Symmetric Cryptography
Abstract
Oldest form of cryptography, use of a cypher (secret key), which converts plain text to cypher-text. Same key is used to encrypt and decrypt.
Pros:
- Very Fast - Good for Bulk Encryption
Cons:
- Either not as secure, or not as practical.
- If you transmit the key - Someone can intercept the key and then decrypt
- If you don’t transmit the key - You are unable to encrypt data to new receivers, or dynamic/larger receivers, i.e. Amazon, Facebook
Examples:
Advanced Encryption Standard (AES) - completely secure as far as we understand.
Asymmetric (Public Key) Cryptography
Abstract:
A message is encrypted with a public key, and then only the private key can decrypt it. Solves the key distribution problem. Requires the Private Key to be secure
Pros:
- Incredibly secure provided used correctly
- Keys distribution problem solved
Cons:
- Immensely Slow To Decrypt
- Phenomenally difficult to implement incorrectly (RSA for example)
Examples:
RSA Diffie-Hellman Ephemeral Elliptical Curve Diffie-Hellman
Hybrid Cryptography
Abstract
In essence, usage of Asymmetric Encryption to encrypt a Symmetric key that encrypts the rest of the data.
This solves the problem of key distribution of Symmetric keys, while also maintaining the general speed of Symmetric Encryption