# [−][src]Struct rand_hc::Hc128Rng

    pub struct Hc128Rng(_);

A cryptographically secure random number generator that uses the HC-128 algorithm.

HC-128 is a stream cipher designed by Hongjun Wu1, that we use as an RNG. It is selected as one of the "stream ciphers suitable for widespread adoption" by eSTREAM2.

HC-128 is an array based RNG. In this it is similar to RC-4 and ISAAC before it, but those have never been proven cryptographically secure (or have even been significantly compromised, as in the case of RC-43).

Because HC-128 works with simple indexing into a large array and with a few operations that parallelize well, it has very good performance. The size of the array it needs, 4kb, can however be a disadvantage.

This implementation is not based on the version of HC-128 submitted to the eSTREAM contest, but on a later version by the author with a few small improvements from December 15, 20094.

HC-128 has no known weaknesses that are easier to exploit than doing a brute-force search of 2128. A very comprehensive analysis of the current state of known attacks / weaknesses of HC-128 is given in Some Results On Analysis And Implementation Of HC-128 Stream Cipher5.

The average cycle length is expected to be 21024*32+10-1 = 232777. We support seeding with a 256-bit array, which matches the 128-bit key concatenated with a 128-bit IV from the stream cipher.

This implementation uses an output buffer of sixteen `u32` words, and uses `BlockRng` to implement the `RngCore` methods.

## References

1. Hongjun Wu (2008). "The Stream Cipher HC-128". The eSTREAM Finalists, LNCS 4986, pp. 39–47, Springer-Verlag. ↩

2. eSTREAM: the ECRYPT Stream Cipher Project ↩

3. Internet Engineering Task Force (February 2015), "Prohibiting RC4 Cipher Suites". ↩

4. Hongjun Wu, Stream Ciphers HC-128 and HC-256 ↩

5. Shashwat Raizada (January 2015),"Some Results On Analysis And Implementation Of HC-128 Stream Cipher". ↩

## Trait Implementations

### `impl Debug for Hc128Rng`[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`[src]

Formats the value using the given formatter. Read more

### `impl Clone for Hc128Rng`[src]

#### `fn clone(&self) -> Hc128Rng`[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`1.0.0[src]

Performs copy-assignment from `source`. Read more

### `impl SeedableRng for Hc128Rng`[src]

#### `type Seed = <Hc128Core as SeedableRng>::Seed`

Seed type, which is restricted to types mutably-dereferencable as `u8` arrays (we recommend `[u8; N]` for some `N`). Read more

#### `fn from_seed(seed: Self::Seed) -> Self`[src]

Create a new PRNG using the given seed. Read more

#### `fn from_rng<R: RngCore>(rng: R) -> Result<Self, Error>`[src]

Create a new PRNG seeded from another `Rng`. Read more

#### `fn seed_from_u64(state: u64) -> Self`[src]

Create a new PRNG using a `u64` seed. Read more

### `impl RngCore for Hc128Rng`[src]

#### `fn next_u32(&mut self) -> u32`[src]

Return the next random `u32`. Read more

#### `fn next_u64(&mut self) -> u64`[src]

Return the next random `u64`. Read more

#### `fn fill_bytes(&mut self, dest: &mut [u8])`[src]

Fill `dest` with random data. Read more

#### `fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>`[src]

Fill `dest` entirely with random data. Read more

### `impl CryptoRng for Hc128Rng`[src]

## Auto Trait Implementations

### `impl Unpin for Hc128Rng`

### `impl Send for Hc128Rng`

### `impl Sync for Hc128Rng`

### `impl UnwindSafe for Hc128Rng`

### `impl RefUnwindSafe for Hc128Rng`

## Blanket Implementations

### `impl<T> From<T> for T`[src]

#### `fn from(t: T) -> T`[src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `fn into(self) -> U`[src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>`[src]

Performs the conversion.

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `fn borrow(&self) -> &T`[src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `fn borrow_mut(&mut self) -> &mut T`[src]

Mutably borrows from an owned value. Read more

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `fn type_id(&self) -> TypeId`[src]

Gets the `TypeId` of `self`. Read more

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `fn to_owned(&self) -> T`[src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `fn clone_into(&self, target: &mut T)`[src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into`)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

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