Before starting with Hashing in Cryptography, we may recollect the types of Cryptography that were discussed in detail in the previous session. Today we look at the Hashing Techniques and how It helps in encrypting the data and information across a distributed network.
The topics covered for Hashing in Cryptography
What is Hashing in Cryptography?
A hash function is a series of mathematical steps or algorithms that you can perform on some input data, resulting in a fingerprint, or digest, or simply, a hash. There are basic hash functions which are not used in Crypto transactions and cryptographic hash functions that have widespread applications in Blockchains. Although Basic Hash Functions are not a part of the Crypto, but in order to understand Crypto Hash, we need to have an overview of the basic Hash functions.
Basic Hash Functions
Under Hashing in Cryptography, a really basic hash function might be ‘Use the first character of the input’. So using this function you’d get: Hash (‘What time is it?’) => ‘W’. The input to this function is ‘What time is it?’ and is sometimes called the preimage or the message. The output of this function is ‘W’ and is called the digest, the hash value, or simply the hash.
Hash functions are deterministic because the output is determined by the input. If a function is deterministic, it always produces the same output for any given input. All mathematical functions are deterministic (adding, multiplying, dividing, etc).
Cryptographic Hash Functions
A cryptographic hash function is special and has some characteristics that makes it useful in cryptography and for cryptocurrencies. It is deterministic so the same message always results in the same hash and is quick to compute the hash value for any given message. A small change to a message should change the hash value so extensively that the new hash value appears uncorrelated with the old hash value.
Digital Signatures in Hash Functions
Under Hashing in Cryptography, digital signatures are an important tool to authenticate and secure the transactions over a distributed network. Digital signatures are used extensively in Bitcoin and blockchains for creating valid transactions ‘signing’ transaction messages to move coins from your account to someone else’s.
As a part of Hashing in Cryptography, digital signature is created by taking the message you want to sign and applying a mathematical formula with your private key. Anyone who knows your public key can mathematically verify that this signature was indeed created by the holder of the associated private key (but without knowing the private key itself). So, anyone can independently validate that this piece of data was signed by the private key holder of this public key.
In the next session, we take a closer look at the Hashing in Cryptography with respect to the digital signatures that are used as a security and authentication tool.
Various type of Cryptography methods available in Blockchain
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