Encryption, with relation to cryptography, is the transformation of plaintext into ciphertext. Plaintext is any data or information that needs to be protected and the ciphertext is the encrypted information. This transformation is accomplished through the use of cryptographic cipher algorithms. Only those who have the “Key” can transform (decrypt) the ciphertext into plaintext which is why there are Key Handling mechanisms to keep the private key secret.
Encryption protects the privacy/confidentiality of the information but that is only part of the security that needs to be provided. There is also the need for authenticity and integrity and this can be provided by Authentication.
Encryption is done through the use of cipher algorithms, either symmetric (private-key) or asymmetric (public-key).
| Asymmetric (Public-Key) Ciphers | Symmetric (Private-Key) Ciphers | ||
|---|---|---|---|
| 64-bit Block Ciphers | 128-bit Block Ciphers | Stream Ciphers | |
| Rabin | DES | AES | RC4 |
| RSA | TDEA, 3DES, TDES | Camellia | SNOW2 |
| CAST-128 | CAST-256 | ||
| SEED | |||
| CCM* | |||
| ARIA | |||
| GCM* | |||
| NOTES: * CCM and GCM algorithms use an 128-bit block cipher to provide not only encryption but also authentication. | |||