Cryptography is the practice and study of techniques for secure communications against a third party “adversary”. Modern cryptography is underpinned by mathematics and “computational hardness assumptions”, cryptographic algorithms are designed to require so much effort to break as to be invisible even to an adversary with significant resources such as a nation-state.
Technipages Explains Cryptography
Cryptography has many different use cases in modern life, such as data confidentiality, keeping data private from people that should not be able to access it, cryptography can ensure that a nosy neighbour cant “listen in” to your conversations.
Data integrity, ensuring that the data does not get modified between writer and reader, historically ISPs have injected advertisements into plaintext websites to earn extra revenue sending the web page over an encrypted connection stops them from being able to do that.
Authentication, it’s possible to encrypt data so that only someone with the paired private key can decrypt it, that way you know your message is only being read by the right person, similarly it is possible to sign messages with your encryption key to prove you are who you say you are. Classical cryptography like the ROT13 cypher (which rotated characters in the alphabet by thirteen characters) was more a way to encode data and operated under the principle of “security through obscurity”, the idea was to have a secret process to be able to read the message, this principle is flawed though as you only require one person to disclose the secret and all messages that ever used it can now be read by anyone.
Modern cryptography like the AES cypher operates under Kerkhoff’s principle which states: “A cryptosystem should remain secure if everything about the system, except the key, is public knowledge” this principle allows everyone to usee the same encryption system and only have to worry about keeping their encryption key secure.
Common Uses of Cryptography
- Cryptography was and still is a popular tool for keeping messages safe from prying eyes.
- I use cryptography to keep my messages secure.
- Cryptography includes things like cyphers.
Common Misuses of Cryptography
- I cryptograph my messages to keep them secure.
- Cryptography describes taking photos with hidden meanings