The Most Secure Phones for Government & Enterprise
A phone that protects against everyday theft or casual snooping is a different product than one built to resist targeted, nation-state-grade surveillance tools like Pegasus and Paragon spyware. The following comparison is built around the second definition, for government agencies, enterprise executives and other realistic targets of sophisticated, well-resourced attackers.
Each secure phone below is evaluated on how its architecture handles the operating systems that spyware is built to exploit: iOS and Android. Some eliminate these operating systems entirely. Others harden them, partition them or add a detection layer on top. Each of these approaches carries very different guarantees. This comparison aims to make those differences clear.
*Sotera Digital Security publishes this comparison based on publicly available information.
Sotera SecurePhone
The Sotera SecurePhone is a secure communications device built by Sotera Digital Security. It runs on Green Hills Software’s Integrity-178B, a real-time operating system built independently of iOS and Android. It’s built for government agencies, enterprise executives, and high-net-worth individuals facing sophisticated, targeted threats.
Stand-out features
- Integrity-178B holds an EAL 6+ certification, the highest security evaluation level of any commercially available mobile operating system. It has been deployed for more than 20 years, including in military aircraft and NASA/DOD systems and has had no known vulnerabilities as of this writing. To achieve its EAL 6+ certification, Integrity 178-B underwent penetration testing directly by the NSA.
- Because it doesn’t run iOS or Android, it falls outside the attack surface that commercial spyware toolkits like Pegasus and Predator are built to exploit. Commercial spyware platforms are typically engineered and operationalized against mainstream mobile operating systems at scale. The SecurePhone is the only phone that runs the Integrity-178B operating system, so there’s no return on investment large enough to justify the effort.
- Independent penetration-testing confirmed that voice and text communications between two SecurePhones could not be intercepted or decrypted using known attack methods; encryption keys are generated and stored exclusively on-device and are never exported. Even Sotera’s own servers have no access to them
- Compartmentalization operates system-wide and intra-app, not just per-application — 96 hardware-level partitions cover every driver and application on the device, enforced at the kernel level, so a failure or compromise in one component can’t spread to the rest of the
phone.
Where it falls short
The SecurePhone doesn’t support installing third-party apps. There’s no app store, no email client, no camera — it’s built and marketed as a secure line for voice and messaging, not a general-purpose smartphone, so anyone who needs those functions will need a separate device.
For organizations where the threat model is nation-state-level mobile spyware, that narrower scope is the whole point: fewer installed applications means fewer paths in.
Bittium Tough Mobile 2C
The Bittium Tough Mobile 2C is a rugged, dual-boot Android device made by Bittium, a Finnish company, marketed for government, defense, and enterprise use.
Stand-out features
- Dual-boot architecture runs two fully separated operating systems on one device: hardened Android 11 for personal use (with Google Play access) and a locked-down Bittium Secure OS for sensitive work, with total data separation between them
- Combined with Bittium’s SafeMove software, the device is approved for NATO RESTRICTED-level communications and nationally accredited for CONFIDENTIAL use in Finland (NCSA-FI, TL III)
- Hardware-based tamper detection and firmware/hardware integrity checks, with MIL-STD-grade resistance to water, dust, and impact
Where it falls short
Independent reviewers have noted the hardware feels dated for the price. And while Bittium markets full separation between the two operating systems, both still depend on a shared bootloader and firmware layer. That’s a different approach than an architecture with no dependency on the Android codebase at all.
Purism Librem 5
The Purism Librem 5 is a phone built around PureOS, a fully free and open-source operating system that isn’t based on Android or iOS, made by Purism, a company focused on digital privacy and software freedom.
Stand-out features
- The cellular modem sits on a physically separate, replaceable card connected via USB rather than integrated into the main chip. This prevents the modem from directly accessing system memory, which can help mitigate against baseband-level attacks
- Three physical hardware kill switches let the user cut power to the modem, Wi-Fi/Bluetooth, and camera/microphone — engaging all three also disables GPS and motion sensors, in what Purism calls “lockdown mode”
- Runs on PureOS, whose full source code is open for independent audit rather than closed proprietary software
Where it falls short
Purism positions the Librem 5 as an open, general-purpose privacy phone for developers and privacy-conscious consumers, not a hardened device built for a nation-state threat model. It carries no independent government or military certification, and ships with a default password that is used for disk encryption, lock screen, and login alike, and is publicly documented on Purism’s own website. It must be manually changed by the user after setup.
Unplugged UP Phone
The Unplugged UP Phone is an Android-based device (built on AOSP, without Google Mobile Services) made by Unplugged, running a customized build called UnpluggedOS with a built-in security layer the company calls the In-App DMZ.
Stand-out features
- In-App DMZ acts as a checkpoint between each app and the outside world. It inspects incoming files for malicious content in the instant between decryption and execution using on-device machine learning trained on exploit signatures, and blocks outbound telemetry before it leaves the app, without breaking the app’s own encryption
- A physical, mechanical battery-disconnect switch cuts power to the device entirely — independently corroborated as a real hardware control, not a software toggle
- Full-disk encryption enabled by default with user-held keys, remote wipe, and a Privacy Center for toggling camera, microphone, location, Bluetooth, and NFC access system-wide
- Retains a full Android app ecosystem and mainstream smartphone hardware (108MP camera, 5G, wireless charging, up to 1TB expandable storage) — normal phone functionality stays intact
Where it falls short
The In-App DMZ is a detection layer added on top of a still-general-purpose Android build, rather than a removal of the underlying attack surface. This is a different kind of guarantee than an architecture with no general-purpose substrate to exploit in the first place. The device also requires an Unplugged account for core functions like messaging and app installation.
IntactPhone
The IntactPhone Opaque is a high-end secure smartphone made by CommuniTake Technologies, an Israeli company, pairing a hardened, custom-built “Android-like” operating system with a centralized enterprise command-and-control platform aimed at governments and security-conscious organizations.
Stand-out features
- IntactOS is built from the source code specifically to strip out the vulnerabilities, . CommuniTake also states it grants customers auditing access to the source code, including drivers and the bootloader
- IntactCC provides centralized, group-based policy control over apps, network access, and device features, similar to an MDM. It also allows remote lock and wipe for lost or stolen devices. Behavior-based anomaly detection across Wi-Fi and cell-tower connectivity is meant to catch rogue base stations and other evasive attacks
- IntactDialog encrypts voice calls via ZRTP with per-call keys discarded immediately after each call, plus AES-256 message encryption, and works across 2G/3G/4G networks
Where it falls short
IntactOS is still an Android derivative rather than a different operating system family entirely, so its security rests on CommuniTake’s own hardening holding up instead of on removing the underlying attack surface. CommuniTake’s specific security claims, including its stated penetration-test results, are self-reported rather than independently published or verified by a named third party.
Glacier Guardian
Glacier Guardian is a secure device platform that pairs altOS, a hardened Android operating system built by CIS Mobile, with Glacier’s own encrypted messaging, calling, and network infrastructure, deployed onto commercial Google Pixel hardware.
Stand-out features
- altOS is developed by CIS Mobile, a subsidiary of CIS Secure Computing that operates an NSA-certified TEMPEST facility
- End-to-end encrypted messaging and calls use OMEMO, an adaptation of the Signal Protocol, with per-message forward secrecy via the Double Ratchet algorithm
- An optional Core VPN layer routes traffic through a rotating, customer-unique obfuscation node using WireGuard, augmented with a post-quantum key-exchange layer intended to resist future quantum-computing attacks on today’s encrypted traffic
- Data at rest on Glacier’s cloud infrastructure is encrypted via AWS Key Management Service, with an option for customers to supply their own managed encryption key
Where it falls short
altOS is still built on the Android Open-Source Project rather than a different operating system family entirely. Similar to Bittium’s and IntactPhone’s approaches, its security depends on how thoroughly the underlying Android codebase was hardened and stripped down, not on eliminating the OS family that commercial spyware toolkits are built to target.
Apple Lockdown Mode and Android Advanced Protection Mode
Apple and Google both offer a single-toggle security mode built directly into their mainstream operating systems, aimed at people who face a high risk of targeted attacks but want to keep using their existing phone rather than switch to a separate device.
Apple Lockdown Mode
- Developed in collaboration with Citizen Lab, a research group that investigates state-sponsored spyware, and introduced in iOS 16 specifically to blunt sophisticated zero-click attacks
- Blocks most message attachment types and link previews, restricts complex web technologies in Safari that have historically been exploited, and blocks incoming FaceTime calls from unknown contacts
- Blocks wired connections to accessories or computers while the device is locked, and prevents installing configuration profiles or enrolling in mobile device management while active
Android Advanced Protection Mode
- Introduced with Android 16 as a single device-level toggle — distinct from Google’s older, account-only Advanced Protection Program — aimed at journalists, activists, and other high-risk individuals
- Blocks app installation from outside the Play Store, disables connections to outdated and less secure 2G networks, and restricts USB data access when the device is locked
- Adds end-to-end encrypted intrusion logging, developed with the Digital Security Lab, so a suspected attack can be forensically analyzed later without the log being accessible to malware already on the device
Where it falls short
Both modes harden a stock consumer operating system rather than replace it with a different architecture — the device is still running the same iOS or Android install most consumers use, with certain features switched off, rather than a purpose-built system with no shared attack surface to begin with. Android’s Advanced Protection Mode is also newer and, as of mid-2026, can’t yet be centrally enforced across a managed device fleet — an organization has no way to require or verify that every employee has it turned on, a real gap for deployment at scale. And unlike a purpose-built device, both are configurations a user has to remember to enable and maintain, rather than a default, architectural guarantee.
