Intro In the previous article, we introduced asymmetric encryption, and particularly the use of public key encryption for transmitting secrets. In this article, we shall take a look at digital signatures, another application of asymmetric encryption. In public key encryption, we used the recipient’s public key to encrypt the message in transit so that only the recipient could decrypt it using their private key. In a digital signature system, the sender encrypts the message with their private key producing a signature.

Introduction In a previous article, we discussed symmetric encryption. In this article we’ll take a look at asymmetric encryption and in particular public key encryption. In symmetric encryption, the same secret key is used for both encoding and decoding messages. However, as we discussed in the previous article, transmitting this secret key securely can be challenging. One solution to this problem is asymmetric encryption, which involves the use of two keys: a public key, which is openly accessible, and a private key, which is kept secret.

Introduction Since the ancient days, a concern for groups of people has been how to securely transmit a secret message securely from one place to another without interception or modification, for example for military purposes. These led to schemes such as the Caesar Cipher being developed. In modern computer systems, computer security relies on confidentiality, i.e. being able to store or transmit information that can only be understood by authorized parties but not adversaries.

Hashing is the process of taking in a block of data of any size and producing a corresponding fixed size representation known as its hash. [dot file] Different types of hashing algorithms exist, but each algorithm always produces hashes of the same size for any inputs it receives. For example, the SHA256 algorithm will always produce a hash of 256 bits (32 bytes) long for any input passed. Other common hashing algorithms are MD5 which produces a 128 bit hash, and the SHA512 that produces a 512 bit hash.