When the data you need to protect is sent across the public internet you need a way to make sure your private data is secure. This is where cryptography is concerned. Cryptography involves developing secret codes as well as figuring out how to break other secret codes.
Within a cyber security context, cryptography is used to convert your data into a secret code to keep your data protected and hidden from prying eyes. This can be achieved by converting it into a secret code only reversible by the intended recipient so that only the intended recipients of a piece of information can read it and nobody else (ideally).
Cryptography is often used in modern computing to protect data from being tampered with in transit or snooped upon or stolen, especially in regards to private data being shared over the web with forms, passwords and shopping transactions.
Cryptography correlates with core principles in securing network communications: Only authorised users can access and alter the data that has been encrypted, and cannot be deciphered by anyone who captures it. This is usually achieved by a hashing function The data encrypted will remain the same as how it was sent by the original author, there will be no alteration in transit. The receiver can rest assured that they have received the identical message that was sent. Only the recipient intended can receive the message as well as guaranteeing the data comes from the source it claims to be from. Symmetric algorithms work with the assumption that everyone uses the same pre-shared key, this key is used to decrypt and encrypt messages, ensuring this data cannot be captured and read. Examples of symmetric algorithms include Data Encryption Standard(DES) and Advanced Encryption Standard. A more flexible approach are asymmetric algorithms, within this approach neither of the communicating party know each other or their secret key and use mathematics to establish a connection based on a combination of their private and shared keys so that only they can exchange messages. Some examples of asymmetric algorithms commonly used in the wild are RSA (Rivest–Shamir–Adleman) and PKI (Public Key infrastructure). Hashing is used to verify that the data is correct and complete and is ensured most commonly by implementing either MD5 or SHA hash generating algorithms. A hash transforms data into a special value that represents the original string of data. Passwords get stored by hashing them and comparing a hashed version of the plaintext sent over a password field to the hash on the database. This saves businesses from storing user passwords in plain text which is helpful if they become compromised, because then only the hashed data is leaked which is difficult to crack.Cryptanalysis is the practice of breaking codes to test how strong they are. Cryptanalysts break codes for the military, government bodies and businesses to test weaknesses within their security. Similar to the concept of ethical hacking and penetration testing, you can only prove your security is good by attacking it or cracking it in the same way a hacker would. Therefore there is a huge need for cyber security experts to try and break these encryption methods before a hacker does.