Cryptography
- It is science concerned with the study of secret communication
- Encryption
- Process of transforming data such that only authorized people can decrypt it
- Encoding
- Transforming data that anybody can decode
- Decryption
- Process of transforming encrypted data back to original data
- Cipher
- aka Cypher
- Algorithm for performing encryption/decryption
- Cryptanalysis
- Study of methods for obtaining the meaning of encrypted information without access to the key
Types of Crypto systems
- Symmetric
- Shared secret key for both signing and verification
- Generally simple and fast
- Examples
- HMAC SHA256
- Blowfish
- AES (Advanced Encryption Standard)
- Asymmetric
- Uses pubic/private key pairs
- Private key signs the token
- Public key verifies the token
- Generally slow
- Examples:
- RSA (PKCS#1)
- Diffie–Hellman key exchange
- Digital Signature
- Example protocols
- GPG
- SSH
- SSL/TLS
- IPSec
- Bitcoin