/// <summary>
/// Using the given lookup character array, reorders it using <see cref="DigestBasedRandomGenerator"/> with given parameters.
/// </summary>
/// <param name="chars">The lookup character array.</param>
/// <param name="seed">The seed material to <see cref="DigestBasedRandomGenerator"/>, as <see cref="Byte"/> array.</param>
/// <param name="algorithm">The <see cref="DigestAlgorithm"/> to use. If <c>null</c>, then <see cref="SHA512"/> will be used.</param>
/// <param name="seedCycleCount">How often the seed will be re-digested.</param>
/// <seealso cref="StringConversions.EncodeBinary(global::System.Byte[], global::System.Char[])"/>
/// <seealso cref="UtilPackExtensions.Shuffle{T}(T[], Random)"/>
public static void ShuffleBinaryEncodingCharactersFromSeed(
Char[] chars,
Byte[] seed,
DigestAlgorithm algorithm = null,
Int32 seedCycleCount = 10
)
{
using (var rng = new DigestBasedRandomGenerator(algorithm ?? new SHA512(), seedCycleCount: seedCycleCount, skipDisposeAlgorithm: false))
{
rng.AddSeedMaterial(seed);
using (var secRandom = new SecureRandom(rng))
{
chars.Shuffle(secRandom);
}
}
}
/// <summary>
/// This is convenience method to create new <see cref="DigestBasedRandomGenerator"/> and seed it with default, secure logic.
/// </summary>
/// <param name="algorithm">The algorithm that returned <see cref="DigestBasedRandomGenerator"/> should use.</param>
/// <param name="seedCycleCount">How often to re-seed the state of returned <see cref="DigestBasedRandomGenerator"/>.</param>
/// <param name="skipDisposeAlgorithm">Optional parameter controlling whether the <see cref="DigestBasedRandomGenerator"/> will, when disposed, dispose also the given <paramref name="algorithm"/>.</param>
/// <returns>A new instance of <see cref="DigestBasedRandomGenerator"/> with given parameters.</returns>
/// <exception cref="ArgumentNullException">If <paramref name="algorithm"/> is <c>null</c>.</exception>
public static DigestBasedRandomGenerator CreateAndSeedWithDefaultLogic(
BlockDigestAlgorithm algorithm,
Int32 seedCycleCount = DEFAULT_SEED_CYCLE_COUNT,
Boolean skipDisposeAlgorithm = false
)
{
var retVal = new DigestBasedRandomGenerator(algorithm, seedCycleCount, skipDisposeAlgorithm);
// Use Guid as random source (should be version 4)
retVal.AddSeedMaterial(Guid.NewGuid().ToByteArray());
// Use current ticks
retVal.AddSeedMaterial(DateTime.Now.Ticks);
// Use Guid again
retVal.AddSeedMaterial(Guid.NewGuid().ToByteArray());
return(retVal);
}
