SHA-256 vs. Keccak-256 hashing algorithm =

Computers make full use of hash functions, without you realizing it. The password for your Facebook account? It is stored as a hash on Facebook’s server. The same goes for many other dates. Blockchains and cryptocurrencies also use hashing algorithms. For example, Bitcoin’s blockchain uses the SHA-256 algorithm and Ethereum uses Keccak-256.

Both algorithms are very similar. However, there are a number of major differences between the algorithms. If you want to know more about how these blockchains and cryptocurrencies work, it is interesting to take a look at these differences. Below we explain more about SHA-256, Keccak-256 and the differences between these hashing algorithms .

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  • View quickly
  • What is hashing again?
  • What is SHA-256?
    • SHA-256 hash
    • What is SHA-256 used for?
    • Which blockchains use SHA-256?
    • SHA-256 on Bitcoin
  • What is Keccak-256?
    • Usage of Keccak-256
    • Keccak-256 on Ethereum
  • SHA-256 vs. Keccak-256
  • Conclusion

What is hashing again?

Hashing is a way of converting data into a unique code, which resembles a random string of characters . The process of converting data into a hash is done according to a specific algorithm. This means that the characters in a hash are actually not as random as many people think.

The algorithm behind the hash function works according to a certain logic, so the algorithm will always ensure that the same content returns the same hash. In the case of a secure hashing algorithm, it is impossible to retrieve the content of the hash. This means that a secure algorithm works in only one direction. There are also broken algorithms where the logic of the hash function is obsolete. It is then possible to retrieve the content from the hash, such as MD5.

We previously wrote an article about the most important and (un)safest hashing algorithms, which you can read here.

What is SHA-256?

SHA-256 is a specific hashing algorithm within the SHA family (which stands for Secure Hashing Algorithm), which is used to convert data into a hash . The algorithm was devised by the National Security Agency (NSA) in 2001 as a precursor to SHA-1. Much needed, because it became clear around that time that SHA-1 was not secure enough. Not much later, the algorithm was broken, so that SHA-1 is no longer used.

The hashing of data is done according to a secret algorithm, which makes it impossible to trace the original content of data from the hash. It is only possible to convert data to a SHA-256 hash. Such a hash consists of 256 bits. The content should be under 264 bits to keep the hash as random as possible.

Many other algorithms within the SHA family have emerged, such as SHA-384 and SHA-512. Yet SHA-256, despite being invented way back in 2001, is still considered one of the most secure hashing algorithms in the world . In the video below you will learn more about SHA-256.


SHA-256 hash

A SHA-256 hash always consists of 256 bits. Suppose we convert ‘all-over-crypto’ to a hash, according to the SHA-256 algorithm, the hash looks like this:


If we now remove the ‘L’, the hash will look like this:


As you can see, we get a completely different output when we remove just one letter. This high degree of ‘randomness’ makes SHA-256 one of the most secure algorithms in the world. Here you can make your own SHA-256.

What is SHA-256 used for?

The SHA-256 algorithm is used for several functions. One of its most important functions is password hashing . This means that a password is first converted to a SHA-256 hash before it is stored in a database. This way the password is protected against anyone who has access to the database.

In addition, SHA-256 is also commonly used for SSL handshakes . This is the contact between a web server and web browser. When a website has an SSL certificate, a secure connection can be established between the website and the browser. This connection is set up using cryptography and hashing, using SHA-256.

Furthermore, SHA-256 is also used for integrity verification and digital signature verification . SHA-256 is used to check that data looks the same when received as when sent, without viewing the content.

In blockchains and cryptocurrencies, SHA-256 is used to verify the integrity of a file using asymmetric encryption . It is an important component for digital signatures, which is used by Bitcoin, among others.

Which blockchains use SHA-256?

  • Bitcoin (BTC)
  • Litecoin (LTC)
  • EOS (EOS)
  • Stellar (XLM)
  • Bitcoin Cash (BCH)
  • TRON (TRX)
  • Dash (DASH)
  • NEO (NEO)
  • Zcash (ZEC)

SHA-256 on Bitcoin

SHA-256 is the hashing algorithm used by the Bitcoin blockchain. That happens for mining, where miners check transactions and create new blocks . To do this, they must provide computing power to guess as many outcomes (hashes) as possible until the correct hash is found. The hash rate plays an important role in this. This is the number of combinations a miner can guess per second, and is often influenced by the quality of the hardware.

Bitcoin wants each block to be guessed at roughly the same speed, as a faster hash rate makes the blockchain more vulnerable to outside attacks. The protocol can adjust the hash rate automatically. It is important to remember that a block containing transactions is converted to a SHA-256 hash.

SHA-256 also creates a chain of blocks , where the hash of each previous block is appended to a new block, which is then converted to a hash. When someone tries to change the contents of a block, the block’s hash will change and a break in the chain will occur. The nodes in the network will not accept this version of the blockchain, keeping the blockchain secure.


What is Keccak-256?

Keccak-256 is a hashing algorithm based on the SHA-3 family and is designed to convert an input into a hash of 256 bits (bytes32) . It’s a one-way hash function, meaning you can convert an input to a hash, but not extract the content from the hash. This means that Keccak-256 is a secure algorithm and can therefore be used for various security purposes.

Let’s take a look at what the output of Keccak-256 looks like. If we convert ‘all-over-crypto’ to a Keccak-256 hash, the output will look like this:


If we remove one ‘L’, then ‘alesovercrypto’ remains, and the Keccak-256 hash looks like this:


Also now we see that the output is completely different after we remove only one character. This makes the Keccak-256 a secure algorithm, as it makes it virtually impossible to break the algorithm.

Within the Keccak family you will also find other algorithms, such as Keccak-224, Keccak-384 and Keccak-512. If you want to learn more about what Keccak-256 is and how this hash function works, you can watch the video below.


Usage of Keccak-256

Keccak-256 is a hashing algorithm mainly and only used by the Ethereum blockchain . Just like Bitcoin, this blockchain uses a hashing algorithm to store sensitive data. Like any other system, whether centralized or decentralized, it is important to secure data. Instead of keeping data in its original form, it is hashed and stored as a hash, meaning no one can see the actual data.

Algorithms such as SHA-256 are commonly used for storing passwords and verifying data integrity, while Keccak-256 is used specifically by the Ethereum blockchain. Why does Ethereum use such a specific hash function? That is because the decentralized system of Ethereum has different requirements for the security of the data than central systems. SHA-256 is basically designed for central systems, because blockchains did not exist in 2001.

Keccak-256 on Ethereum

Keccak-256 is an important part of the Ethereum blockchain. It is used for digital signatures . You create this signature by combining the public and private key. Keccak-256 is used as the hashing algorithm for these keys, which means that the algorithm plays an important role in the security of Ethereum.

On the blockchain, transactions are aggregated and converted to a hash using Keccak-256 . This guarantees the integrity of transactions and changes on the blockchain can be noticed immediately. If a hacker or criminal tries to change a block, the hash of the block changes, which is immediately noticed by all nodes in the blockchain’s network. This makes Ethereum’s history immutable.


SHA-256 vs. Keccak-256

Below is an overview of the differences between SHA-256 (used by Bitcoin) and Keccak-256 (used by Ethereum).



SHA-256 was invented in 2001 and is therefore a ‘tried’ hashing algorithm.

Keccak-256 was launched in 2007, making it a ‘less experienced’ algorithm than SHA-256.

This algorithm was invented and developed by the NSA. This is the American security service, so you can say that they had a certain intention in developing the algorithm.

The algorithm was devised and developed by a group of scientists. They developed the algorithm because they wanted a variant of SHA-256 optimized for Ethereum.

SHA-256 cannot handle large amounts of data. Ideal for passwords, but less suitable for large amounts of transactions.

The sponge function of Keccak-256 allows the algorithm to process large amounts of data. Ideal for processing large volumes of transactions.

The SHA-256 algorithm is used for data and password security. It has a wide range of use.

Keccak-256 is only used for cryptocurrencies. It has a very narrow and centered area of use.

Because you have to go through more steps to generate a hash, SHA-256 is less efficient and slower. Less suitable for blockchains that have to process large amounts of transactions.

Keccak-256 is more efficient and can hash large amounts of data faster, allowing a blockchain using Keccak-256 to process more transactions and faster. Ideal for blockchains that want to be scalable.

From the differences, you can see that Keccak-256 is optimized for crypto. Still, most cryptocurrencies use SHA-256. Why is it like that?

When looking at the list of blockchains that use SHA-256, these are mainly ‘old’ blockchains that were launched between 2009 and 2013. After this, blockchains increasingly focused on scalability. For this they developed a hashing algorithm themselves or they used an algorithm that was fairly new. A new algorithm is often faster than old algorithms, but may also be less secure.

Keccak-256 is therefore more efficient for blockchains such as Ethereum, while Ethereum has suffered from scalability problems in recent years. However, these problems were not caused by the hashing algorithm, but by other factors such as the consensus mechanism.


Hashing algorithms are extremely important for our technology. Not only today, but also in the past and in the future, hashing plays an important role. Because technology is constantly changing, it is important that we have different hashing algorithms. A hashing algorithm that is still safe today could just be broken tomorrow (although the chance is small).

SHA-256 is an important hashing algorithm that has been used since 2002. Keccak-256 is based on the SHA algorithms, but is mainly optimized for blockchains and cryptocurrencies. Particularly for Ethereum. While SHA-256 is used by many ‘old’ blockchains such as Bitcoin and Litecoin, you can see Keccak-256 as a newer algorithm that can process more transactions faster. That is one of the reasons Ethereum uses the Keccak-256 algorithm.

Are you looking for more information or do you have any questions about SHA-256, Keccak-256 or other crypto topics? Or would you like to meet other crypto enthusiasts? In the free Discord channels of our product Money Mastery from AllesOverCrypto you can ask questions and talk to thousands of other crypto enthusiasts. Do you have other crypto related questions? The easiest way is to look up your question in our FAQ. What you can also do is that you google your question + AllesOverCrypto. Please let us know what you think about these hashing algorithms.

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