FIX Network achieves significant milestone by the first ever signing of a Bitcoin message over the cellular network

New Capital
FIX Network
Published in
4 min readOct 31, 2019


FIX Network is very pleased to announce that we have completed a giant step towards our goal of securing transactions and private keys on SIM cards. This achievement serves as validation and proof-of-concept of our core technology of storing and managing private keys on SIM cards, and facilitating the completion of public and private signatures over the air.

The FIX Network Security Protocol will ensure the security and safety of private keys that are used by applications running on mobile devices, providing a safe environment for protecting our digital identities and digital assets. A major innovation and a critical component of our solution is the storage of private keys on the subscriber’s SIM card, and the execution of cryptographic operations on that SIM card using cryptographic-enabled applets. Importantly, the private keys are never exposed to the mobile device or to a public network, and this architecture adds a significant layer of security to the storage of digital identities and assets, and for effecting digital transactions.

“The first signing of a Bitcoin message over the air was an exhilarating moment such as when you manage to ride a bicycle for the first time,’’ said Frank Kleinewoerdemann, a cellular security specialist and active contributor to the FIX Network project. “We can now look forward to delivering the open source development tools and a SIM applet that will have a major impact on the cellular industry and the way that end-users will securely interact with the digital world.”

This initial proof-of-concept testing successfully demonstrated the enrolment of private keys employing seed mnemonics and deterministic public key generation, with the signature using secp256k1 and the Elliptic Curve Digital Signature Algorithm (ECDSA). A next generation, FIX-enabled SIM card that natively supports advanced hashing algorithms was hosted in a mobile device to sign the transactions, with a customized Over-the-Air (OTA) gateway providing secure communications to the SIM card using a mobile network.

Below is a screen capture showing the Bitcoin message signature result.
Above is a screen capture showing the Bitcoin message signature result. The same public key was also used in a transaction confirmed here.

Due to the fact that the FIX Network Security Protocol is dependant on the existing cellular infrastructure for providing secure communications and SIM connectivity, the mobile operators are uniquely positioned to take advantage of this solution. These highly regulated operators will use FIX Network technology to provide advanced OTT services such as cryptocurrency wallets, digital identity management, mobile banking and personal data firewalls to their subscribers, providing potentially substantial revenue streams to an industry eagerly seeking new business models. In addition, this solution will be highly effective in preventing fraud, such as SIM swaps, and will enable payment service providers to comply with regulatory directives such as PSD2. Therefore, this important achievement of signing Bitcoin messages on a FIX Network SIM card in conjunction with the cellular network has been met with enthusiasm by our potential mobile operator partners, who are eagerly waiting to present the FIX Network Security Protocol to their global subscriber base.

An integral component of the FIX Network Security Protocol is the “Security Policy”, which is critical for managing the storage, use and recovery of digital assets and identities. Such policies define the rules for governing our digital lives, and are configured by the end-user to suit their specific requirements. Policies will be stored and secured by blockchain technology, and access to these policies will be through mobile devices via the existing cellular infrastructure. In the initial phase of the FIX Network project, the mobile operators will host these policies on a private blockchain within the operator’s own network. However, it is anticipated that with the introduction of improved technology, the FIX Network public blockchain will host all policies and will provide the appropriate security, decentralization and independent community-driven ledger required to support this critical service of trust. FIX Network is proud to have NEM as our blockchain technology partner of choice for this project. However, we are committed to ensuring that the FIX Network solution will be blockchain-agnostic, and plugins will be provided to interface with diverse hashing algorithms. This architecture will facilitate the generic and widespread use of the FIX Network Security Protocol, such as for supporting governmental projects, where proprietary blockchain infrastructure has been implemented.

To encourage community and industry participation, third-party integration and solution standardization, all of the apps provided by FIX Network will be open-source and include APIs (Application Program Interfaces) and SDKs (Software Development Kits). This strategy will promote the rapid development of end-user applications such as crypto wallets, encouraging and accelerating the mass adoption of transformative digital services. In addition, our security policy components will be released as open-source for rapid deployment by mobile operators worldwide.

Read more about SIM Swaps:

Official links:

FIX Network website

FIX Network Community