diff --git a/crypto/src/crypto/parameters/HKDFParameters.cs b/crypto/src/crypto/parameters/HKDFParameters.cs
new file mode 100644
index 000000000..6d1465e4c
--- /dev/null
+++ b/crypto/src/crypto/parameters/HKDFParameters.cs
@@ -0,0 +1,119 @@
+using System;
+
+using Org.BouncyCastle.Crypto.Macs;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Parameters
+{
+ /**
+ * Parameter class for the HkdfBytesGenerator class.
+ */
+ public class HkdfParameters
+ : IDerivationParameters
+ {
+ private readonly byte[] ikm;
+ private readonly bool skipExpand;
+ private readonly byte[] salt;
+ private readonly byte[] info;
+
+ private HkdfParameters(byte[] ikm, bool skip, byte[] salt, byte[] info)
+ {
+ if (ikm == null)
+ throw new ArgumentNullException("ikm");
+
+ this.ikm = Arrays.Clone(ikm);
+ this.skipExpand = skip;
+
+ if (salt == null || salt.Length == 0)
+ {
+ this.salt = null;
+ }
+ else
+ {
+ this.salt = Arrays.Clone(salt);
+ }
+
+ if (info == null)
+ {
+ this.info = new byte[0];
+ }
+ else
+ {
+ this.info = Arrays.Clone(info);
+ }
+ }
+
+ /**
+ * Generates parameters for HKDF, specifying both the optional salt and
+ * optional info. Step 1: Extract won't be skipped.
+ *
+ * @param ikm the input keying material or seed
+ * @param salt the salt to use, may be null for a salt for hashLen zeros
+ * @param info the info to use, may be null for an info field of zero bytes
+ */
+ public HkdfParameters(byte[] ikm, byte[] salt, byte[] info)
+ : this(ikm, false, salt, info)
+ {
+ }
+
+ /**
+ * Factory method that makes the HKDF skip the extract part of the key
+ * derivation function.
+ *
+ * @param ikm the input keying material or seed, directly used for step 2:
+ * Expand
+ * @param info the info to use, may be null for an info field of zero bytes
+ * @return HKDFParameters that makes the implementation skip step 1
+ */
+ public static HkdfParameters SkipExtractParameters(byte[] ikm, byte[] info)
+ {
+ return new HkdfParameters(ikm, true, null, info);
+ }
+
+ public static HkdfParameters DefaultParameters(byte[] ikm)
+ {
+ return new HkdfParameters(ikm, false, null, null);
+ }
+
+ /**
+ * Returns the input keying material or seed.
+ *
+ * @return the keying material
+ */
+ public virtual byte[] GetIkm()
+ {
+ return Arrays.Clone(ikm);
+ }
+
+ /**
+ * Returns if step 1: extract has to be skipped or not
+ *
+ * @return true for skipping, false for no skipping of step 1
+ */
+ public virtual bool SkipExtract
+ {
+ get { return skipExpand; }
+ }
+
+ /**
+ * Returns the salt, or null if the salt should be generated as a byte array
+ * of HashLen zeros.
+ *
+ * @return the salt, or null
+ */
+ public virtual byte[] GetSalt()
+ {
+ return Arrays.Clone(salt);
+ }
+
+ /**
+ * Returns the info field, which may be empty (null is converted to empty).
+ *
+ * @return the info field, never null
+ */
+ public virtual byte[] GetInfo()
+ {
+ return Arrays.Clone(info);
+ }
+ }
+}
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