Class Primes

Namespace

Org.BouncyCastle.Math

Assembly

BouncyCastle.Cryptography.dll

Utility methods for generating primes and testing for primality.

public static class Primes

Inheritance

object

Primes

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Fields

SmallFactorLimit

public static readonly int SmallFactorLimit

Field Value

int

Methods

EnhancedMRProbablePrimeTest(BigInteger, SecureRandom, int)

FIPS 186-4 C.3.2 Enhanced Miller-Rabin Probabilistic Primality Test.

public static Primes.MROutput EnhancedMRProbablePrimeTest(BigInteger candidate, SecureRandom random, int iterations)

Parameters

candidate BigInteger

The BigInteger instance to test for primality.

random SecureRandom

The source of randomness to use to choose bases.

iterations int

The number of randomly-chosen bases to perform the test for.

Returns

Primes.MROutput

An Primes.MROutput instance that can be further queried for details.

Remarks

Run several iterations of the Miller-Rabin algorithm with randomly-chosen bases. This is an alternative to IsMRProbablePrime(BigInteger, SecureRandom, int) that provides more information about a composite candidate, which may be useful when generating or validating RSA moduli.

GenerateSTRandomPrime(IDigest, int, byte[])

FIPS 186-4 C.6 Shawe-Taylor Random_Prime Routine.

public static Primes.STOutput GenerateSTRandomPrime(IDigest hash, int length, byte[] inputSeed)

Parameters

hash IDigest

The IDigest instance to use (as "Hash()"). Cannot be null.

length int

The length (in bits) of the prime to be generated. Must be at least 2.

inputSeed byte[]

The seed to be used for the generation of the requested prime. Cannot be null or empty.

Returns

Primes.STOutput

An Primes.STOutput instance containing the requested prime.

Remarks

Construct a provable prime number using a hash function.

HasAnySmallFactors(BigInteger)

A fast check for small divisors, up to some implementation-specific limit.

public static bool HasAnySmallFactors(BigInteger candidate)

Parameters

candidate BigInteger

The BigInteger instance to test for division by small factors.

Returns

bool

true if the candidate is found to have any small factors, false otherwise.

IsMRProbablePrime(BigInteger, SecureRandom, int)

FIPS 186-4 C.3.1 Miller-Rabin Probabilistic Primality Test.

public static bool IsMRProbablePrime(BigInteger candidate, SecureRandom random, int iterations)

Parameters

candidate BigInteger

The BigInteger instance to test for primality.

random SecureRandom

The source of randomness to use to choose bases.

iterations int

The number of randomly-chosen bases to perform the test for.

Returns

bool

false if any witness to compositeness is found amongst the chosen bases (so candidate is definitely NOT prime), or else true (indicating primality with some probability dependent on the number of iterations that were performed).

Remarks

Run several iterations of the Miller-Rabin algorithm with randomly-chosen bases.

IsMRProbablePrimeToBase(BigInteger, BigInteger)

FIPS 186-4 C.3.1 Miller-Rabin Probabilistic Primality Test (to a fixed base).

public static bool IsMRProbablePrimeToBase(BigInteger candidate, BigInteger baseValue)

Parameters

candidate BigInteger

The BigInteger instance to test for primality.

baseValue BigInteger

The base value to use for this iteration.

Returns

bool

false if baseValue is a witness to compositeness (so candidate is definitely NOT prime), or else true.

Remarks

Run a single iteration of the Miller-Rabin algorithm against the specified base.