Cryptography is the study of secure communication techniques that only allow the sender and the recipient to decipher the message or view its contents. Breaking down the terminology, crypt- means “hidden” while -graphy means “writing.” These secure information and communication techniques are derived from mathematical concepts that use algorithms. These algorithms help to generate cryptographic keys, confidential communications such as bank transactions and various methods of verifying data privacy, especially when browsing the internet. Although cryptography is closely associated with encryption, it is more than that. Encryption is putting ordinary text into ciphertext when sending and later and back again to the original form upon reaching the sender. In addition to that, cryptography includes the concept of making images unintelligible by merging or using microdots.
Cryptography is essential because it covers three fundamental principles of information and communication security: authentication, integrity and confidentiality (Tuncay, 2019). Firstly, by authentication, cryptography identifies the origin of the information. It is much safer to communicate if one knows the source of information. Authentication offers certificates known as digital IDs to identify someone. This special keys exchange are to be used accordingly by the sender to prove their identity. The receiver can then judge if the sender is legit or not.
Secondly, cryptography ensures the integrity of data by providing codes and digital signatures to ensure that whatever we receive if from the intended person. This way, nobody can impersonate you. For instance, it is easy to forge an email but very hard to forge a digitally signed email (Industry News, 2014). Similarly, it is difficult for someone to manipulate the information that you have digitally signed.
Thirdly, cryptography ensures confidentiality by using cypher when sending sensitive or secret information over a network. Confidential information, for instance, could be credit card details, financial transactions or personal records. Cypher is an intelligent system that encrypts and decrypts one’s information. Before storing data on a drive or sending it through a network, the cypher can encrypt it and turn it unintelligible. If one needs the data again, they could use a cypher to decrypt it. The sender is the only person that can be able to decrypt the data, and so has to ensure that only the designated recipient can decrypt it. In addition, cryptography offers non-repudiation. Nowadays, it is common that senders deny the origin of a particular piece of information to someone. By the use of digital signatures, cryptography ensures that senders cannot deny that they sent the information (Tuncay, 2019).
Cryptography has many applications in everyday life. First is electronic money, also known as electronic cash or digital cash. It involves sending or receiving payment electronically, which can be anonymous or identified. Anonymous applications do not disclose the customer’s identity. Instead, they are based on blind signatures schemes. They are based on an electronic analog of cash. On the other hand, identified projects have more general schemes of signatures. They are based on an electronic analog of debit or credit cards. However, there are some approaches that may be termed as a hybrid, whereby the payments are anonymous to the merchants but not to the bank, or can also be anonymous to both, although, sequences of transactions can be traceable. Cryptography in such money schemes is used to protect transaction data such as account numbers or transaction amount. Digital signatures replace the handwritten signatures or credit card authorizations.
Secondly, cryptography is used in messaging apps, for instance, Snapchat. What makes the app so popular is that the messages that the users send to each other are on set timers for viewing once or else the messages become inaccessible (Rishabhreddy, 2019). The messages are encrypted in-transit, that is when they reach the Snapchat servers. Once the intended recipient opens the messages, they are deleted from the servers. At this stage, the message cannot be retrieved from the servers by anyone for any reason. However, messages that have not been opened are stored in the server for 30 days in case the messages are required by law.
Thirdly, cryptography is used for authentication and encryption of emails and file storage applications. If a sender encrypts a message with their private key and the recipient is able to decrypt it with the sender’s public key, then the recipient should considerably trust that the message came from the designated sender. The challenge is that public keys are associated with their users in a trusted manner. This poses a data security threat should the sender be not who they say they are. To address the issue, the standards community introduced a certificate. This certificate contains the name and public key of the subject for whom the certificate is being issued to, as well as some time stamps. This way, the recipient will know that the public key is good as the issuer of the certificate will have a certificate themselves. Various software packages such as PGP (Pretty Good Privacy) have been developed on this basis. The software provides encryption, data compression, digital signatures and email compatibility (Rishabhreddy, 2019).