added builder to KEMExtractSpec, minor JavaDoc in KEMGenerateSpec.

Author: dghgit

prov/src/main/java/org/bouncycastle/jcajce/spec/KEMExtractSpec.java

@@ -1,7 +1,6 @@
 package org.bouncycastle.jcajce.spec;
 
 import java.security.PrivateKey;
-import java.security.PublicKey;
 import java.security.spec.AlgorithmParameterSpec;
 
 import org.bouncycastle.asn1.nist.NISTObjectIdentifiers;
@@ -16,6 +15,87 @@ public class KEMExtractSpec
     private static final byte[] EMPTY_OTHER_INFO = new byte[0];
     private static AlgorithmIdentifier DefKdf = new AlgorithmIdentifier(X9ObjectIdentifiers.id_kdf_kdf3, new AlgorithmIdentifier(NISTObjectIdentifiers.id_sha256));
 
+    /**
+     * Builder class for creating a KEMExtractSpec.
+     */
+    public static final class Builder
+    {
+        private final PrivateKey privateKey;
+        private final byte[] encapsulation;
+        private final String algorithmName;
+        private final int keySizeInBits;
+
+        private AlgorithmIdentifier kdfAlgorithm;
+        private byte[] otherInfo;
+
+        /**
+         * Basic builder.
+         *
+         * @param privateKey       the private key to use for the secret extraction.
+         * @param encapsulation    the encapsulation to process.
+         * @param keyAlgorithmName the algorithm name for the secret key we want to generate.
+         * @param keySizeInBits    the size of the wrapping key we want to produce in bits.
+         */
+        public Builder(PrivateKey privateKey, byte[] encapsulation, String keyAlgorithmName, int keySizeInBits)
+        {
+            this.privateKey = privateKey;
+            this.encapsulation = Arrays.clone(encapsulation);
+            this.algorithmName = keyAlgorithmName;
+            this.keySizeInBits = keySizeInBits;
+            this.kdfAlgorithm = new AlgorithmIdentifier(X9ObjectIdentifiers.id_kdf_kdf3, new AlgorithmIdentifier(NISTObjectIdentifiers.id_sha256));
+            this.otherInfo = EMPTY_OTHER_INFO;
+        }
+
+        /**
+         * Use the shared secret directly for key wrap generation.
+         *
+         * @return the current Builder instance.
+         */
+        public Builder withNoKdf()
+        {
+            this.kdfAlgorithm = null;
+
+            return this;
+        }
+
+        /**
+         * Set the KDF algorithm and digest algorithm for wrap key generation. The default KDF is X9.44 KDF-3, also
+         * known as the NIST concatenation KDF.
+         *
+         * @param kdfAlgorithm the KDF algorithm to apply.
+         * @return the current Builder instance.
+         */
+        public Builder withKdfAlgorithm(AlgorithmIdentifier kdfAlgorithm)
+        {
+            this.kdfAlgorithm = kdfAlgorithm;
+
+            return this;
+        }
+
+        /**
+         * Set the OtherInfo to use with the KDF. The default OtherInfo is a zero length byte[].
+         *
+         * @param otherInfo the other info to use.
+         * @return the current Builder instance.
+         */
+        public Builder withOtherInfo(byte[] otherInfo)
+        {
+            this.otherInfo = (otherInfo == null) ? EMPTY_OTHER_INFO : Arrays.clone(otherInfo);
+
+            return this;
+        }
+
+        /**
+         * Build the new parameter spec.
+         *
+         * @return a new parameter spec configured according to the builder state.
+         */
+        public KEMExtractSpec build()
+        {
+            return new KEMExtractSpec(privateKey, encapsulation, algorithmName, keySizeInBits, kdfAlgorithm, otherInfo);
+        }
+    }
+
     private final PrivateKey privateKey;
     private final byte[] encapsulation;
 

prov/src/main/java/org/bouncycastle/jcajce/spec/KEMGenerateSpec.java

@@ -16,7 +16,7 @@ public class KEMGenerateSpec
     private static AlgorithmIdentifier DefKdf = new AlgorithmIdentifier(X9ObjectIdentifiers.id_kdf_kdf3, new AlgorithmIdentifier(NISTObjectIdentifiers.id_sha256));
 
     /**
-     * Builder class for creating a KTSParameterSpec.
+     * Builder class for creating a KEMGenerateSpec.
      */
     public static final class Builder
     {