## Documentation ¶

### Overview ¶

Package xts implements the XTS cipher mode as specified in IEEE P1619/D16.

XTS mode is typically used for disk encryption, which presents a number of novel problems that make more common modes inapplicable. The disk is conceptually an array of sectors and we must be able to encrypt and decrypt a sector in isolation. However, an attacker must not be able to transpose two sectors of plaintext by transposing their ciphertext.

XTS wraps a block cipher with Rogaway's XEX mode in order to build a tweakable block cipher. This allows each sector to have a unique tweak and effectively create a unique key for each sector.

XTS does not provide any authentication. An attacker can manipulate the ciphertext and randomise a block (16 bytes) of the plaintext.

(Note: this package does not implement ciphertext-stealing so sectors must be a multiple of 16 bytes.)

### Index ¶

### Constants ¶

This section is empty.

### Variables ¶

This section is empty.

### Functions ¶

This section is empty.

### Types ¶

#### type Cipher ¶

```
type Cipher struct {
// contains filtered or unexported fields
}
```

Cipher contains an expanded key structure. It doesn't contain mutable state and therefore can be used concurrently.

#### func NewCipher ¶

NewCipher creates a Cipher given a function for creating the underlying block cipher (which must have a block size of 16 bytes). The key must be twice the length of the underlying cipher's key.

#### func (*Cipher) Decrypt ¶

Decrypt decrypts a sector of ciphertext and puts the result into plaintext. Plaintext and ciphertext may be the same slice but should not overlap. Sectors must be a multiple of 16 bytes and less than 2²⁴ bytes.