BitCoreFinder

BitCoreFinder: A Cryptanalytic Tool for Recovering Lost Bitcoin Wallets by Exploiting Vulnerabilities in the NaCl Library

Modern cryptocurrency wallets, particularly for Bitcoin, rely on cryptographic protocols that demand high resilience and reliability in key generators and encryption algorithms. However, the widely used NaCl (Networking and Cryptography Library) has revealed a number of vulnerabilities and implementation flaws over years of use, opening new avenues for cryptanalysis. This article examines BitCoreFinder — a specialized software tool that exploits the cryptographic weaknesses of NaCl and related algorithms to recover private keys and seeds used in Bitcoin wallets. BitCoreFinder’s methodology is based on a critical analysis of key generation and handling flaws in the Salsa20, Curve25519, Poly1305, SHA-512 algorithms, and ECDSA/DSA digital signatures, while applying modern computational technologies to enhance recovery efficiency.

With the growing popularity of cryptocurrencies, there is an increasing need for secure storage of cryptographic keys to safeguard users’ funds. In most cases, Bitcoin wallets utilize BIP39 standards and key generation via algorithms implemented on top of the NaCl library. Despite its widespread use, NaCl initially contained several shortcomings that drew the attention of cryptanalysts.

BitCoreFinder is a tool implementing a comprehensive approach to analyzing known vulnerabilities within this library, enabling the recovery of lost or corrupted Bitcoin wallets. Unlike traditional methods relying solely on seed phrase or wallet.dat file recovery, BitCoreFinder employs deep technical analysis and cryptanalysis of implementation vulnerabilities.

Theoretical Foundation and NaCl Vulnerabilities

NaCl, as a cryptographic framework, implements critical security algorithms, including:

Salsa20 — a stream cipher where reuse of a one-time key (nonce) compromises key information;
Curve25519 — a widely used elliptic curve for private key generation with shortcomings in random number (entropy) generation, facilitating error recovery;
Poly1305 — a message authentication algorithm vulnerable to information leakage due to buffer overflows;
SHA-512 — a cryptographic hash function susceptible to specially crafted input attacks causing crashes and hangs;
ECDSA and DSA — digital signature algorithms with flexibility allowing signature modification without invalidation, enabling mathematical analysis and private key extraction.

The security of cryptographic systems directly depends on the quality of random number and key generation. Vulnerabilities in the entropy generators used in NaCl, as well as protocol implementation errors, greatly increase the risk of losing control over wallets.

BitCoreFinder Methodology

BitCoreFinder exploits these vulnerabilities through:

Analyzing and detecting nonce reuse in Salsa20 allowing recovery of key material through cryptanalytic attacks on cipher streams;
Cryptanalysis of Curve25519 key generation weakness by analyzing correlations and patterns in encrypted data for key recovery;
Identifying Poly1305 implementation errors causing buffer overflows and data leakage;
Exploiting SHA-512 vulnerabilities at the data processing level to detect crashes and predictable internal states;
Applying mathematical analysis of ECDSA signature malleability to alter transaction signatures without invalidation, revealing parts of the private key;
Processing weak or partial seed phrases and passwords using CPU/GPU multithreading to exponentially increase successful recovery chances;
Automating and integrating classical cryptanalytic techniques with modern computational methods to accelerate recovery and improve accuracy.

Architecture and Computational Capabilities

For effective search, BitCoreFinder employs multithreading and hardware accelerators:

CPUs and GPUs support scalable multithreaded processing enabling exhaustive search over large key and password spaces;
Embedded NaCl-specific vulnerability analysis modules streamline and speed up preliminary selection of key segments;
Automated procedures detect correlations and anomalies in source data to reduce search space size.

This approach significantly outperforms classical brute-force methods relying solely on seed phrase restoration.

Practical Significance and Future Prospects

BitCoreFinder serves as a crucial tool both for recovering access to lost or damaged Bitcoin wallets and for research in modern cryptosystem cryptanalysis. Its ability to identify and exploit vulnerabilities in the widely used NaCl library raises questions about the need for enhanced auditing and review of cryptographic protocol implementations.

Further development of such software could promote more reliable security systems and adoption of protocols with minimal risk from weak cryptographic components.

BitCoreFinder represents a unique system combining deep scientific knowledge of NaCl cryptographic weaknesses with advanced computational technologies to recover lost Bitcoin wallets. By analyzing implementations of Salsa20, Curve25519, Poly1305, SHA-512, and ECDSA/DSA, the tool goes beyond traditional recovery methods, providing reliable and effective access to private keys even when data is partially lost or corrupted.

This comprehensive approach underscores the importance of ongoing analysis and evaluation of cryptographic libraries amid the rapid evolution of blockchain technology and expanding areas of application.

CVE-2018-17144 Vulnerability Specifics

The CVE-2018-17144 vulnerability (related to bitcoin-message and Bitcoin Core) is characterized by a buffer overflow triggered during the processing of transactions with duplicate inputs. This vulnerability allowed remote denial-of-service (DoS) attacks by crashing nodes due to violated transaction input uniqueness checks within a block. Initially manifesting solely as DoS, it was later discovered that some Bitcoin Core versions could let miners double-spend the same bitcoins, theoretically causing “fake” coin creation (inflation).

The root cause was an optimization in Bitcoin Core version 0.14 and later, where the duplicate input check wasn’t fully implemented; instead, only an assert check was done, crashing nodes on error detection. In other versions, this could allow acceptance of transactions involving double spending.

Connection of CVE-2018-17144 to BitCoreFinder

BitCoreFinder analyzes cryptographic and implementation vulnerabilities, including those in libraries like NaCl used in the Bitcoin ecosystem.
Buffer overflows and transaction processing errors akin to CVE-2018-17144 may reveal additional information or open channels for recovering lost keys or seed phrases, especially if such errors cause data leaks or enable cryptanalysis.
BitCoreFinder leverages methods to detect and exploit such vulnerabilities to identify corrupted cryptographic elements, facilitating more effective wallet access recovery.
Buffer overflows and improper transaction handling form part of a broader issue set analyzed by BitCoreFinder to find cryptanalytic hooks for successful key recovery.

In short, buffer overflow caused by duplicate inputs enables remote crashing or erroneous transaction acceptance, and BitCoreFinder uses knowledge and analysis of these vulnerabilities to detect and restore lost Bitcoin keys when implementation mistakes provide additional attack surface and recovery opportunities.

How BitCoreFinder Uses CVE-2018-17144 for Wallet Recovery

Since CVE-2018-17144 causes buffer overflow during transaction processing, resulting in crashes or incorrect transaction acceptance, BitCoreFinder examines such protocol errors and data mishandling for corrupted or incomplete key states.
It employs cryptanalytic techniques to identify these faults and enlarge the search space for private keys and seed phrases, especially if the original data is damaged.
By investigating memory state residues or faulty data structures stemming from the overflow, BitCoreFinder can partially reconstruct private keys.
Multithreaded computation and resource-intensive analysis enable deep cryptographic inspection, memory state recreation, brute-force searches, and correlation analysis based on identified vulnerabilities.
Ultimately, BitCoreFinder goes beyond classical seed phrase input methods, applying advanced cryptanalysis of protocol and implementation flaws—including CVE-2018-17144—which significantly enhances recovery odds even with partial or corrupted information.

Thus, CVE-2018-17144 offers BitCoreFinder an additional entry point for complex cryptanalysis and recovery processes by exploiting implementation error artifacts to discover and reconstruct lost Bitcoin wallet keys, distinguishing BitCoreFinder from traditional recovery solutions.

Types of Vulnerabilities BitCoreFinder Exploits to Find Lost Bitcoin Wallets

Reuse of one-time keys in the Salsa20 stream cipher, leaking information when nonces repeat, lowering key security;
Insufficient randomness (entropy) in Curve25519 private key generation, shrinking possible key space and easing brute-force attacks and cryptanalysis;
Implementation errors in Poly1305 message authentication, including buffer overflow leakage;
Vulnerabilities and failures in SHA-512 hashing, causing instability and potential data leakage with crafted input;
Malleability and implementation faults in ECDSA and DSA digital signatures, allowing signature modification without invalidation and yielding key disclosure information;
Random number generation weaknesses and side-channel attacks (timing and power analysis), increasing key predictability and compromise risk;
Cryptographic data handling errors such as buffer overflows (e.g., CVE-2018-17144), revealing data leaks and corrupted memory states.

BitCoreFinder uses a comprehensive cryptanalytic approach leveraging these vulnerabilities to:

Expand recovery possibilities for private keys and seed phrases, particularly with partially lost or corrupted data;
Automate analysis with multithreading and hardware acceleration to quicken brute-force and computational investigation;
Utilize partial data fragments (keys, passphrases) to narrow search space and improve recovery success rates.

BitCoreFinder stands apart from conventional methods by deliberately analyzing and exploiting cryptographic and implementation faults in NaCl and related algorithms, enabling recovery of wallets otherwise inaccessible by standard recovery techniques.

Source code:

github.com/zoeir