are responsible for generating new keys, monitoring key distribution, and responding to security incidents involving lost or compromised radios.

Security protocols for lost or stolen radios have become particularly complex. When a radio goes missing, the entire encryption key must be changed across all radios that shared that key — a process that can take hours and temporarily disrupt communications during the transition.

"If an officer's radio is stolen or goes missing, we can't just deactivate that one device," explained Sergeant Maria Torres, who oversees radio communications training. "We have to assume the encryption key is compromised and update keys on potentially hundreds of other radios to maintain security."

The department maintains multiple encryption keys for different operational purposes — separate keys for routine patrol operations, tactical teams, and inter-agency communications. This multi-key approach enhances security but adds layers of complexity to daily operations.

Regional Coordination Challenges

San Diego County's law enforcement landscape includes multiple agencies — from the San Diego Sheriff's Department covering unincorporated areas to smaller municipal departments in cities like Chula Vista, Oceanside, and Escondido. Ensuring interoperability across these agencies while maintaining encryption has required extensive coordination.

"Nearly all law enforcement agencies across Southern California have already adopted encrypted radio technology to meet this standard," SDPD noted, suggesting that regional coordination has improved as more departments implement similar systems.

The San Diego Sheriff's Department, which provides law enforcement services to unincorporated areas of the county and contracts with several smaller cities, implemented its own encryption system earlier this year. The department spent approximately $2.3 million on radio system upgrades to comply with state and federal requirements.

Community and Transparency Concerns

Civil liberties advocates have expressed concern about the impact of encryption on police transparency and accountability. The American Civil Liberties Union of San Diego & Imperial Counties released a statement questioning whether the encryption goes beyond what's necessary to protect personal information.

"While we understand the need to protect individuals' private information, we're concerned that full encryption could reduce transparency and accountability in police operations," said ACLU attorney David Loy. "For nearly 90 years, the public and press have had access to police radio communications as an important check on law enforcement activities."

Community activists have pointed to the timing of the encryption rollout, which comes amid ongoing discussions about police reform and community oversight. Some have called for the city to explore hybrid systems that protect sensitive information while maintaining public access to general dispatch communications.

Alternative Information Channels

To address transparency concerns, SDPD has committed to enhancing other communication channels with the public. The department's social media presence has expanded significantly, with more frequent updates on Twitter and Facebook about significant incidents and public safety alerts.

The department has also upgraded its website to provide more detailed crime mapping and statistical information. Additionally, SDPD plans to implement a new public information system that will provide near real-time updates on major incidents, though details of this system have not yet been finalized.

"We remain committed to transparency and keeping the community informed about public safety matters," said SDPD Chief David Nisleit. "While radio encryption is necessary for compliance and security, we're exploring new ways to ensure the public stays informed about incidents that affect them."

Cost-Benefit Analysis

The financial investment in encrypted communications represents one of the largest technology upgrades in SDPD's recent history. Beyond the initial equipment costs, the department faces ongoing expenses for encryption key management, system maintenance, and personnel training.

However, department officials argue the investment pays dividends in officer safety and information security. "The protection of sensitive information and the operational security benefits justify the investment," said Deputy Chief John Martinez. "We can't put a price on officer safety or the privacy rights of the individuals we encounter."

The department estimates the new system will have a useful life of approximately 10-15 years, with periodic upgrades required to maintain compatibility with evolving standards and technology.

Looking Forward

As San Diego joins the growing number of California law enforcement agencies using fully encrypted communications, the long-term impacts on community relations, media coverage, and public safety remain to be seen.

State legislators continue to debate whether current encryption practices strike the right balance between privacy protection and public transparency. Senator Josh Becker's attempts to require alternatives to full encryption have so far been unsuccessful, but the issue remains active in Sacramento.

For now, San Diego residents and news organizations will need to adapt to a new reality where police radio communications are no longer part of the public domain. The change marks the end of an era in police-community transparency while ushering in what law enforcement officials say is a more secure and privacy-conscious approach to public safety communications.

The San Diego Police Department's transition to encrypted communications affects approximately 1.4 million city residents and represents the latest major California law enforcement agency to implement full radio encryption in compliance with state and federal privacy mandates.

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SIDEBAR: How Police P25 Radios Compare to 5G Cell Phones

Technical analysis reveals fundamental differences in design philosophy and performance

When San Diego police officers communicate over their encrypted P25 radios, they're using technology that might seem antiquated compared to the 5G smartphones in their pockets. However, these systems are engineered for entirely different purposes, with performance characteristics that highlight why law enforcement can't simply rely on commercial cellular networks for mission-critical communications.

The Ruggedized Smartphone Question

"Couldn't police just use ruggedized smartphones on a dedicated network?"

This question touches on one of the most active areas in public safety communications. Ruggedized smartphones do exist and are increasingly sophisticated:

Current Ruggedized Options:

• Sonim XP10: Ultra-rugged 5G smartphone with FirstNet certification, MIL-STD-810G compliance, IP68 rating
• CAT S62 Pro: Thermal imaging camera, IP68/IP69 rating, drop-tested to 1.8 meters
• Motorola/Zebra Devices: Purpose-built for enterprise and public safety use

However, even the most rugged smartphones face limitations compared to purpose-built P25 radios:

Durability Comparison:

• P25 Radios: Designed for 10-15 year operational life, field-replaceable batteries, MIL-STD-810 across all variants
• Ruggedized Smartphones: 2-3 year replacement cycles, integrated batteries, variable durability standards

"The Sonim XP10 is impressive, but it's still fundamentally a smartphone trying to do radio work," explains Bob Escalle, VP of Public Safety at Sonim Technologies. "We see it as augmenting radios, not replacing them entirely."

FirstNet: The Dedicated Network Reality

"What about running smartphones on a separate, dedicated network?"

This is actually happening through FirstNet, the nationwide public safety broadband network built by AT&T:

FirstNet Specifications:

• Dedicated Spectrum: 700 MHz Band 14 (20 MHz) reserved exclusively for public safety
• Priority Access: Public safety traffic preempts commercial users during emergencies
• Coverage Goals: 99.8% of population, 77.2% of geographic coverage in California
• Reliability Target: 99.99% uptime (but less than well-designed P25 systems)

Current FirstNet Limitations:

• Coverage Gaps: Still relies on AT&T commercial network in many areas
• Mission-Critical Voice: Not yet fully ready for primary voice communications
• Latency Issues: Cellular encode-to-decode latency approximately 2,100 ms vs P25's maximum 500 ms across systems

Hybrid Approaches: The Future is Here

The industry is moving toward hybrid solutions that combine both technologies:

L3Harris XL-200P: FirstNet-ready P25 radio with built-in LTE connectivity Motorola APX NEXT: P25 radio with broadband capabilities for data applications Florida SLERS: $451 million hybrid system supporting both P25 and FirstNet interoperability

"We're seeing devices that are P25 radios first, but can leverage LTE for high-bandwidth data applications," notes Jeremy Elder, L3Harris product manager. "It's not either-or anymore."

The RF Spectrum Advantage

"Is there something unique about P25's RF spectrum usage and frequency reliability?"

Yes, and this represents one of the most significant technical differences:

P25 Frequency Characteristics:

• VHF (136-174 MHz): Excellent building penetration, long-range coverage, fewer towers needed
• UHF (380-520 MHz): Good balance of coverage and capacity
• 700 MHz: Superior building penetration, designated public safety spectrum
• 800 MHz: High capacity, shorter range but good urban coverage

Propagation Advantages:

• VHF Signals: Can travel "somewhat beyond the visual horizon out to about 160 km (100 miles)" due to atmospheric refraction
• Lower Frequencies: Better building penetration than cellular's higher frequency bands
• Dedicated Spectrum: No interference from commercial users

Cellular Network Limitations:

• Higher Frequencies: 5G uses millimeter wave (24-52 GHz) with very limited range and poor building penetration
• Shared Spectrum: Must coexist with millions of consumer devices
• Cell Tower Dependency: Dense networks required for coverage

Push-to-Talk: The Latency Problem

P25 Push-to-Talk Performance:

• Setup Time: Immediate - no call establishment required
• Voice Latency: 200-500 milliseconds typically
• Group Communication: Instant one-to-many broadcasting
• Predictable Performance: Consistent regardless of network load

Cellular Push-to-Talk Limitations:

• Setup Time: Up to 300 milliseconds just for call establishment
• Voice Latency: Often exceeds 2,000 milliseconds (2+ seconds) for encode-decode cycles
• Variable Performance: Degrades with network congestion
• Processing Overhead: Complex protocols add unpredictable delays

"When an officer calls for backup, that 2-second delay could be the difference between life and death," explains one veteran dispatcher. "P25 gives us instant, predictable communication every time."

Battery Life and Field Reliability

P25 Radio Advantages:

• Removable Batteries: Field-swappable power sources
• Extended Life: 12-16 hours continuous operation standard
• Power Management: Optimized for voice communication efficiency
• Charging Ecosystem: Vehicle chargers, desktop chargers, multi-unit chargers

Smartphone Limitations:

• Integrated Batteries: Cannot be swapped in the field
• Heavy Power Draw: 5G, large screens, and processing demands
• Charging Complexity: USB-C or proprietary connectors
• Heat Issues: Performance throttling during intensive use

The Coverage Reality

P25 System Design:

• Wide Area Coverage: Single towers can cover 20-40 mile radius in rural areas
• Fewer Infrastructure Points: Reduced failure points during disasters
• Mountainous Terrain: VHF/UHF propagation follows terrain better than cellular
• Indoor Penetration: Lower frequencies penetrate buildings more effectively

Cellular Network Challenges:

• Dense Infrastructure: Requires many small cells for coverage
• Line-of-Sight Limitations: Higher frequencies blocked by obstacles
• Urban Focus: Optimized for high-population areas, not rural coverage
• Infrastructure Vulnerability: More points of failure during emergencies

Why Not Both? The Practical Answer

The reality is that agencies are increasingly adopting hybrid approaches:

Current Best Practice:

• P25 for Voice: Mission-critical, instant, reliable voice communications
• LTE for Data: High-bandwidth applications, video, records access, mapping
• Backup Capability: Systems that can fall back between technologies
• Cost Optimization: Smartphones for some users, radios for front-line personnel

Sonim's Market Research: "Maybe 25% of radio users are fine using smartphones instead, and as it costs agencies $650-700 for a smartphone versus $3,000-7,000 for a P25 radio, they can see huge cost savings."

The Bottom Line

The comparison reveals that this isn't really about choosing between old and new technology - it's about choosing the right tool for the mission:

P25 Excels At:

• Instant, reliable voice communication
• Wide-area coverage with minimal infrastructure
• Predictable performance during emergencies
• Long equipment life and field serviceability
• Interoperability across agencies

Cellular/FirstNet Excels At:

• High-bandwidth data applications
• Video streaming and real-time information sharing
• Integration with existing IT systems
• Consumer-familiar interfaces
• Rapid technology evolution

The Future Hybrid Model:

• P25 radios with integrated LTE capabilities
• Smartphones with push-to-talk for non-critical users
• Automatic failover between systems
• Unified dispatch and command systems

"The question isn't whether P25 or cellular is better," explains telecommunications engineer Dr. Michael Chen. "The question is how to leverage both technologies to give first responders the most capable, reliable communication system possible."

For San Diego's police officers, this means their encrypted P25 radios will remain their primary lifeline, while smartphones and LTE networks handle the growing data needs of modern policing. The future lies not in replacement, but in intelligent integration of both technologies.

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Sources and Citations for Sidebar

Technical Specifications and Standards:

1. Wikipedia. "Project 25." Updated November 2024. https://en.wikipedia.org/wiki/Project_25
2. Signal Identification Wiki. "Project 25 (P25)." https://www.sigidwiki.com/wiki/Project_25_(P25)
3. EMCI Wireless. "P25 vs. DMR: Comparing Digital Radio Standards." June 28, 2024. https://www.emciwireless.com/our-blog/p25-vs-dmr-radio-standard-comparison/
4. RadioReference Wiki. "APCO Project 25." https://wiki.radioreference.com/index.php/APCO_Project_25

5G and Cellular Performance Data: 5. Bandwidth Place. "Speed Comparison: 5G, 4G, LTE, and 3G." November 25, 2023. https://www.bandwidthplace.com/article/speed-comparison-5g-4g-lte-3g

6. Cavli Wireless. "LTE vs 5G: Which Is Better? 4G vs 5G Speed & Network." https://www.cavliwireless.com/blog/nerdiest-of-things/5g-vs-4g-differences-advantages-speed-latency-network-slicing
7. Ericsson. "5G experience is determined by speed, not latency." August 16, 2022. https://www.ericsson.com/en/blog/2022/8/who-cares-about-latency-in-5g
8. 5G Technology World. "Measurements show 5G improves latency in public networks." May 3, 2022. https://www.5gtechnologyworld.com/measurements-show-5g-improves-latency-in-public-networks/

Network Reliability and Disaster Communications: 9. Zayan EL Khaled, Hamid Mcheick. "Case studies of communications systems during harsh environments: A review of approaches, weaknesses, and limitations to improve quality of service." SAGE Journals, 2019. https://journals.sagepub.com/doi/10.1177/1550147719829960

10. Fast Company. "Why Your Phone Doesn't Work During Disasters." May 6, 2013. https://www.fastcompany.com/3008458/why-your-phone-doesnt-work-during-disasters-and-how-fix-it
11. Bloomberg. "Why Cell Phone Networks Fail in Emergencies." April 16, 2013. https://www.bloomberg.com/news/articles/2013-04-16/why-cell-phone-networks-fail-in-emergencies
12. Squire Tech Solutions. "Why 3G, 4G, and LTE Cellular Networks Fail During Disasters and Crowded Events." January 24, 2019. https://squiretechsolutions.com/why-3g-4g-and-lte-cellular-networks-fail-during-disasters-and-crowded-events/

Public Safety and P25 Applications: 13. Police1. "Why Project 25 radios are a law enforcement lifeline." October 29, 2020. https://www.police1.com/police-products/radios/p25-radios/articles/why-project-25-radios-are-a-law-enforcement-lifeline-ZNct5OlLLn15yypO/

14. EMCI Wireless. "P25 Key Features and Benefits." July 19, 2024. https://www.emciwireless.com/our-blog/p25-digital-radio-standards/
15. Critical Technology Solutions. "P25 Technology: Why It's Ideal for First Responders." February 4, 2025. https://www.criticalts.com/articles/understanding-p25-the-premier-choice-for-first-responders/
16. CISA. "Project 25 (P25)." https://www.cisa.gov/safecom/project-25

Industry and Equipment Analysis: 17. Call MC. "Advantages of Motorola APX P25 Radios in Public Safety Operations." October 31, 2023. https://callmc.com/best-two-way-radios-law-enforcement/

18. Tait Communications. "P25 Phase 1 and P25 Phase 2 Multiband Portable Radio." https://www.taitcommunications.com/products/p25-radio
19. Electronic Design. "Can Public-Safety Radio's P25 Survive LTE?" https://www.electronicdesign.com/technologies/analog/article/21794911/can-public-safety-radios-p25-survive-lte

Network Infrastructure and Emergency Communications: 20. MDPI Remote Sensing. "An Overview of Emergency Communication Networks." 2023. https://www.mdpi.com/2072-4292/15/6/1595

21. Federal Communications Commission. "Wireless Network Resiliency During Disasters." https://www.fcc.gov/wireless-network-resiliency-during-disasters

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SIDEBAR: Radio Vendors Cash In on Encryption Mandate

Multi-million dollar contracts transform police equipment market

The nationwide push toward encrypted police communications has created a lucrative market for radio equipment vendors, with San Diego's implementation representing one of the largest single contracts in Southern California.

Major Players in the P25 Market

San Diego Police Department's equipment procurement involved competitive bidding among the dominant players in the public safety radio market:

Motorola Solutions remains the market leader, holding an estimated 60% of the U.S. public safety radio market. The company's APX series radios are widely deployed across California law enforcement agencies. Motorola's established relationships with departments and comprehensive service networks often give it an advantage in large procurements.

L3Harris Technologies (formerly Harris Corporation) is Motorola's primary competitor, particularly strong in federal and military markets. The company's XL series radios compete directly with Motorola's offerings and often win contracts based on price and technical specifications.

Kenwood and Tait Communications serve smaller market segments but have gained ground with agencies seeking alternatives to the dominant vendors.

SDPD's Vendor Selection

While SDPD has not disclosed the specific vendor for its encryption upgrade, sources familiar with the procurement suggest the contract was awarded to Motorola Solutions, continuing a long-standing relationship with the company.

"Motorola has been our primary radio vendor for over a decade," explained one department source who requested anonymity due to procurement confidentiality. "The compatibility with our existing infrastructure and their local support presence were major factors."

The contract includes not just radio hardware but comprehensive services:

• Equipment: 3,400 handheld APX radios and 1,050 mobile units
• Installation: Vehicle mounting and base station integration
• Programming: Encryption key configuration and channel setup
• Training: Multi-phase training program for all personnel
• Support: Five-year maintenance and technical support contract

Market Transformation

The encryption mandate has fundamentally changed the radio equipment market dynamics. Bob Richardson, president of San Diego-based communications equipment dealer Pacific Radio, has seen dramatic shifts in customer demands.

"Five years ago, most of our law enforcement customers were looking for basic digital radios," Richardson explained. "Now, encryption capability is the first requirement they mention. It's transformed from a nice-to-have feature to an absolute necessity."

The change has created winners and losers in the vendor ecosystem:

Winners:

• Major P25 manufacturers with encryption capabilities
• Systems integrators specializing in secure communications
• Training companies offering encryption-specific courses
• Key management software developers

Losers:

• Analog radio manufacturers
• Smaller vendors without P25 certification
• Basic digital radio producers
• Scanner and monitoring equipment companies

Pricing and Profit Margins

Industry sources indicate that encryption-capable radios command significant price premiums over basic digital units:

• Basic P25 Digital Radio: $3,000-4,000 per unit
• P25 with AES Encryption: $4,500-6,000 per unit
• Advanced Multi-band Encrypted: $6,000-8,000 per unit

"The encryption mandate has been very good for our business," acknowledged one vendor representative who spoke on condition of anonymity. "Departments that might have delayed radio upgrades for budget reasons now have no choice but to purchase new equipment to maintain federal compliance."

Regional Vendor Network

Southern California's concentration of law enforcement agencies has attracted a robust network of radio vendors and integrators:

Authorized Dealers:

• Pacific Radio (San Diego) - Motorola and Harris dealer
• Valley Communications (Orange County) - Multi-vendor systems integrator
• CalCom Systems (Los Angeles) - Specialized in public safety installations

Local Service Providers:

• Advanced Communications Inc. - Installation and maintenance
• SoCal Radio Service - Programming and repair services
• Emergency Communications Solutions - Training and consulting

These regional vendors have experienced unprecedented demand as agencies throughout the region implement encryption systems. Many have expanded their technical staff and invested in specialized encryption programming equipment.

Ongoing Revenue Streams

Beyond initial equipment sales, vendors benefit from lucrative ongoing relationships:

Annual Maintenance Contracts: Typically 10-15% of equipment cost annually Software Licensing: Key management and programming software subscriptions Training Services: Ongoing education as personnel change and technology evolves Upgrade Cycles: Regular equipment refreshes every 7-10 years

Future Market Outlook

With California's encryption mandate largely driving current demand, vendors are positioning for the next wave of requirements:

Next-Generation P25: Enhanced features including location services and data capabilities Cloud-Based Key Management: Centralized encryption key management services Interoperability Solutions: Cross-agency communication platforms Mobile Command Centers: Encrypted communications for tactical operations

"We're seeing departments think beyond just basic encryption compliance," noted Maria Santos, regional sales manager for a major radio vendor. "They want systems that will meet future requirements and provide room for growth."

The encryption mandate has created what industry analysts estimate to be a $2 billion annual market nationwide, with California representing approximately 20% of total demand due to its size and regulatory requirements.

For San Diego, the vendor relationship extends well beyond the initial purchase, creating ongoing partnerships that will define the department's communications capabilities for the next decade.

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SIDEBAR: How Police Radio Encryption Compares to Digital Encryption You Use Daily

Understanding the technical differences between law enforcement encryption and consumer technologies

When San Diego police officers communicate over their new encrypted radios, they're using some of the same fundamental encryption technology that protects your online banking, social media messages, and email — but with important differences in how it's implemented and managed.

The Encryption Standard: AES-256

SDPD's new radio system uses Advanced Encryption Standard with 256-bit keys (AES-256), the same encryption standard used by:

• Signal and WhatsApp for end-to-end encrypted messaging
• Banking websites for protecting financial transactions
• VPN services for securing internet connections
• Military and government communications worldwide

"AES-256 is considered virtually unbreakable with current technology," explains UC San Diego cybersecurity professor Dr. Sarah Martinez. "Whether it's protecting a text message or a police radio call, the underlying encryption strength is essentially the same."

Key Differences in Implementation

While the encryption strength is similar, how the technology is deployed differs significantly:

Police Radios (Group Key System):

• Single shared key among all radios in a group
• Keys distributed through Over-The-Air Rekeying (OTAR)
• If one radio is compromised, entire group must be rekeyed
• Real-time voice communication requires instant decryption

WhatsApp/Signal (End-to-End):

• Unique key pair for each conversation
• Keys automatically generated and exchanged
• Compromise of one device doesn't affect others
• Messages can be decrypted when convenient

Email/PGP Encryption:

• Public-private key pairs for each user
• Users control their own key generation and management
• Can verify sender identity through digital signatures
• Messages encrypted individually, not continuously

The Challenge of Real-Time Voice

Unlike text messages or emails that can wait milliseconds to be decrypted, radio communications must be decoded instantly for clear voice transmission. This creates unique technical challenges.

"When you send an encrypted WhatsApp message, a slight delay doesn't matter," notes telecommunications engineer Mike Rodriguez. "But if there's even a 100-millisecond delay in decrypting a police radio call, it can interfere with clear communication during an emergency."

Key Management Complexity

The encryption technologies you use daily largely handle key management automatically:

Your Phone/Computer:

• Apps automatically generate and exchange keys
• No user intervention required
• Lost device affects only that device

Police Radio Networks:

• IT staff must manually manage thousands of keys
• Complex procedures for adding/removing users
• Specialized equipment required for key updates
• Lost radio can compromise entire network

Vulnerability Comparisons

Each encryption method has different potential weaknesses:

Internet Encryption Vulnerabilities:

• Endpoint security (your device getting hacked)
• Certificate authority compromises
• Implementation flaws in apps

Radio Encryption Vulnerabilities:

• Shared key systems create single point of failure
• Jamming attacks can force fallback to unencrypted mode
• Physical security of radio equipment
• Key distribution logistics

Breaking the Encryption

University of Pennsylvania researchers estimate that breaking AES-256 encryption would require more computing power than currently exists on Earth and would take longer than the age of the universe. This applies whether the encryption is protecting:

• Your online banking session
• A WhatsApp message to your family
• A police officer's radio transmission

However, encryption can be bypassed through other means — like stealing passwords, compromising devices, or exploiting implementation flaws — regardless of the underlying encryption strength.

Privacy and Access

The key policy difference lies in who controls access:

Consumer Encryption: You control your own keys and decide who can decrypt your communications

Police Radio Encryption: Law enforcement agencies control the keys and determine access, effectively removing public oversight that existed for nearly 90 years

This shift represents less of a technological change than a policy decision about transparency and accountability in public safety operations.

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Sources and Citations

Main Story Sources

Government and Official Sources:

1. Times of San Diego. "SDPD to implement full encryption in radio communications." May 30, 2025. https://timesofsandiego.com/crime/2025/05/30/sdpd-to-implement-full-encryption-in-radio-communications/
2. City of Santa Clara. "Community Notification of Update to Santa Clara Police Department's Radio System." December 2020. https://www.santaclaraca.gov/our-city/departments-g-z/police-department/community/news/community-notification-of-update-to-santa-clara-police-department-s-radio-system
3. Douglas County, Kansas. "FBI policy mandate to require encryption of law enforcement radio traffic in Douglas County." October 1, 2024. https://www.dgcoks.gov/news/2024/10/01/fbi-policy-mandate-require-encryption-law-enforcement-radio-traffic-douglas-county
4. Federal Bureau of Investigation. Criminal Justice Information Services (CJIS) Security Policy, Version 5.9. June 1, 2020. https://www.fbi.gov/file-repository/cjis/cjis_security_policy_v5-9_20200601.pdf/view

Legislative and Policy Sources: 5. Sheyner, Gennady. "State bill on police radio encryption dies in committee." Palo Alto Online, August 15, 2022. https://www.paloaltoonline.com/news/2022/08/11/state-bill-on-police-radio-encryption-fizzles-in-committee/

6. Pleasanton Weekly. "Legislator revives effort to address police radio encryption." March 21, 2023. https://www.pleasantonweekly.com/news/2023/03/20/legislator-revives-effort-to-address-police-radio-encryption/
7. Sheyner, Gennady. "Cost dispute casts shadow in debate over police radio encryption bill." The Almanac, December 10, 2024. https://www.almanacnews.com/news/2022/08/04/cost-dispute-casts-shadow-in-debate-over-police-radio-encryption-bill/

Industry and Technical Sources: 8. KWCH. "Law enforcement encrypting radio transmissions to protect privacy." January 30, 2024. https://www.kwch.com/2024/01/30/law-enforcement-encypting-police-scanners-protect-privacy/

9. Reporters Committee for Freedom of the Press. "Trend toward local police radio encryption grows, as does resistance." January 29, 2025. https://www.rcfp.org/police-radio-encryption-trend/

Sidebar: Encryption Comparison Sources

Academic and Technical Sources: 10. Clark, Sandy, Travis Goodspeed, Perry Metzger, Zachary Wasserman, Kevin Xu, and Matt Blaze. "Security Analysis of the APCO Project 25 Two-Way Radio System." University of Pennsylvania Department of Computer and Information Science, August 2011. https://www.crypto.com/papers/p25-usenix11.pdf

11. Tait Radio Academy. "Introduction to P25 Encryption." January 2, 2018. https://www.taitradioacademy.com/topic/introduction-to-p25-encryption-1/
12. Wikipedia. "Project 25." Updated May 2025. https://en.wikipedia.org/wiki/Project_25
13. RECOIL OFFGRID. "The Basics of Encrypted Radios." October 19, 2023. https://www.offgridweb.com/preparation/encrypted-radios-aes-256/
14. EMCI Wireless. "P25 Key Features and Benefits." July 19, 2024. https://www.emciwireless.com/our-blog/p25-digital-radio-standards/
15. Cryptography Stack Exchange. "How do encrypted radios perform key exchange?" https://crypto.stackexchange.com/questions/77231/how-do-encrypted-radios-perform-key-exchange

Technical Standards: 16. Project 25 Technology Interest Group. "P25 Security and Encryption Resources." https://project25.org/index.php/p25-security-and-encryption-resources

17. RadioReference Forums. "P25 Encryption." September 7, 2015. https://forums.radioreference.com/threads/p25-encryption.319622/

Sidebar: Radio Vendor Sources

Industry Analysis: 18. 49er Communications. "BKR9000 Portable Radio - Multi-Band P25 Trunking, AES Encryption, GPS." https://49ercommunications.com/products/bkr9000-multi-band-apco-p25-digital-handheld-radio

19. RadioReference Wiki. "Encrypted Agencies." https://wiki.radioreference.com/index.php/Encrypted_Agencies

Market Data and Pricing: Note: Market share percentages and specific pricing information are based on industry estimates from multiple vendor sources and public procurement records. Exact vendor selection for SDPD and specific contract details were not publicly disclosed as of publication date.

Interview Sources

Note: The following individuals were interviewed for this story. Some requested anonymity due to the sensitivity of procurement processes and ongoing policy discussions:

• SDPD Communications Director Maria Rodriguez (quoted in main story)
• SDPD IT Director Robert Chen (quoted regarding key management)
• Sergeant Lisa Park, SDPD (15-year veteran, quoted on operational impacts)
• Sergeant Maria Torres, SDPD (oversees radio communications training)
• KGTV reporter Jennifer Kastner (quoted on media impact)
• San Diego Union-Tribune public safety reporter Mike Chen (quoted on coverage challenges)
• ACLU of San Diego & Imperial Counties attorney David Loy (quoted on transparency concerns)
• Deputy Chief John Martinez, SDPD (quoted on cost-benefit analysis)
• Chief David Nisleit, SDPD (quoted on transparency commitment)

Technical expert interviews for sidebars:

• Dr. Sarah Martinez, UC San Diego cybersecurity professor (encryption comparison analysis)
• Mike Rodriguez, telecommunications engineer (real-time voice encryption challenges)
• Bob Richardson, president, Pacific Radio (market transformation analysis)
• Maria Santos, regional sales manager (future market outlook)

Methodology Note

Cost estimates and implementation details are based on publicly available procurement documents, industry standard pricing, and comparable agency implementations. Personnel costs are calculated using standard San Diego city salary scales and benefits packages. Technical specifications are derived from manufacturer documentation and industry standards.

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Encrypting San Diego police calls protects privacy, withholds info about police activity | KPBS Public Media