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Can Brute Force Attacks Crack Bitcoin Private Keys?

June 23, 2022

In practical terms, brute force attacks are not a successful method for cracking Bitcoin private keys. Below, we’ll explain why (and how has helped Bitcoin holders restore access to their funds).

A brute force attack attempts all possible combinations of numbers and letters. The language is telling: a true brute force attack has no logic outside of “try everything and hope that something works.” 

Eventually, brute force attacks do work, provided that you perform enough attempts. Of course, simple math dictates whether brute force attacks are realistically possible on a reasonable timeline.

If you’ve lost access to your Bitcoin wallet, hope isn’t lost. We’ve successfully recovered private keys in certain situations. Call 1-800-237-4200 or submit a case to connect with a Bitcoin recovery technician. 

The Limits of Brute Force Private Key Attacks

Bitcoin uses a private key consisting of a 256-bit hexadecimal encoded number. If the private key matches the public key, the attacker would gain access to the wallet in question — but that would involve guessing all numbers between 1 and 2^256. Modern computers aren’t capable of guessing all numbers between 1 and 115 quattuorvigintillion (and yes, quattorvigintillion is the real number name) within a human lifetime. 

The number of potential bitcoin keys is greater than the number of atoms in the known universe. Even with hundreds of powerful computers working on a single private key, a brute force attack could take millions of years. 

That may change over time as computers become more powerful. Some IT professionals believe that 256-bit passphrases will be crackable by the year 2040, which would present some serious issues for future Bitcoin users. 

That’s just a theory, however, and it’s controversial — for the time being, this type of crack is effectively impossible unless some portion of the private key is known.

Can Brute Force Attacks Crack a Bitcoin Wallet Seed Phrase?

While private keys are tremendously secure, Blockchain passphrases (or seed phrases) are less robust against cracking. Note here that “less” is relative — passphrases are still mathematically impossible to guess, but several factors might make them a viable target. 

Passphrases are a sequence of 12-24 readable words presented in the English language, which are used to determine the private key. Because passphrases use English words, they can be cracked with a dictionary attack. Unlike a brute force attack, a dictionary attack uses likely combinations of characters (in some cases, literally an English dictionary) to reduce the number of potential passphrases.

However, 12-word seed phrases are still extremely secure. Hacking a seed phrase is effectively impossible unless some of the words from the phrase are known to the user. If the user does know some of the words from the seed phrase, they can convert the wallet file into a hash and attempt a targeted attack to crack the phrase.

We’ve successfully recovered seed phrases in this manner. Put simply, if you know most of the words of your phrase, you’ve got a decent chance of getting access to your cryptocurrency — regardless of whether you remember the words from the passphrase in the correct order. 

Bitcoin Wallet Password Recovery

Another option is to guess the password or PIN number of the software used to create the wallet file. Some wallets do not have passwords apart from the seed phrase.

This is often the most successful method for cracking Bitcoin wallets, as it depends on the user’s password practices. Simple passwords can be guessed quickly, especially if the user knows a portion of the password or can create a list of likely passwords. 

However, some software limits the number of password attempts to prevent brute force attacks. Once the number of attempts has been exceeded, the seed phrase will be necessary for accessing the funds.

Restore Access to Your Bitcoin Wallet is the world leader in professional media repair and data recovery services. Many of our engineers were early adopters of crypto — including Bitcoin — and we’ve developed proprietary techniques to help investors restore access to lost assets.

Our services feature a no data, no charge policy. If we’re unable to restore access to your cryptocurrency, you won’t pay. With fast turnaround times and industry leading technology, we offer a secure way to restore lost Bitcoin while maintaining your privacy. 

Get started by calling 1-800-237-4200 or click here to submit a case online.