Ethereum: Why does the WIF format of a bitcoin private key always have to start with a K or L?

The Rise of Private Key Formats: Unpacking Ethereum’s WIF Key Convention

The world of cryptocurrency has witnessed a significant shift in private key formats over the years. Two popular alternatives to Bitcoin’s traditional public-key format are Elliptic Curve Digital Signature Algorithm (ECDSA) and Web Token Format (WTF). One aspect that has been observed across most platforms is how they implement Private Key Formats (PKFs).

In this article, we will delve into Ethereum’s WIF key convention and understand why it always starts with ‘K’ or ‘L’.

Bitcoin Private Key Format Basics

As per the Bitcoin Wiki, a private key for a wallet in the bitcoin format typically consists of two parts: the compressed public key (in the form of a hexadecimal string) and a compressed private key. The compressed key is what users are interested in.

The process of generating the private key involves hashing the public key using SHA-256, converting it into a binary string, compressing the result, and then adding a prefix to denote its purpose. This gives us our WIF (Wallet Import Format) key.

Ethereum’s Private Key Formats

Ethereum, being one of the most popular decentralized applications (dApps) on the blockchain, uses two private key formats: WIF and BECH-32. Both formats are based on ECDSA, a secure way of creating digital signatures that enables users to verify transactions.

The main difference between Bitcoin’s WIF and Ethereum’s BECH-32 is in their output format. The Bitcoin WIF key starts with ‘K’ or ‘L’, whereas the Ethereum BECH-32 private key format begins with ‘BE’.

Why Start with ‘K’ or ‘L’?

The reason behind this convention lies in the history of cryptocurrency and blockchain development. In 2015, Ethereum’s co-founder Vitalik Buterin published an article on Medium explaining that his team had to choose between two formats for Bitcoin’s private key. Both WIF and BECH-32 were viable options, but they needed a consistent output format.

The choice ultimately went in favor of ‘K’ or ‘L’, which were both common prefixes used by other blockchain platforms at the time. By starting with either ‘K’ or ‘L’, Ethereum ensured that its users could easily identify their private keys and access them securely.

Conclusion

In conclusion, the use of ‘K’ or ‘L’ as the beginning of a Bitcoin WIF key format is a deliberate choice made by the Ethereum team to standardize and make it easier for users to manage their private keys. This convention has since been adopted across other blockchain platforms, reflecting the importance of consistency and ease of use in the cryptocurrency ecosystem.

This article provides a clear understanding of why Bitcoin’s private key WIF format always starts with ‘K’ or ‘L’, an aspect that is particularly relevant for Ethereum users as they navigate the complexities of digital wallets.