1 files changed, 115 insertions, 0 deletions
diff --git a/crypto/src/pqc/asn1/KyberPrivateKey.cs b/crypto/src/pqc/asn1/KyberPrivateKey.cs
new file mode 100644
index 000000000..ee71e4f97
--- /dev/null
+++ b/crypto/src/pqc/asn1/KyberPrivateKey.cs
@@ -0,0 +1,115 @@
+using System;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Pqc.Asn1
+{
+    /**
+     *    Crystal Kyber Private Key Format.
+     *    See https://www.ietf.org/archive/id/draft-uni-qsckeys-kyber-00.html for details.
+     *    <pre>
+     *        KyberPrivateKey ::= SEQUENCE {
+     *        version     INTEGER {v0(0)}   -- version (round 3)
+     *        s           OCTET STRING,     -- EMPTY
+     *        hpk         OCTET STRING      -- EMPTY
+     *        nonce       OCTET STRING,     -- d
+     *        publicKey   [0] IMPLICIT KyberPublicKey OPTIONAL,
+     *                                      -- see next section
+     *        }
+     *    </pre>
+     */
+    public sealed class KyberPrivateKey
+        : Asn1Encodable
+    {
+        public static KyberPrivateKey GetInstance(object obj)
+        {
+            if (obj == null)
+                return null;
+            if (obj is KyberPrivateKey kyberPublicKey)
+                return kyberPublicKey;
+            return new KyberPrivateKey(Asn1Sequence.GetInstance(obj));
+        }
+
+        public static KyberPrivateKey GetInstance(Asn1TaggedObject taggedObject, bool declaredExplicit)
+        {
+            return GetInstance(Asn1Sequence.GetInstance(taggedObject, declaredExplicit));
+        }
+
+        private int version;
+        private byte[] s;
+#pragma warning disable CS0618 // Type or member is obsolete
+        private KyberPublicKey publicKey;
+#pragma warning restore CS0618 // Type or member is obsolete
+        private byte[] hpk;
+        private byte[] nonce;
+
+#pragma warning disable CS0618 // Type or member is obsolete
+        public KyberPrivateKey(int version, byte[] s, byte[] hpk, byte[] nonce, KyberPublicKey publicKey)
+        {
+            this.version = version;
+            this.s = s;
+            this.publicKey = publicKey;
+            this.hpk = hpk;
+            this.nonce = nonce;
+        }
+#pragma warning restore CS0618 // Type or member is obsolete
+
+        public KyberPrivateKey(int version, byte[] s, byte[] hpk, byte[] nonce)
+            : this(version, s, hpk, nonce, null)
+        {
+        }
+
+        private KyberPrivateKey(Asn1Sequence seq)
+        {
+            version = DerInteger.GetInstance(seq[0]).IntValueExact;
+            if (version != 0)
+                throw new ArgumentException("unrecognized version");
+
+            s = Arrays.Clone(Asn1OctetString.GetInstance(seq[1]).GetOctets());
+
+            int skipPubKey = 1;
+            if (seq.Count == 5)
+            {
+                skipPubKey = 0;
+#pragma warning disable CS0618 // Type or member is obsolete
+                publicKey = KyberPublicKey.GetInstance(seq[2]);
+#pragma warning restore CS0618 // Type or member is obsolete
+            }
+
+            hpk = Arrays.Clone(Asn1OctetString.GetInstance(seq[3 - skipPubKey]).GetOctets());
+
+            nonce = Arrays.Clone(Asn1OctetString.GetInstance(seq[4 - skipPubKey]).GetOctets());
+        }
+
+        public int Version => version;
+
+        public byte[] GetS() => Arrays.Clone(s);
+
+#pragma warning disable CS0618 // Type or member is obsolete
+        public KyberPublicKey PublicKey => publicKey;
+#pragma warning restore CS0618 // Type or member is obsolete
+
+        public byte[] GetHpk() => Arrays.Clone(hpk);
+
+        public byte[] GetNonce() => Arrays.Clone(nonce);
+
+        public override Asn1Object ToAsn1Object()
+        {
+            Asn1EncodableVector v = new Asn1EncodableVector(5);
+
+            v.Add(new DerInteger(version));
+            v.Add(new DerOctetString(s));
+            if (publicKey != null)
+            {
+#pragma warning disable CS0618 // Type or member is obsolete
+                v.Add(new KyberPublicKey(publicKey.T, publicKey.Rho));
+#pragma warning restore CS0618 // Type or member is obsolete
+            }
+            v.Add(new DerOctetString(hpk));
+            v.Add(new DerOctetString(nonce));
+
+            return new DerSequence(v);
+        }
+    }
+}