init commit

output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/CipherKeyGenerator.cs

@@ -0,0 +1,65 @@
+using System;
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Crypto;
+
+public class CipherKeyGenerator
+{
+	protected internal SecureRandom random;
+
+	protected internal int strength;
+
+	private bool uninitialised = true;
+
+	private int defaultStrength;
+
+	public int DefaultStrength => defaultStrength;
+
+	public CipherKeyGenerator()
+	{
+	}
+
+	internal CipherKeyGenerator(int defaultStrength)
+	{
+		if (defaultStrength < 1)
+		{
+			throw new ArgumentException("strength must be a positive value", "defaultStrength");
+		}
+		this.defaultStrength = defaultStrength;
+	}
+
+	public void Init(KeyGenerationParameters parameters)
+	{
+		if (parameters == null)
+		{
+			throw new ArgumentNullException("parameters");
+		}
+		uninitialised = false;
+		engineInit(parameters);
+	}
+
+	protected virtual void engineInit(KeyGenerationParameters parameters)
+	{
+		random = parameters.Random;
+		strength = (parameters.Strength + 7) / 8;
+	}
+
+	public byte[] GenerateKey()
+	{
+		if (uninitialised)
+		{
+			if (defaultStrength < 1)
+			{
+				throw new InvalidOperationException("Generator has not been initialised");
+			}
+			uninitialised = false;
+			engineInit(new KeyGenerationParameters(new SecureRandom(), defaultStrength));
+		}
+		return engineGenerateKey();
+	}
+
+	protected virtual byte[] engineGenerateKey()
+	{
+		return SecureRandom.GetNextBytes(random, strength);
+	}
+}