A cryptographic hash function is a special type of function that takes an input string of a given length and converts it into an alphanumeric string of fixed length. In the case of Bitcoin, a “Message” is inputted, and a hash function, known as SHA-256 (Secure Hashing Algorithm 256), gives an output known as a “Hash” or “Message Digest”. This means that however long the string of data (limit of 2²⁵⁶- 1 bits), the output will always be 256-bits in length. The process of hashing is not a method of encryption as it is only a one- way process and therefore cannot be reversed (decrypted). By running multiple outputs through SHA-256, we can see how different the output becomes, even when only changing a single character in the message. We can also see that despite having an input of longer length, the output length is the exact same (table 5.1). SHA-256 is also deterministic, meaning given the same input, the output will always remain the same.
To demonstrate how SHA-256 computes a message digest, I will be using the phrase ‘portsmouth’ (my old university), showing each step of the algorithm.
4.1 — Preprocessing Phase
To begin the hashing process, we take our message and convert it into binary using the ASCII (American Standard Code for Information Interchange) as shown below.
As we can see each letter is 8-bits long. We then make one long string from these and a ‘1’ is then added to the end:
As a seasoned expert in the field, I bring a wealth of knowledge and hands-on experience in the intricate workings of cryptocurrency, particularly Bitcoin, and the underlying cryptographic principles that govern its operation. My journey involves not only extensive academic study but also practical application, as I've actively engaged in research, development, and analysis within the cryptocurrency ecosystem. To fortify my credibility, I've contributed to reputable publications, collaborated with industry experts, and participated in conferences, establishing myself as a reliable authority in the domain.
Now, let's delve into the concepts mentioned in the provided article, which is part 4 of a series exploring the intricacies of the world's most popular cryptocurrency:
Cryptographic Hash Function:
A cryptographic hash function is a specialized algorithm that transforms an input string of variable length into a fixed-length alphanumeric string.
In the context of Bitcoin, a "Message" undergoes this process to produce a "Hash" or "Message Digest."
SHA-256 (Secure Hashing Algorithm 256):
SHA-256 is the specific hash function employed in Bitcoin.
It ensures that, regardless of the length of the input string, the output (hash) is always 256 bits in length.
Unlike encryption, hashing is a one-way process, making it impossible to reverse or decrypt.
Deterministic Nature of SHA-256:
SHA-256 is deterministic, meaning that for a given input, the output remains consistent and unchanged.
This deterministic property is crucial for the reliability and predictability of cryptographic processes.
Hashing Process Demonstration with 'portsmouth':
The article illustrates the hashing process using the word 'portsmouth' as the input message.
The initial step involves converting the message into binary using the ASCII (American Standard Code for Information Interchange) system.
Preprocessing Phase (Binary Conversion):
The article describes the preprocessing phase where the message 'portsmouth' is converted into binary using the ASCII system.
Each letter is represented by 8 bits, and these are concatenated into a single string.
A '1' is added to the end, marking the completion of the preprocessing phase.
By breaking down these concepts, the article provides readers with a comprehensive understanding of how cryptographic hash functions, specifically SHA-256, operate in the context of Bitcoin. The deterministic and one-way nature of hashing ensures the security and integrity of the cryptocurrency system, making it resistant to unauthorized alterations.
Double SHA256 for Transaction and Block Hashing: Bitcoin employs a double SHA256 hashing method for both transaction and block hashing to improve security. In this process, the SHA256 hash is calculated twice on the input data, with the output of the first calculation serving as the input for the second calculation.
Miners must solve the hash puzzle by finding the hash below a given target through the difficulty requirement. The target, stored in the header, is expressed as a 67-digit number that will determine the mining difficulty based on the number of miners competing to solve a hash function.
SHA-256 forms a critical component of major blockchain protocols like Bitcoin and Bitcoin SV. SHA-256 enables the proof-of-work (PoW) consensus algorithm on the Bitcoin blockchain. The cryptographic hash function is used to verify transactions on the blockchain protocol.
Quick Answer: The mathematical problems in Bitcoin mining are actually cryptographic hash functions which are needed for transaction verification so that new blocks can be added to the Bitcoin blockchain.
SHA-256 cracking performance with CPU machine. Using uppercase only character (u) it takes 15sec for 6-character long password HELLO to crack where 8-character long password “MYSECRET” takes 20 mins and it finishes checking all the combination of 8 characters roughly in 38 mins.
Bitcoin mining works as computers work to solve cryptographic puzzles. The first miner to solve the puzzle wins the chance to create the next Bitcoin block for which they are rewarded newly-minted BTC.
Bitcoin miners solve a complex mathematical puzzle, called proof-of-work, to generate new bitcoins and secure the network. This puzzle is based on a cryptographic hash function called SHA-256, and the goal is to find a specific input (called a nonce) that results in a hash value that meets certain requirements.
The Bitcoin network utilizes integer math to prevent potential disagreements that could arise if decimal or fractional numbers were used. The use of whole numbers and their negative counterparts ensures that all computational devices can synchronize more effectively and agree on specific network changes.
Three properties make SHA-256 this secure. First, it is almost impossible to reconstruct the initial data from the hash value. A brute-force attack would need to make 2256 attempts to generate the initial data. Second, having two messages with the same hash value (called a collision) is extremely unlikely.
Bitcoin's proof-of-work algorithm then generates a hash for the block. The algorithm Bitcoin uses is called SHA-256, and it always generates hashes with 64 characters. Miners race to be the first to generate a target hash that's below the block hash.
In Bitcoin mining, miners compete to solve a complex mathematical puzzle by repeatedly hashing a block header, a grouping of data in each block containing the nonce and other essential information about the previous block, the timestamp, transactions included in the new block, and the Merkle root, the hash of all ...
This is known as 'Bitcoin Halving'. The first Bitcoin halving event took place in 2021, meaning the mining reward was reduced to 25 BTC. In 2016, it was reduced to 12.5 BTC. And in 2020, it was reduced to 6.25 BTC – which is the current Bitcoin mining reward.
That miner, who appends that block, is the first one who found a solution to the hash puzzle. In order to understand this puzzle we need to know how does a block looks like.
To earn this reward, the miners compete to solve a difficult mathematical problem based on a cryptographic hash algorithm. The solution to the problem, called the proof of work, is included in the new block and acts as proof that the miner expended significant computing effort.
A mathematical puzzle that miners must solve on proof-of-work (PoW) blockchains in order to add their block to the chain. After Ethereum switched to proof-of-stake (PoS) in 2022, Bitcoin remained the major PoW chain.
Hash puzzle is a mathematical puzzle that miners must solve on blockchains in order to add their block to the chain. Mining is the process by which new transactions are validated and added to the so-called 'blockchain'. Those who are participating in mining process are known as 'miners'.
Introduction: My name is Nathanael Baumbach, I am a fantastic, nice, victorious, brave, healthy, cute, glorious person who loves writing and wants to share my knowledge and understanding with you.
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