The quantum threat and why post-quantum communication is a must | Read article
+ 44 (20) 8089 0000 |


Why trust KvantPhone with your privacy?

A personal message from Sab Kun
Co-Founder & Executive Chairman of
Arenim Group

Our security philosophy

No matter in which country you live, security and privacy issues are rarely out of the news headlines these days.

As a result, we know that when choosing a security product, most people question why they should trust the software and those who created it. Credibility and trust are at the heart of the KvantPhone service.

This is why we operate with total transparency. We want what we offer to be crystal clear because this is important to our clients who value their personal privacy.

Our mission is to offer a product that gives the best protection in the world at an affordable price, and which is designed with the future in mind. Our team of more than 20 security specialists and telecommunications and software engineers apply their wealth of expertise to the design and implementation of KvantPhone with this objective in mind.

Let me explain our guiding principles in greater detail.

The pillars of KvantPhone’s approach to security:


thorough and
adaptive approach


Ongoing, regular
third-party security

 Your security is at the heart of everything we do.

We know that KvantPhone’s success is entirely based on trust and reputation, which take years to build, but only moments to lose. This is why we have to be systematic and exceptionally thorough.

Over the past fifteen years, we assembled an experienced team of top-level telecommunication and software engineers, IT security experts, and operational managers whose mindset reflects these qualities.
They are a very talented, clever, and dynamic group who also know that especially in our line business, they must constantly adapt to change in order to succeed and excel. We constantly look for ways to test ourselves, and we challenge assumptions about everything.

We have enormous respect for our customers, both large and small. We know you’re entrusting us with the task of protecting your confidential mobile voice communications and safeguarding your private and business secrets. Failure to protect these private conversations could well result in reputational and financial loss, and in some circumstances may even put lives at risk. This is why we are continually improving KvantPhone, fine-tuning its security features while enhancing convenience of use.

All our staff adhere to a strict code of contact:

  • We follow strict internal security policies.
  • We adhere to the latest and most secure software development standards and methods.
  • We only use best-practice cryptography in our systems.
  • Internal security tests and challenges are part of our everyday quality control procedures.
  • We only work with in-house developers on our payroll. Freelance developers working elsewhere may be cheaper, but ensuring the security of such an open network is impossible in practice.
  • We keep up with emerging security-related developments and trends. We constantly update our thinking, seeking to strike a balance between maximal security and ease-of-use.
  • We have an on-going dialogue with external, independent security experts and auditors, quickly implementing their recommendations. We also work with prominent ethical hackers who review our solutions and strengthen our quality control procedures.

Best-Practice Cryptography

KvantPhone only uses best-practice algorithms that are recommended by thought-leaders in IT security. These algorithms are also approved and recommended by government security and military services.

Just as in the space industry, our product must work every time and under any condition. Accordingly, KvantPhone exclusively uses proven encryption and key-exchange algorithms.

KvantPhone also encapsulates post-quantum cryptography adding quantum resilience to our product. KvantPhone is uses “quantum-resistant” mode by default.

In the unlikely case that ours users might find it too early to adopting post-quantum cryptography too early, we can offer a legacy best practice mode as well.

  Quantum resistant mode
Media encryption AES-256 in GCM mode
Authentication One Time Password (RFC 4226)
with SIP Digest
Key exchange X25519 + Kyber Key Encapsulation 1024 signed with Ed25519 + Dilithium5, E2E KEX
Private key protecion Patented, proprietary method for top security
(see White Paper for details)
Man-in-the-Middle protection X25519 + KEM signed with Ed25519 + Dilithium5
Integrity protection Signed Voice/IM packets
SRTP authentication AES-GCM AED
RTP authentication Secure RTCP
Replay attack protection Ratcheting mechanism
Backup/restore protection Password authenticated key agreement (OPAQUE)

Ongoing regular third-party security assessments

KvantPhone – and its previous product CryptTalk developed in 2009 – is constantly reviewed and benchmarked by third-party reviewers. We analyze their feedback as part of our quality assurance program and use their recommendations to make improvements to the system. If our non-disclosure agreement allows it, we make third-party reviewers’ findings public. The following list summarises the disclosable reviews/audits. We regularly update this list as new reports become available. Copies of the full (disclosable) reports are available from Arenim upon request.


Third-party security review track record –
Arenim’s secure communication product line

Date App version Review done by Description
2012 June CryptTalk 1.4 YS Re-assessment of the new registration process of the app’s iTunes version.
Review of the user management and admin interface.
2013 April – 2013 October CryptTalk 1.8 Gergely Trifonov – independent auditor Application and system plan review
2013 November CryptTalk 2.0 One of the “Big Four” firms CryptTalk 2.0 Client and server system plan review
2013 December – 2014 May CryptTalk 2.0 Gergely Trifonov – independent auditor Continuous code and application review
2014 May CryptTalk  2.0 Silent Signal Mobile application security assessment
2014 June – 2014 August CryptTalk  2.4 Gergely Trifonov – independent auditor CryptTalk 2.4, 2.5 development support – continuous review
2014 September CryptTalk 2.4 Gergely Trifonov – independent auditor Mobile application security assessment
2015 January CryptTalk 2.5 Gergely Trifonov – independent auditor CryptTalk 2.5 Client and server system plan review
2015 May – 2015 June CryptTalk 2.5.0 NCC Group, UK Complex mobile application security assessment
2015 September CryptTalk 2.5.3 Silent Signal Re-assessment including new CT standard version’s registration process and internal admin interface
2015 November CryptTalk 2.7.2 Silent Signal CryptTalk iOS 2.7.2
2017 February CryptTalk 2.9.5 NCC Group, UK CryptTalk iOS 2.9.5
2018 February CryptTalk 3.4.0 Silent Signal AUMI 3.4.0
2018 March CryptTalk 3.1.2 Silent Signal CryptTalk Android 3.1.2
2019 November KvantMail 1.0.2 Silent Signal KvantMail security assesment for a white labeled product (iOS, Android, Webmail and Admin Interface)
2021 December CryptTalk 4.4 Silent Signal Group Messaging, File Transfer, Licensing and Admin interface
2024 May KvantPhone 2.0 Silent Signal Post-Quantum cryptography, Product migration, Admin interface


If you would like to know more details about secure communication and
KvantPhone’s security, please see the following articles and resources:


KvantPhone Security
White Paper

Discover how KvantPhone makes your
communication completely secure.

Read White Paper


Why to secure

Learn more about why to use secure communication tools.

Read our article


The quantum

Understand in detail the quantum threat and why Post-Quantum Communication is a must.

Read our article

Are you looking for using KvantPhone
for personal or business purposes?

Personal use

Encrypt your personl digital online communication with KvantPhone’s end-to-end, quantum resistant encryption.

Business use

Increase business productivity with complete business communications privacy and security.