Struct rand_isaac::isaac64::Isaac64Rng [−][src]
A random number generator that uses ISAAC-64, the 64-bit variant of the ISAAC algorithm.
ISAAC stands for “Indirection, Shift, Accumulate, Add, and Count” which are the principal bitwise operations employed. It is the most advanced of a series of array based random number generator designed by Robert Jenkins in 19961.
ISAAC-64 is mostly similar to ISAAC. Because it operates on 64-bit integers instead of 32-bit, it uses twice as much memory to hold its state and results. Also it uses different constants for shifts and indirect indexing, optimized to give good results for 64bit arithmetic.
ISAAC-64 is notably fast and produces excellent quality random numbers for non-cryptographic applications.
In spite of being designed with cryptographic security in mind, ISAAC hasn’t
been stringently cryptanalyzed and thus cryptographers do not not
consensually trust it to be secure. When looking for a secure RNG, prefer
Hc128Rng
instead, which, like ISAAC, is an array-based RNG and one of
the stream-ciphers selected the by eSTREAM contest.
Overview of the ISAAC-64 algorithm:
(in pseudo-code)
Input: a, b, c, s[256] // state
Output: r[256] // results
mix(a,i) = !(a ^ a << 21) if i = 0 mod 4
a ^ a >> 5 if i = 1 mod 4
a ^ a << 12 if i = 2 mod 4
a ^ a >> 33 if i = 3 mod 4
c = c + 1
b = b + c
for i in 0..256 {
x = s_[i]
a = mix(a,i) + s[i+128 mod 256]
y = a + b + s[x>>3 mod 256]
s[i] = y
b = x + s[y>>11 mod 256]
r[i] = b
}
This implementation uses BlockRng64
to implement the RngCore
methods.
See for more information the documentation of IsaacRng
.
Bob Jenkins, ISAAC and RC4 ↩
Implementations
impl Isaac64Rng
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pub fn new_from_u64(seed: u64) -> Self
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use SeedableRng::seed_from_u64 instead
Create an ISAAC-64 random number generator using an u64
as seed.
If seed == 0
this will produce the same stream of random numbers as
the reference implementation when used unseeded.
Trait Implementations
impl Clone for Isaac64Rng
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impl Debug for Isaac64Rng
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impl RngCore for Isaac64Rng
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impl SeedableRng for Isaac64Rng
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Auto Trait Implementations
impl RefUnwindSafe for Isaac64Rng
impl Send for Isaac64Rng
impl Sync for Isaac64Rng
impl Unpin for Isaac64Rng
impl UnwindSafe for Isaac64Rng
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,