Substitution Permuation Cipher
- Tags
- cryptography
Is a Composite Cipher that combines both a permutation and substitution to produce more secure ciphers. Many modern ciphers are implemented using multiple layers of this same system.
The need for substitution-permutation cipher ciphers arises from the fact that:
Ciphers based on either substitution or transposition are insecure.
The general advantage of composite ciphers is that:
| Term | Gives us | Description |
|---|---|---|
| Substitution | Confusion | Replaces some bits with other bits |
| Permutation | Diffusion | Spreads bits around to make it harder to follow them |