I. Background

Recently, the news of "the seizure of nearly 130,000 bitcoins (valued at approximately $15 billion) from a Cambodian cybercrime network" has garnered unprecedented attention within and beyond the industry.

U.S. Law Enforcement exploited a pseudo-random number vulnerability in the private key generation process of certain Bitcoin wallets, reverse-engineering private keys through random flaws to track and seize assets.

The root cause of this vulnerability lies in insufficient entropy in the random seed, making private keys susceptible to brute-force reconstruction, severely threatening asset security.

This article analyzes the causes of vulnerability in question, elaborates on the technical security mechanism of BenFen public chain and its ecosystem application BenPay wallet, and provides clear and trustworthy security assurance for our partners and users.

II. A Renewed Warning on Random Number Vulnerabilities

The "pseudorandom number vulnerability" was first identified in 2018, stemming from issues in the Trezor library, affecting certain iOS wallets created between March and July 2018.

Similar issues are also reflected in CVE-2023-39910 (Milky Sad) disclosed in July 2023, involving the implementation of random number generation of the bx seed command in versions 3.0.0 (2017-03-08) to 3.6.0 (2019-08-29) of the open-source tool Libbitcoin Explorer (bx).

The vulnerability arose from using the Mersenne Twister (mt19937) pseudo-random number generator with only a 32-bit system time as the seed, resulting in insufficient entropy.

Attackers can thus reconstruct wallet seeds and derive private keys through brute-force methods, with the core issue of weak-entropy initializations and the use of a non-cryptographically secure pseudo-random number generator.

It is evident that a private key is essentially a long, unpredictable random number, and wallets must rely on high-quality random sources to generate private keys. Ideally, seeds should be derived from system entropy sources or hardware random numbers (e.g., memory noise, device clocks, or user inputs) to ensure randomness and uniqueness.

However, some early implementations used fixed or low-entropy time seeds, resulting in a degradation of randomness and allowing attackers to reproduce the private key generation process through brute force. This is the technical root cause of this incident.

This incident once again serves as a critical reminder to the industry: the quality of random numbers determines the lower bound of key security. As a next-generation open-source blockchain, BenFen employs industry-leading algorithms and processes for random number generation to ensure secure and reliable private key creation. Users can confidently rely on the BenPay wallet and its ecosystem, backed by the technical strength of the BenFen blockchain.

III. BenFen Blockchain Wallet Security Architecture: Multiple Protection with Unified Experience

BenFen public chain natively integrates zkLogin wallet and supports OpenBlock wallet access, achieving a unified account management system in terms of User Experience and security protection.

(A) zkLogin Wallet

BenFen public chain is based on zero-knowledge proof (ZKP) technology, which realizes a secure, efficient, and decrypted account login and transaction verification mechanism. Its native support for zkLogin wallet allows BenPay users to complete identity verification and on-chain operations without directly managing mnemonic words or private keys.

zkLogin Workflow
1. Based on the OAuth2.0 authorization mechanism, users generate a JSON Web Token (JWT) via their OAuth web accounts.
2. The application submits the JWT and salt to a zero-knowledge proof generator to create a transaction proof.
3. Users then leverage this proof to execute transactions on the BenFen blockchain, ensuring secure login and privacy protection.
Proof Circuit Security Design
1. Utilizes the Groth16 algorithm.
2. Employs multi-party computation (MPC) across multiple devices to generate proving keys, mitigating risks of single-point random number leakage or tampering.
3. Security Protection: The random sources are diverse and unpredictable, ensuring that the entire proof generation process is resistant to attacks and verifiable.

BenFen has implemented a secure entrance design of "one-click creation and login wallet" through the zkLogin wallet system, providing BenPay users with a more comprehensive privacy protection mechanism while ensuring a convenient experience.

(B) OpenBlock Wallet

BenFen public chain supports OpenBlock wallet access, providing BenPay users with a verifiable and auditable high-security key management solution. OpenBlock wallet adopts MPC (Multi-Party Secure Computation) and HSM (Hardware Security Module) architecture to ensure the security and unpredictability of private key generation and signing processes.

MPC Multi-Party Computation: Private keys are never exposed in memory, with distributed signing mechanisms eliminating single-point leakage risks.
Random Number Generation: Using the crypto/rand library, the entropy source comes from the system's underlying hardware events to ensure randomness.
HSM Hardware Protection: Signing occurs within a hardware security module, with random seeds derived from chip noise sources, supported by physical-level protection and multi-factor authentication.

BenFen achieves high-level security protection in the key generation, storage, and signature processes of the wallet system through multi-layer encryption and isolation design, significantly reducing the risk of sensitive information leakage for BenPay users and comprehensively ensuring asset security.

IV. Official Commitment

After internal security audits and source code reviews, we solemnly declare:

Neither BenFen nor BenPay series products use Libbitcoin Explorer or any derivative code.
Non-cryptographically secure random algorithms such as mt19937 are not used for key, seed, or mnemonic generation;
And not affected by CVE-2023-39910 or related "Milky Sad" weak random number vulnerabilities.

BenFen and BenPay will continue to follow the National Vulnerability Database (NVD), CVE official notifications, and other latest security information from authoritative security communities, conducting immediate risk assessments and responses in the first instance.

For further technical discussions, we welcome users and partners to contact us via our official secure channel: support@benpay.com.

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