Cryptography, Encryption, Hash Functions and Digital Signature

Cryptography is at the heart of Blockchain technology. At this post, I will try to explain some of the basics of Cryptography, Encoding,Encryption and Digital Signature.

Encoding is the process of applying a specific code, such as letters, symbols and numbers, to data for conversation into an equivalent cipher.

The difference between encoding and encryption is that encryption needs a key to encrypt/decrypt.

Cryptography

Cryptography is the practice and study of secure communication in the presence of third parties.[1] In the past cryptography referred mostly to encryption. Encryption is the process of converting plain text information to cipher text. Reverse is the decryption. Encryption is a mechanism to make the information confidential to anyone except the wanted recipients. Cipher is the pair of algorithm that creates encryption and decryption. Cipher operation is depends on algorithm and the key. Key is the secret that known by communicants. In addition, there are two types of encryption by keys used:

Symmetric Key Algorithms
Symmetric key algorithms (Private-key cryptography): same key used for encryption and decryption. (AES, DES etc.) (AWS KMS uses Symmetric Key Encryption to perform encryption and decryption of the digital data)