What You Need to Know About the SHA-256 Algorithm
The SHA-256 algorithm is a cryptographic hash function. This algorithm converts a message (data) into a fixed-length cryptographic digest (hash value). The SHA-256 algorithm is especially used in security applications such as digital signature, authentication and integrity checking.
The name of the SHA-256 algorithm is an abbreviation of "Secure Hash Algorithm 256". This algorithm is one of the sub-encryption functions of the SHA-2 algorithm developed by the US National Security Agency (NSA). The SHA-2 algorithm replaced the SHA-1 algorithm in 2001.
Every data encrypted with the SHA-256 algorithm is reduced to 64 characters or 256 bits, regardless of the size of the input. This makes it easier to store and transmit data. Also, the same input always generates the same hash value. This can also be used to verify that data has not been altered or corrupted.
One of the most important features of the SHA-256 algorithm is that it is unidirectional. In other words, it is not possible to access the input from the hash value. This increases the privacy and security of data. But this feature also makes the SHA-256 algorithm harder to crack.
There are two methods for cracking the SHA-256 algorithm: brute force attack and birthday attack. A brute force attack is trying to find an entry that matches the hash by trying all possible entries. A birthday attack is based on different inputs producing the same hash value.
The SHA-256 algorithm's resistance to brute-force attack is due to its 256-bit length. It would take 2^256 different tries to find an entry that matches a hash of this length. This is practically impossible.
The resistance of the SHA-256 algorithm to the birthday attack is due to the birthday paradox. This paradox shows that two randomly selected people in a group are more likely than thought to have the same birthday. Similarly, the probability of two randomly selected entries having the same hash value is higher than thought.
According to the birthday paradox, in an algorithm with a hash value of 2^n bits, when approximately 1.2√(2^n) different inputs are produced, there is a 50% probability that the two inputs will produce the same hash value. This means about 2^128 different entries for the SHA-256 algorithm. While this is also easier than a brute force attack, it is still practically impossible.
The SHA-256 algorithm is used in many areas today. The most well-known of these is Bitcoin. Bitcoin uses the SHA-256 algorithm to both verify and mine transactions on the blockchain. Mining is the process of generating new Bitcoin and adding new blocks to the blockchain. Miners try to find the nonce, a value that they can change without corrupting the data in the block. This value ensures that the hash of the block conforms to a certain rule. This rule is that the hash of the block starts with a certain number of zeros. This number is called the difficulty level and is adjusted according to the mining power in the network.
The SHA-256 algorithm is used by many cryptocurrencies other than Bitcoin. Some of these are Litecoin, Bitcoin Cash, Zcash and Dogecoin. In addition, the SHA-256 algorithm is used in internet protocols such as SSL/TLS, encryption programs such as PGP, and version control systems such as Git.
The SHA-256 algorithm is one of the most secure and common cryptographic hash algorithms today. This algorithm is used in many areas to ensure the integrity, confidentiality and security of data. However, the SHA-256 algorithm also has limitations. For example, with the development of quantum computers, the fragility of this algorithm may increase. Therefore, more powerful and new cryptographic hash algorithms may be needed in the future.