Encryption software

Encryption software is software that can encrypt and decrypt data, often in the form of files on a hard drive or packets sent over a network.

Encryption software uses an encryption scheme that encodes computer data so that it cannot be recovered without the correct key. Software encryption is a fundamental part of modern computer communications and file protection.

The purpose of encryption is to prevent third parties from recovering any of the original data, or even any information about the data, from the encrypted data. This is particularly important for sensitive data like social security numbers.

Many encryption algorithms and schemes exist for many different purposes. Public-key algorithms like RSA and ElGamal are used by HTTPS for encrypting web communications and by PGP for encrypting emails. Symmetric-key algorithms like AES operated in CBC mode are popular for encrypting individual files. Full disk encryption has different constraints, and so the now-defunct TrueCrypt used AES in XTS mode.

Ciphers can be categorized into two general types: public key ciphers and symmetric key ciphers.

Public key systems use algorithms that rely on a pair of mathematically-linked keys. Data encrypted with one key can only be decrypted using the other key. These systems are used for exchanging secrets (often a key for subsequent use in a symmetric key cipher) and digital signatures.

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