programming chelahmy

A blockchain is a chronicle of signatures . Everyone can see the signatures but no one can afford to alter them. As a new block of signatures joins in as time passes the blockchain security as a whole becomes stronger. Blockchain is protected by public cryptography with no need of a central supervision. By design, altering any of the signature will be a very expensive undertaking. So expensive as comparable to the cost of breaking a vault of gold, which act of breaking in is much more expensive than the gold itself. All signatures are well-verified prior to being kept secured into a blockchain. Hence, all signatures in a blockchain can be trusted without requiring any third party verification. The principle of blockchain was made popular through the Bitcoin  whitepaper  by an illusive Satoshi Nakamoto . Even though the two words block and chain were never mentioned as one word in the whitepaper the essence of blockchain was described through out the document. The Bitcoin blockchain

Every data has a signature  which can be derived mathematically. All data of any size can be digested into fixed-size signatures. The signatures can be used to identify the data. Unique data has unique signature. Cryptographic hashing is a mathematical technique to hash or digest a data to reveal its signature. Digesting the same data always produce the same signature. Any minor change on the data will produce significantly different signature. A changed data is a different data. Data signature, hashing or digesting makes it possible for the data to be represented by its signature into a subsequent signing by combining it with one or more data signatures to produce a new signature representing a larger data set. Eventually, all data can be digested in chunks to produce a single signature. A signature can be verified by hashing the same data again which will produce the same signature. This introduces data signing-verification concept. In a communication between two parties, the