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Serious bugs and vulnerabilities in the pybitcointools library

The pybitcointools library, created by Vitalik Buterin for working with Bitcoin in Python, has been a popular and widely used tool. However, as with any software, serious bugs and vulnerabilities were discovered in it, which could lead to loss of funds or other critical consequences.

Vulnerability in the function of creating private keys (2014)

In 2014, a serious vulnerability was discovered in the library’s create_privat_key function. This function generated private keys using an inappropriate source of entropy, making them predictable and vulnerable to key guessing attacks.

As a result of this vulnerability, attackers could calculate private keys generated using pybitcointools and gain access to the corresponding Bitcoin wallets. This resulted in loss of funds for some users.

Error in the implementation of the transaction processing algorithm (2015)

In 2015, a critical error was discovered in the implementation of the algorithm for processing Bitcoin transactions in pybitcointools. This bug could lead to incorrect transaction validation, potentially allowing attackers to create invalid transactions and compromise the integrity of the blockchain.

Although this vulnerability was not directly used for attacks, it posed a serious threat to the security of the Bitcoin system and required immediate patching.

Outdated code and lack of active support

Besides specific bugs and vulnerabilities, the pybitcointools library has suffered in recent years from outdated code and a lack of active support and development. This created additional security risks and compatibility with new versions of Bitcoin and other cryptocurrencies.

For these reasons, many developers and projects have gradually abandoned the use of pybitcointools in favor of more modern and actively maintained libraries such as bitcoinlib or python-bitcoinlib.

Despite the problems found, pybitcointools has played an important role in the development of the Bitcoin ecosystem and demonstrated the need for rigorous testing and auditing of cryptographic software. The experience with this library provided valuable lessons for the developer community and contributed to raising security standards in the cryptocurrency industry.

The pybitcointools library, developed by Vitalik Buterin, is one of the early software tools for working with Bitcoin and other cryptocurrencies in Python. Despite its popularity during certain periods, this library contains a number of serious errors and vulnerabilities that developers and users should be aware of.

1. Security gaps

One of the main problems of the library is the use of outdated and potentially vulnerable encryption and key generation methods. For example, the library used simple methods to generate pseudo-random numbers, which could lead to predictable keys and make it easier for attackers looking to steal funds.

2. Errors in the code

Numerous errors related to input data processing and operations execution were discovered and corrected. These errors could lead to incorrect calculations of addresses or transactions, which in turn could lead to financial losses.

3. Problems with support and updates

The lack of regular updates and support also added risks, since the cryptocurrency market is developing very quickly and security standards are constantly tightening. Code obsolescence can lead to vulnerabilities as new attack methods and improvements in blockchain technology emerge.

4. Lack of proper documentation and testing

Insufficient documentation and limited code testing can cause developers to misuse the library, which also increases the risk of errors and vulnerabilities.


Using the pybitcointools library nowadays requires caution. Developers using this library are encouraged to thoroughly review and test their code, and consider migrating to more modern and actively maintained libraries. It is important to remember that security is a priority in the world of cryptocurrencies, and using outdated tools can lead to serious financial losses.

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