Before reading:
Please note that we do not sell any devices, this is not a web store. We are not related to XCell Technologies, nor a subsidiary. If you want to buy any Stealth Phones, please contact manufacturer.

XCell Technologies has launched on 1st January 2019 their new flagship product: XStealth, an epic Android based Stealth Phone. Announced as a game changer, XStealth is one of a kind Stealth Phone. No other "secure" mobile phones have the same special functions and capabilities as XStealth have. Now, you can stop hiding. Be invisible and fight back with XStealth Phone.

Mobile technology has never played a more important role in personal security and basic rights than it does right now. XCell Technologies is uniquely poised to address the dangers of mobile interception used illegally or abusively by state towards its citizens, following shortsighted policies.

The next big thing is here. There was no perfect Stealth Phone, until now. The upcoming generation of Super Stealth Phones has been successfully rolled out.

There's been a lot of talk about Android Stealth Phone since 2014, when XCell Technologies released their first Android Stealth Phone, under Law Enforcement Product Line. Took them 4 years to develop the most advanced, the most secure Stealth Phone they have ever built. Excessively tested on all major interception systems, intensively used by field operatives and confirmed by their main clients as the most suitable for covert actions, when being a step ahead your enemies can be the difference between failure and success.
Based on XStealth military version released back in 2014 and stuffed with new and unprecedentely special functions, XStealth is now available for public use.

What do you want from a Super Stealth Phone? Everything, probably. After all, it's about your security. Well, with new rolled out XStealth Phone, you've got everything. And the best is yet to come.

Android Super Stealth Phone comes now in two flavors. Since XStealth Lite has been built for personal use, XStealth devices are aiming professionals ranging from govt to law enforcement and homeland security agencies. XStealth Pro is also coming as top notch product.

You can read more abour XStealth special functions, below. We hope that will get out hands on new device soon, for testings and first impressions.

While the rest of the market is going one way, with text and voice encryption, XCell Technologies is going down another, to the heart of problems, sticking with privacy and security based on interception detection and fighting against interception by using quite the same network weaknesses that IMSI Catchers and GSM Interceptors use. XStealth Phones are actually the only ones that can effectively fight back mobile interception, by using both defensive and offensive security methods.

Get the most out of your Super Stealth Phone, with our breakdown of specs:

First, about XStealth hardware security.

There is a kill switch to self-destruct on command even if the phone is turned off. As no other secure phones, XStealth USB port is protected by our well known volatile security filters: any attempt to connect the device to any other external device (no matter if PC, service box or forensic grade equipment), other than its own paired charger, will trigger a self-nuke mechanism that literally fry the whole motherboard in the same way as USB Kill work.
Anti-tamper JTAG protection is also implemented: serial communications interface for low-overhead access without requiring direct external access to the system address and data buses are disabled by default at  serial interface level.

XStealth Phones use a Tamper-Resistant Platform: any unauthorized attempts to connect the phone to any external device will delete the keys that encrypt all sensitive data. A remote wipe function is also available.
Authentication to login to the phone uses multi-factor (MFA) technology, voice biometrics being one of them. Due to security risks involved by face and fingerprint recognition login, these options has been removed.

Trusted Execution Environment (TEE) uses encrypted memory and includes a hardware random number generator. Communication between the Secure Environment and the application processor is isolated to an interrupt-driven mailbox and shared memory data buffers.

There is also installed a Data Execution Prevention (DEP) technology to mitigate memory-based attacks. This defensive technology dramatically narrows the attack surface area for memory related exploits by preventing code from being executable in sections of memory that have specifically allocated for read only data. DEP support is a critically important defense when used in conjunction with Address Space Layout Randomization (ASLR). These core improvements make it more difficult for spyware to perform buffer overflow, heap spraying, and other low-level attacks. Therefore, even if an attacker succeeds in loading the spyware code into memory, the spyware code will not execute.

XStealth Phones are not susceptible to side channel attacks, including various forms of power analysis attacks to ensure the protection of cryptographic keys.

XStealth Phones has the ability to execute a secure boot based on using a hardware root of trust for checking and storing hashes or signatures of firmware and other software loaded starting with the initial BIOS.

XStealth Phones have separates CPU from Cellular Baseband, preventing this way external manipulation by baseband attacks.

Now about XStealth software security.

Today too many apps are engineered to collect and disseminate enormous amounts of user data—such as location, Web browsing histories, device-unique IDs, search terms, and contact lists – data they often simply don’t need. Some app providers also try to obfuscate their data collection functions to get around restrictions by marketplaces such as Apple’s that are intended to prevent abuse of APIs and ensure better privacy for users. For example, researchers have recently discovered hundreds of apps in the App Store that extract personally identifiable user information via private APIs that Apple has forbidden them from calling. The abuser that was singled out – a Chinese mobile advertising developer called Youmi – used simple obfuscation techniques and dynamic linking to get around the application vetting checks performed by Apple. Same for Android platform, on weaker Google Play Store.

XStealth Phones runs a special version of the Android operating system—XROM—that blocks many of the ways phones leak data about your activities. XROM is an Android fork developed by XCell Technologies; it uses Google’s code for the underlying platform, but skips Google Services in the same way Amazon’s FireOS does.
The connection between XROM and software applications is filtered by Secure X-OS bridge, keeping both firmware and software applications away from exploits. Obfuscated code is adding an extra protection layer.

XStealth Phones does have Android trackers disabled by default, leaving no traces on Internet.

XStealth Phones comes with preinstalled generic applications which we have modified certain features (like removing back doors used by law enforcement and some security flaws), adding a plus of security and privacy (especially for Yahoo and Hotmail clients). This is why we have blocked any OTA software update which can restore security issues. Software updates usually refer to compatibility with new Android versions, which is not  our case and will not impact application workflow.

Regarding anti-virus application and software updates:

XROM firmware is secure by default: no other software applications can be installed by the phone user (which have the phone on its hands) nor remotely, by obscure third parties or abusive law enforcement. Hence, no anti-virus software is needed. Also, XStealth Phone will not perform any OTA firmware/software update, which may lead to remote exploits. You have to understand our point of view and hopefully reconsider your approach when it comes to mobile security: XStealth Phones are not aiming average users. All our Stealth Phones has been developed for professional use: intelligence agencies, law enforcement and homeland security. All above entities does not relay on encryption when it comes to secure communications because of a simple fact: all mentioned agencies have legal access and gain information they need by using back doors provided right by the software developers. If there is no cooperation from developer, then they will use another effective methods to gain access to relevant info, other than the ones used by hackers. There are plenty of companies that provide a wide variety of methods to penetrate any system such as computers and mobile phones. FinFisher is one of them: "Our Deployment Methods & Exploitation Solutions cover the latest PCs, smartphones, tablets and most common operating systems." "FinFisher can be covertly installed on targets' phones by exploiting security lapses in the update procedures of non-suspect software." "The software suite, which the company calls "Remote Monitoring and Deployment Solutions", has the ability to take control of target phones and to capture even encrypted data and communications. Using "enhanced remote deployment methods" it can install software on target phones." FinFisher malware is installed in various ways, including fake software updates and security flaws in popular software. Sometimes the surveillance suite is installed after the target accepts installation of a fake update to commonly used software. The software, which is designed to evade detection by antivirus software, has versions which work on mobile phones of all major brands.

FinSpy is a field-proven Remote Monitoring Solution that enables Governments to face the current challenges of monitoring Mobile and Security-Aware Targets that regularly change  location,  use encrypted and anonymous communication channels and reside in foreign countries. FinSpy is bypassing 40 regularly tested Antivirus Systems. Hence, no point to install an anti-virus as you have mentioned. XCell Technologies have opted for another effective solution to circumvent malware and harmful software install.

Please see also this short movie regarding remote mobile surveillance by "updating" a BlackBerry cell phone application: https://www.youtube.com/watch?v=n5ZJUXweayo

Even worst, also a not so skilled hacker can easily remotely install a spy application on a mobile phone which will not be detected by any antivirus, by the same "software update" procedure: https://www.youtube.com/watch?v=LicdrZwmHQo

There is a FinSpy detection algorithm installed deep on XROM firmware that will not only detect any intrusion attempt, but will block any code execution.

Encrypted bootloaders comes as standard option.

XStealth Phones are also using SIM Toolkit inhibitor, a blocker for remote code execution via SIM Toolkit (used usually by both network operator and law enforcement).

XStealth Phones use adaptive security defenses, being ultra-secure and adaptive [personal] smartphones: we will install before shipping any software application desired by the buyer, but only after running a comprehensive security audit. We will refuse to pre-install applications that can affect user privacy and security, and phone functions. No file explorers will be installed, as well as forensic clients or modded applications.

There are also things that we will not make them public available, as encryption algorithms used and firmware source code, simply because for any cryptanalyst will be more easy to break encryption when used encryption algorithms are known.
Also, a user controlled source code is not an option for XStealth Phones: that might be a huge opportunity for hackers and state controlled entities to find exploits, remote install/RAT or spyware which in the end of the day will lead to no security.

Please see below a list of special functions and default software applications.
Special functions command panel is password protected, accessible only by dialing a secret code.

1. Calibrate. First time when you activate the phone, you should run Calibrate function: the phone will self-calibrate, testing GSM network and saving data regarding home network, which is a part of auto-learning process. It is essential to use a new SIM card (no matter if contract or prepay) and to be in a safe place (connected to a real GSM network).

2. IMEI Change function. The user can control the way IMEI is changed (after every event as phone call or SMS, on network/IMSI Catcher request, etc.), and also can define its own IMEI, performing this way different protection scenarios. More info on User Manual.

3. IMSI Change function. Once enabled, the phone will start SIM cloning, generating valid IMSIs which are used for the next calls and messages. There are no other cell phones that can perform IMSI change. Please note that no Internet connection, third party servers or special SIMs are needed. Also, no monthly fees or other strings attached. Will work virtually with any SIM card, but we recommend using MNO SIM cards.
NOTE: This function is not available for XStealth Lite

4. Mode: the user can switch between Hunting Mode (call/SMS interception detection) and Anti Interception Mode (no calls and messages can be sent or received as long as phone interception is active, no matter if GSM Interceptor or SS7 means are used).

5. A5 Alert. Once enabled all, phone user will be warned in real time if voice and data connections are intercepted.

6. Location Tracking Alert. Once enabled, the phone will warn if a location tracking ping is received.
Ki extraction alert: every time when a GSM Interceptor is trying to get Ki (encryption key stored on SIM card) by sending so called "challenges" waiting for SIM replies with parts of encryption key, for later Ki calculation.

7. Real GSM Location Spoofing. The phone user can choose which cell tower the phone is connected to. This way, any triangulation technique used for location tracking purposes will generate wrong results which leads to false location. For easy of use, Optimal location spoofing should be enabled: the phone will always connect to the farthest cell tower, no matter if stationary or on the move

8. Channel Lock. The user can lock ARFCN (uplink and downlink - the radio channels pair that cell tower communicate with the cell phone and vice versa) in order to block any forced handover (forcing mobile phone to quietly disconnect from home network and connect to a fake cell tower impersonated by a GSM Interceptor

9. C2 Monitoring. The phone will monitor C2 parameter (cell re-selection criterion), which is used by IMSI Catchers/GSM Interceptors in order to force cell phone connection. Will also look for neighbor cell towers identity. In case the phone is connected to a GSM Interceptor, no cell towers will be shown as neighbor towers.

11. Sandbox. A separate secure partition where IMEI engine, IMSI engine and other security related software components run smoothly, out of any interference and tampering possibilities. The user can check at any time the integrity of Sandbox and its components.

12. Network Scan. A live network monitoring tool, looking for IMSI Catchers/GSM Interceptors, SS7 based interception and other network anomalies. A real time interception detection function is also available. No false positives due to intelligent scanning mode.

NOTE: This function is not available for XStealth Lite.

13. LAC Change Detector. This is the Proximity Alert Function. The phone will detect any abnormal LAC (Location Area Code) when stationary, changes made only by IMSI Catchers/GSM Interceptors in order to force connection

All data regarding mobile network - including LAC changes - is saved in a text document.

14. Microphone Lock. User can lock the microphone at any time, preventing remote activation and listen in on the environment.

15. Camera Lock. User can lock the camera at any time, preventing remote activation for spy pictures/movies

16. On Screen Functions

For easy of use, main monitoring and warning functions are displayed also on the home screen. Since main home screen looks anonymous and like any other smartphone, by a simple screen swipe all monitoring functions will pop up on the screen.

Call workflow
Every time when user is making a call, the phone will check for standard GSM network encryption (A5/1) detecting if the call is intercepted off air (by a GSM Interceptor) or at network switch level (SS7), by pinging the network core. In case of call interception, the phone will display a visual alert.

There are also default applications installed on the phone:
 - Proton Mail
 - Proton VPN
 - Tutanota client
 - Telegram X
 - Hotmail client
 - Yahoo client
 - Microsoft Outlook client
 - PayPal client
 - Facebook lite client
 - Messenger client
 - Fire Onion
 - Orbot
 - Tor
 - Orfox
 - Anti-theft security & alarm
 - Security Lock
 - Secret Photo Video Locker
 - Open Signal -  a comprehensive cell tower locator
 - Burner: temporary disposable phone numbers

If you are either super important, super paranoid or a super spy, there are times when you need to be able to use a cell phone and not leave a trace or any chance to anyone to intercept your calls and text messages, including law enforcement and intelligence agencies.
 
Secure = encryption? Well, think again...
 
Nowadays, interception issue affects most of the people, even if they are not aware of it. Not to mention so called “off air GSM interception systems” or also known as “IMSI-catchers”, "GSM Interceptors" or "StingRays", it has been known since 2014 that using the legacy SS7 (Signaling System No. 7) protocol SMS based traffic text messages can be easily intercepted by using diameter based networks independently of device or OS type. Signaling System No. 7 vulnerabilities are easy to be exploited even by hackers, being a 50-year old protocol that is probably part of a majority of cell phones and text messages in the world.
Generally speaking, most of aware users regarding cell phone interception by above technologies, believe that using encryption solutions will secure their calls and text messages. It is encryption a real solution? Let's see...

Law enforcement, homeland security and other related actors have plenty of methods to intercept messages and read text content, even when using encryption. Ranging from SS7 exploit, encryption backdoors or intentionally weaken popular encryption algorithms to lawful hacking that circumvent encryption and hitech decryption technology, all are there at their fingertips.
 
Encryption will not protect your privacy. At all
 
Recent headlines warn that the government now has greater authority to hack your coell phones, in and outside the US. Changes to federal criminal court procedures known as Rule 41 are to blame; they vastly expand how and whom the FBI can legally hack cell phones. But just like the NSA's hacking operations, FBI hacking isn't new. In fact, the bureau has a long history of surreptitiously hacking us, going back two decades.
 
Back-doors provided for law enforcement
 
Encryption back doors remain largely viewed as weakening everyone’s protections all the time for the sake of some people’s protections on rare occasions. As a result, workarounds like the FBI found are likely to be the most common approach going forward. Indeed, in recent years, law enforcement agencies have greatly expanded their hacking capabilities.
Many reputable encryption developers and companies have chosen to retain the ability to read and use their customers’ content, or perhaps they decided there is not a sufficient business case to add end-to-end encryption or user-controlled encryption. Their users’ encrypted content is more readily available to law enforcement because they hold the decryption keys. The same companies offer their services in a way that encryption does not preclude their ability to hand over the content to law enforcement in response to a warrant. Are those services as secure?
 
Lawful hacking
 
Most of national security agencies had been shown to have immense surveillance capabilities actively deployed on a mass scale, especially in those countries where the functions of law enforcement and national security overlapped. Beside encryption master-key and built-in back doors that provide law enforcement exceptional access to anyone secrets and privacy, they now have unprecedented access to information through open-source intelligence, collection of metadata, sophisticated traffic analysis tools and data analysis algorithms. Many local and international laws are mandating insecurity by requiring government access to all data and communications that permits lawful hacking (otherwise known as encryption circumvention).
 
Encryption vendors and law enforcement work together to solve access "problem". One suggested fix is one way information sharing where vendors make law enforcement aware of unpatched exploits, allowing the government (and anyone else who discovers it) to use these vulnerabilities to gain access to communications and data. It's a horrible suggestion - one that puts vendors in the liability line of fire and encourages continued weakening of device and software security.  
Several individuals with backgrounds in security and systems have begun to explore possible technical mechanisms to provide government exceptional access.

XCell Technologies is really serious about mobile security, bringing you the most advanced SMS security solutions. Concerns about government mass surveillance and their ability to decrypt anything by using given master-keys, backdoors, lawful hacking or effective decryption solutions were the factors driving us to develop a brand new and 100% secure SMS communications which use not only strong military grade encryption but adding a new security layer by exploiting GSM network via MLSP®, to make sure there is no way to intercept text messages or metadata, even in encrypted mode. All above overleap existing commercial-encrypted apps, services, devices, and also law enforcement access to your sensitive info.
GSM provides by default only a basic range of security features to ensure adequate protection for both the operator and customer. Over the lifetime of a system threat and technology change, and so the security is periodically reviewed and changed here on XCell Technologies, and then applied on our products.
Taking advantage on GSM network architecture and SMS Transport Protocol, our SMS encryption technology is capable to send/receive encrypted and non-interceptable messages.
Our SMS encryption application called XCrypt use a groundbreaking multi-layer technology to protect SMS from being intercepted and decrypted. As a unique encryption application, beside strong military grade encryption, XCrypt use a brand new patented technology in order to send/receive encrypted messages: discrete GSM channels or Multi-Layer Security Protocol®. That will protect not just encrypted text messages but also metadata which is not encrypted.

Definitions

• "A-Party" phone is the sender phone which send encrypted messages via MLSP®
• "B-Party" phone is the receiver phone that will decrypt and display received message.
• Plain text message: a standard text message that can be read by anyone. Can be intercepted and read with no effort.
• Encrypted message: an encrypted text message that can be read only by using the right password. Can be easily intercepted in encrypted mode but cannot be read. A password is required in order to read the message.
• Metadata: data about data. SMS metadata is not encrypted because is not contained by the encrypted text itself, but law enforcement agencies are collecting unencrypted metadata to characterize the encrypted data. SMS metadata contain data about sender, receiver, message encoding (UTF8, UnicodeX etc.), date/time and length.
• Non-interceptable message: a text message (plain text or encrypted) which cannot be intercepted by any means.
• Real end-to-end encryption: no Internet and 3rd party servers involved.
• XCrypt: software application that use MLSP® in order to send/receive ultra-secure messages.

 
MLSP®
 
Multi-Layer Security Protocol - MLSP® consist in:
1. Physical layer: encrypted text message.
The phone will encrypt text messages by using following protocols:
• RSA
• AES 256
• Elliptic Curve (ECIES) 256
• SHA256
• Protected by ITSEC Evaluation level 3
2. Multi-layer routing and transport protocol. Encrypted SMS data is randomly segmented and distributed in bursts by Application Port Addressing Technology, via discrete GSM channels which usually are not "listened" by mobile interception systems (IMSI Catchers, GSM Interceptors or StingRays), both in air interface (UM Interface in terms of GSM networks) and Abis, A and C-G mobile network interfaces. This way, SMS data which is usually sent over GSM Layer 1 (and widely intercepted on Layer 1) will be sent by using a combination of GSM Layer 1 and GSM Layer 2 (LAPDm). By consequence, no mobile interception systems (as GSM Interceptors) and lawful interception systems (SS7 interception also known as network switch based interception or interception by the help of network operator) will be able to intercept the whole message but only a few bursts which are encrypted anyway.
3. Metadata protection. Regular SMS metadata is not saved in a separate file (called a metadata file). XCrypt separate metadata and the data it describes (SMS encrypted text), sending metadata file in bursts over the network, by the same Port Addressing technology. Metadata is of little value without the data file (SMS) it relates too. At the same time, metadata makes the data more usable and therefore, more valuable. An encrypted text message with separate metadata file will reveal nothing about SMS sender and receiver.

1. Phone level
 
At phone level XCrypt use a technology called port directed SMS, which is widely implemented in J2ME MIDP on mobile devices. The concept is basically that when an user send an encrypted SMS message to "B-Party" phone, a particular port number will be specified along with encrypted message, so only the device which is "listening" on that particular port will be able to receive an encrypted message. When a message is received on a port that the application is listening on, the message gets directly routed to secure Inbox instead of going to the standard message Inbox.
XCrypt will locally encrypt text messages at military level, then by message segmentation and Port Addressing will send randomly splitted bursts (bit streams) along with certain port address data by adding redundant bits to information binary string, to "B-Party" phone. Along with encrypted split message, the application on "A-Party" phone will send Port Addressing data, which will trigger opening certain Port Address on "B-Party" phone. This way, encrypted message will go through, avoiding standard phone Inbox and arriving directly on secure Inbox.
All this steps are transparent on receiving ("B-Party") phone, which also require user interaction which have to allow message to be routed to secure Inbox and decrypted by inserting the right password.
On "B-Party" phone, by port destination address, encrypted bursts will be selectively received, concatenated, decrypted and displayed only on "B-Party" phone which use the same XCrypt application that "listen" on certain receiving ports.
If on the "B-Party" (destination phone) is not also installed XCrypt app, then received message will not be delivered nor displayed by the phone (not even in encrypted/unreadable mode) due to Port Addressing technology which filter messages by port address.
When encrypting SMS, metadata file will be generated separately from text message and not as an integral part of the message as regular SMS do. Metadata file will be then truncated and sent in bursts over GSM network, by Port Addressing technology. This way no metadata can be intercepted by SS7 means.
At this level, handset vulnerability refer to forensic grade hardware and software that intend to extract system files and private data off the phone, including decrypted messages stored on XCrypt secure Inbox. XCell phones are protected against forensic procedures by USB volatile filters which does not permit any unauthorised USB connection, triggering motherboard self-nuke. Moreover, XCrypt run on Sandbox partition which is 100% encrypted and protected against file extraction by self-delete mechanism.
 
2. Um level
 
Um interface (the radio link between the cellular network and the subscriber handset) is the most vulnerable and exploited part of the GSM network by MItM attacks (IMSI Catchers, GSM Interceptors and StingRays), since no network operator help or target consent is needed. XCrypt will make use of GSM network architecture and SMS Transport Protocol in order to protect (already) encrypted messages to be intercepted even in encrypted mode. After encryption, the modulation signal has a carrier wave using GMSK (Gaussian Minimum Shift Keying) modulation. GMSK is a two-state modulation based on the frequency keying stroke.  
On Um interface XCrypt will use MLSP® technology: encrypted message bursts are not sent only on usual L1 SMS channels - SDCCH (Standalone Dedicated Control CHannel) signaling channels, but also on other available channels which are not subject of SMS interception, forcing Signaling Layer 2 (data link layer based on LAPDm protocol) for SMS Transport.
Since GSM Interceptors are "listening" only SDCCH physical channels in order to intercept text messages, will catch only a few encrypted bursts sent over SDCCH but not the whole encrypted message which is split and sent over multi-channel by MLSP® technology.
Same for metadata file: is sent over the network in bursts, separately from encrypted message body. No metadata extraction is possible at this level.
 
3. Core network level
 
The four-layer transport protocol stack of SMS (application, transfer, relay, and link) is used at this level and the transfer layer of this stack is the one which secure text message. GSM core network consist in Mobile switching center (MSC), Home location register (HLR), Authentication center (AuC), Visitor location register (VLR) and Equipment identity register (EIR), which are all vulnerable to network switch based interception, also known as SS7 interception or lawful interception. This kind of interception can be successfully performed only by law enforcement and homeland security agencies, by the help of network provider that allow monitoring hardware installation (SS7 boxes) at their core network based on Communications Assistance for Law Enforcement Act (CALEA). CALEA's purpose is to enhance the ability of law enforcement agencies to conduct lawful interception of communication by requiring that telecommunications carriers and manufacturers of telecommunications equipment modify and design their equipment, facilities, and services to ensure that they have built-in capabilities for targeted surveillance, allowing federal agencies to selectively wiretap any telephone traffic. CALEA covers mass surveillance of communications rather than just tapping specific lines and not all CALEA-based access requires a warrant. Generally, lawful Interception implementation is similar to the implementation of conference call. While A and B are talking with each other, C can join the call and listen silently.
 
At this network level, the main security vulnerability consist in lawful interception. XCrypt is taking advantage on GSM core network, sending both encrypted and non-interceptable text messages by using MLSP® technology. Core network protocols cannot be enforced as Um interface can. Actually there is no need to manipulate those protocols and transfer layers as long as message bursts that transit this part of the mobile network can be logically concatenated (fit together) by Port Addressing and decrypted only by "BParty" phone which run the same XCrypt application and by knowing the right password. By consequence, no text messages can be entirely intercepted by a third party that use CALEA - lawful interception. A few encrypted SMS bursts which are eventually intercepted by SS7 cannot lead by any means to SMS interception. Thus no private data will be collected by this method, phone user privacy being preserved peer-to-peer from "A-Party" to "B-Party" phone.
Let's face it: most of nowadays encryption solutions are taking care only on text itself, neglecting message metadata which are still sent on plain text over the network, due to network requirements. Law enforcement and other actors are taking advantage on this, collecting unencrypted metadata to characterize the encrypted data, metadata being this way a valuable source of information for them.
By using MLSP® technology on both Um and Core network levels, collecting unencrypted message metadata is not possible, thus no way to extract any additional info beside encrypted message.
It has long been said that it doesn’t matter how secure your organization, or personal information and assets, are if you connect them with third parties that are less secure. So take note: servers are third parties.
A real end-to-end encryption require no third parties involved on the way from "A-Party" to "B-Party" phone.
 
For maximum level of security and privacy, XCrypt does not require any Internet connection, third party servers or monthly subscriptions. All processes and protocols run locally on the phones (on Sandbox partition) providing this way not just a real end-to-end unbreakable encryption, but also non-interceptable messages by the reasons explained above.
XCrypt has been already implemented as standard on XCell Basic v3 Stealth Phones, both on Basic and Advanced versions.