Refactoring: reduced allocations

16 files changed, 162 insertions, 42 deletions

diff --git a/crypto/src/asn1/x509/SubjectPublicKeyInfo.cs b/crypto/src/asn1/x509/SubjectPublicKeyInfo.cs
index 4875152eb..234990fc7 100644
--- a/crypto/src/asn1/x509/SubjectPublicKeyInfo.cs
+++ b/crypto/src/asn1/x509/SubjectPublicKeyInfo.cs
@@ -49,7 +49,15 @@ namespace Org.BouncyCastle.Asn1.X509
             this.algID = algID;
         }
 
-		private SubjectPublicKeyInfo(
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        public SubjectPublicKeyInfo(AlgorithmIdentifier algID, ReadOnlySpan<byte> publicKey)
+        {
+            this.keyData = new DerBitString(publicKey);
+            this.algID = algID;
+        }
+#endif
+
+        private SubjectPublicKeyInfo(
             Asn1Sequence seq)
         {
 			if (seq.Count != 2)
diff --git a/crypto/src/crypto/fpe/FpeFf3_1Engine.cs b/crypto/src/crypto/fpe/FpeFf3_1Engine.cs
index bc8d22fae..5e8148bb8 100644
--- a/crypto/src/crypto/fpe/FpeFf3_1Engine.cs
+++ b/crypto/src/crypto/fpe/FpeFf3_1Engine.cs
@@ -19,9 +19,7 @@ namespace Org.BouncyCastle.Crypto.Fpe
             : base(baseCipher)
         {
             if (IsOverrideSet(SP80038G.FPE_DISABLED))
-            {
                 throw new InvalidOperationException("FPE disabled");
-            }
         }
 
         public override void Init(bool forEncryption, ICipherParameters parameters)
@@ -29,7 +27,7 @@ namespace Org.BouncyCastle.Crypto.Fpe
             this.forEncryption = forEncryption;
             this.fpeParameters = (FpeParameters)parameters;
 
-            baseCipher.Init(!fpeParameters.UseInverseFunction, ReverseKey(fpeParameters.Key));
+            baseCipher.Init(!fpeParameters.UseInverseFunction, fpeParameters.Key.Reverse());
 
             if (fpeParameters.GetTweak().Length != 7)
                 throw new ArgumentException("tweak should be 56 bits");
@@ -82,18 +80,5 @@ namespace Org.BouncyCastle.Crypto.Fpe
 
             return length;
         }
-
-        private static KeyParameter ReverseKey(KeyParameter key)
-        {
-#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
-            return KeyParameter.Create(key.KeyLength, key, (bytes, key) =>
-            {
-                key.Key.CopyTo(bytes);
-                bytes.Reverse();
-            });
-#else
-            return new KeyParameter(Arrays.Reverse(key.GetKey()));
-#endif
-        }
     }
 }
diff --git a/crypto/src/crypto/fpe/SP80038G.cs b/crypto/src/crypto/fpe/SP80038G.cs
index c57a34762..5488f20fd 100644
--- a/crypto/src/crypto/fpe/SP80038G.cs
+++ b/crypto/src/crypto/fpe/SP80038G.cs
@@ -358,11 +358,10 @@ namespace Org.BouncyCastle.Crypto.Fpe
             // iii.
             Array.Reverse(P);
             cipher.ProcessBlock(P, 0, P, 0);
-            Array.Reverse(P);
             byte[] S = P;
 
             // iv.
-            return new BigInteger(1, S);
+            return new BigInteger(1, S, bigEndian: false);
         }
 
         private static void CheckArgs(IBlockCipher cipher, bool isFF1, int radix, ushort[] buf, int off, int len)
diff --git a/crypto/src/crypto/parameters/Ed25519PrivateKeyParameters.cs b/crypto/src/crypto/parameters/Ed25519PrivateKeyParameters.cs
index 6d2e44937..3a760afc1 100644
--- a/crypto/src/crypto/parameters/Ed25519PrivateKeyParameters.cs
+++ b/crypto/src/crypto/parameters/Ed25519PrivateKeyParameters.cs
@@ -70,6 +70,12 @@ namespace Org.BouncyCastle.Crypto.Parameters
             return Arrays.Clone(data);
         }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        internal ReadOnlySpan<byte> DataSpan => data;
+
+        internal ReadOnlyMemory<byte> DataMemory => data;
+#endif
+
         public Ed25519PublicKeyParameters GeneratePublicKey()
         {
             lock (data)
diff --git a/crypto/src/crypto/parameters/Ed448PrivateKeyParameters.cs b/crypto/src/crypto/parameters/Ed448PrivateKeyParameters.cs
index a9d1d0e93..544dbf32d 100644
--- a/crypto/src/crypto/parameters/Ed448PrivateKeyParameters.cs
+++ b/crypto/src/crypto/parameters/Ed448PrivateKeyParameters.cs
@@ -70,6 +70,12 @@ namespace Org.BouncyCastle.Crypto.Parameters
             return Arrays.Clone(data);
         }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        internal ReadOnlySpan<byte> DataSpan => data;
+
+        internal ReadOnlyMemory<byte> DataMemory => data;
+#endif
+
         public Ed448PublicKeyParameters GeneratePublicKey()
         {
             lock (data)
diff --git a/crypto/src/crypto/parameters/KeyParameter.cs b/crypto/src/crypto/parameters/KeyParameter.cs
index bd2482f22..c29dfe61b 100644
--- a/crypto/src/crypto/parameters/KeyParameter.cs
+++ b/crypto/src/crypto/parameters/KeyParameter.cs
@@ -85,5 +85,12 @@ namespace Org.BouncyCastle.Crypto.Parameters
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
         internal ReadOnlySpan<byte> Key => m_key;
 #endif
+
+        internal KeyParameter Reverse()
+        {
+            var reversed = new KeyParameter(m_key.Length);
+            Arrays.Reverse(m_key, reversed.m_key);
+            return reversed;
+        }
     }
 }
diff --git a/crypto/src/crypto/parameters/X25519PrivateKeyParameters.cs b/crypto/src/crypto/parameters/X25519PrivateKeyParameters.cs
index 8b263c861..ca989a8d3 100644
--- a/crypto/src/crypto/parameters/X25519PrivateKeyParameters.cs
+++ b/crypto/src/crypto/parameters/X25519PrivateKeyParameters.cs
@@ -68,6 +68,12 @@ namespace Org.BouncyCastle.Crypto.Parameters
             return Arrays.Clone(data);
         }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        internal ReadOnlySpan<byte> DataSpan => data;
+
+        internal ReadOnlyMemory<byte> DataMemory => data;
+#endif
+
         public X25519PublicKeyParameters GeneratePublicKey()
         {
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
diff --git a/crypto/src/crypto/parameters/X25519PublicKeyParameters.cs b/crypto/src/crypto/parameters/X25519PublicKeyParameters.cs
index 5d94ac10a..c68be3060 100644
--- a/crypto/src/crypto/parameters/X25519PublicKeyParameters.cs
+++ b/crypto/src/crypto/parameters/X25519PublicKeyParameters.cs
@@ -60,6 +60,12 @@ namespace Org.BouncyCastle.Crypto.Parameters
             return Arrays.Clone(data);
         }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        internal ReadOnlySpan<byte> DataSpan => data;
+
+        internal ReadOnlyMemory<byte> DataMemory => data;
+#endif
+
         private static byte[] Validate(byte[] buf)
         {
             if (buf.Length != KeySize)
diff --git a/crypto/src/crypto/parameters/X448PrivateKeyParameters.cs b/crypto/src/crypto/parameters/X448PrivateKeyParameters.cs
index 555773b10..712885875 100644
--- a/crypto/src/crypto/parameters/X448PrivateKeyParameters.cs
+++ b/crypto/src/crypto/parameters/X448PrivateKeyParameters.cs
@@ -68,6 +68,12 @@ namespace Org.BouncyCastle.Crypto.Parameters
             return Arrays.Clone(data);
         }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        internal ReadOnlySpan<byte> DataSpan => data;
+
+        internal ReadOnlyMemory<byte> DataMemory => data;
+#endif
+
         public X448PublicKeyParameters GeneratePublicKey()
         {
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
diff --git a/crypto/src/crypto/parameters/X448PublicKeyParameters.cs b/crypto/src/crypto/parameters/X448PublicKeyParameters.cs
index 94db22147..e66056f9c 100644
--- a/crypto/src/crypto/parameters/X448PublicKeyParameters.cs
+++ b/crypto/src/crypto/parameters/X448PublicKeyParameters.cs
@@ -60,6 +60,12 @@ namespace Org.BouncyCastle.Crypto.Parameters
             return Arrays.Clone(data);
         }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        internal ReadOnlySpan<byte> DataSpan => data;
+
+        internal ReadOnlyMemory<byte> DataMemory => data;
+#endif
+
         private static byte[] Validate(byte[] buf)
         {
             if (buf.Length != KeySize)
diff --git a/crypto/src/openpgp/PgpEncryptedDataGenerator.cs b/crypto/src/openpgp/PgpEncryptedDataGenerator.cs
index a6482db6c..ac847ddb6 100644
--- a/crypto/src/openpgp/PgpEncryptedDataGenerator.cs
+++ b/crypto/src/openpgp/PgpEncryptedDataGenerator.cs
@@ -149,9 +149,14 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
                     byte[] secret = new byte[agreement.AgreementSize];
                     agreement.CalculateAgreement(cryptoPublicKey, secret, 0);
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                    Span<byte> ephPubEncoding = stackalloc byte[1 + X25519PublicKeyParameters.KeySize];
+                    ((X25519PublicKeyParameters)ephKp.Public).Encode(ephPubEncoding[1..]);
+#else
                     byte[] ephPubEncoding = new byte[1 + X25519PublicKeyParameters.KeySize];
-                    ephPubEncoding[0] = 0x40;
                     ((X25519PublicKeyParameters)ephKp.Public).Encode(ephPubEncoding, 1);
+#endif
+                    ephPubEncoding[0] = 0x40;
 
                     return EncryptSessionInfo(ecPubKey, sessionInfo, secret, ephPubEncoding, random);
                 }
@@ -168,9 +173,14 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
                     byte[] secret = new byte[agreement.AgreementSize];
                     agreement.CalculateAgreement(cryptoPublicKey, secret, 0);
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                    Span<byte> ephPubEncoding = stackalloc byte[1 + X448PublicKeyParameters.KeySize];
+                    ((X448PublicKeyParameters)ephKp.Public).Encode(ephPubEncoding[1..]);
+#else
                     byte[] ephPubEncoding = new byte[1 + X448PublicKeyParameters.KeySize];
-                    ephPubEncoding[0] = 0x40;
                     ((X448PublicKeyParameters)ephKp.Public).Encode(ephPubEncoding, 1);
+#endif
+                    ephPubEncoding[0] = 0x40;
 
                     return EncryptSessionInfo(ecPubKey, sessionInfo, secret, ephPubEncoding, random);
                 }
@@ -188,13 +198,29 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
                     BigInteger S = agreement.CalculateAgreement(cryptoPublicKey);
                     byte[] secret = BigIntegers.AsUnsignedByteArray(agreement.GetFieldSize(), S);
 
-                    byte[] ephPubEncoding = ((ECPublicKeyParameters)ephKp.Public).Q.GetEncoded(false);
+                    var q = ((ECPublicKeyParameters)ephKp.Public).Q;
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                    int encodedLength = q.GetEncodedLength(false);
+                    Span<byte> ephPubEncoding = encodedLength <= 512
+                        ? stackalloc byte[encodedLength]
+                        : new byte[encodedLength];
+                    q.EncodeTo(false, ephPubEncoding);
+#else
+                    byte[] ephPubEncoding = q.GetEncoded(false);
+#endif
+
                     return EncryptSessionInfo(ecPubKey, sessionInfo, secret, ephPubEncoding, random);
                 }
             }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+            private byte[] EncryptSessionInfo(ECDHPublicBcpgKey ecPubKey, byte[] sessionInfo, byte[] secret,
+                ReadOnlySpan<byte> ephPubEncoding, SecureRandom random)
+#else
             private byte[] EncryptSessionInfo(ECDHPublicBcpgKey ecPubKey, byte[] sessionInfo, byte[] secret,
                 byte[] ephPubEncoding, SecureRandom random)
+#endif
             {
                 var key = new KeyParameter(Rfc6637Utilities.CreateKey(pubKey.PublicKeyPacket, secret));
 
@@ -402,14 +428,12 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
             sessionInfo[sessionInfo.Length - 1] = (byte)(check);
         }
 
-		private byte[] CreateSessionInfo(
-			SymmetricKeyAlgorithmTag	algorithm,
-			KeyParameter				key)
+		private byte[] CreateSessionInfo(SymmetricKeyAlgorithmTag algorithm, KeyParameter key)
 		{
-			byte[] keyBytes = key.GetKey();
-			byte[] sessionInfo = new byte[keyBytes.Length + 3];
-			sessionInfo[0] = (byte) algorithm;
-			keyBytes.CopyTo(sessionInfo, 1);
+            int keyLength = key.KeyLength;
+			byte[] sessionInfo = new byte[keyLength + 3];
+			sessionInfo[0] = (byte)algorithm;
+            key.CopyTo(sessionInfo, 1, keyLength);
 			AddCheckSum(sessionInfo);
 			return sessionInfo;
 		}
diff --git a/crypto/src/openpgp/PgpPublicKey.cs b/crypto/src/openpgp/PgpPublicKey.cs
index 8b3575909..fa924ff37 100644
--- a/crypto/src/openpgp/PgpPublicKey.cs
+++ b/crypto/src/openpgp/PgpPublicKey.cs
@@ -575,8 +575,11 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
 
                         return PublicKeyFactory.CreateKey(new SubjectPublicKeyInfo(
                             new AlgorithmIdentifier(curveOid),
-                            // TODO Span variant
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                            pEnc.AsSpan(1)));
+#else
                             Arrays.CopyOfRange(pEnc, 1, pEnc.Length)));
+#endif
                     }
                     else if (EdECObjectIdentifiers.id_X448.Equals(curveOid))
                     {
@@ -586,8 +589,11 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
 
                         return PublicKeyFactory.CreateKey(new SubjectPublicKeyInfo(
                             new AlgorithmIdentifier(curveOid),
-                            // TODO Span variant
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                            pEnc.AsSpan(1)));
+#else
                             Arrays.CopyOfRange(pEnc, 1, pEnc.Length)));
+#endif
                     }
                     else
                     {
@@ -608,8 +614,11 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
 
                         return PublicKeyFactory.CreateKey(new SubjectPublicKeyInfo(
                             new AlgorithmIdentifier(curveOid),
-                            // TODO Span variant
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                            pEnc.AsSpan(1)));
+#else
                             Arrays.CopyOfRange(pEnc, 1, pEnc.Length)));
+#endif
                     }
                     else if (EdECObjectIdentifiers.id_Ed448.Equals(curveOid))
                     {
@@ -619,8 +628,11 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
 
                         return PublicKeyFactory.CreateKey(new SubjectPublicKeyInfo(
                             new AlgorithmIdentifier(curveOid),
-                            // TODO Span variant
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                            pEnc.AsSpan(1)));
+#else
                             Arrays.CopyOfRange(pEnc, 1, pEnc.Length)));
+#endif
                     }
                     else 
                     {
diff --git a/crypto/src/openpgp/PgpSecretKey.cs b/crypto/src/openpgp/PgpSecretKey.cs
index 627b6788a..184621b5c 100644
--- a/crypto/src/openpgp/PgpSecretKey.cs
+++ b/crypto/src/openpgp/PgpSecretKey.cs
@@ -67,9 +67,13 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
                     }
                     else
                     {
-                        // 'reverse' because the native format for X25519 private keys is little-endian
+                        // The native format for X25519 private keys is little-endian
                         X25519PrivateKeyParameters xK = (X25519PrivateKeyParameters)privKey.Key;
-                        secKey = new ECSecretBcpgKey(new BigInteger(1, Arrays.ReverseInPlace(xK.GetEncoded())));
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                        secKey = new ECSecretBcpgKey(new BigInteger(1, xK.DataSpan, bigEndian: false));
+#else
+                        secKey = new ECSecretBcpgKey(new BigInteger(1, xK.GetEncoded(), bigEndian: false));
+#endif
                     }
                     break;
                 }
@@ -81,11 +85,19 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
                 {
                     if (privKey.Key is Ed25519PrivateKeyParameters ed25519K)
                     {
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                        secKey = new EdSecretBcpgKey(new BigInteger(1, ed25519K.DataSpan));
+#else
                         secKey = new EdSecretBcpgKey(new BigInteger(1, ed25519K.GetEncoded()));
+#endif
                     }
                     else if (privKey.Key is Ed448PrivateKeyParameters ed448K)
                     {
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                        secKey = new EdSecretBcpgKey(new BigInteger(1, ed448K.DataSpan));
+#else
                         secKey = new EdSecretBcpgKey(new BigInteger(1, ed448K.GetEncoded()));
+#endif
                     }
                     else
                     {
diff --git a/crypto/src/pkcs/PrivateKeyInfoFactory.cs b/crypto/src/pkcs/PrivateKeyInfoFactory.cs
index d56831f35..1bfeedb79 100644
--- a/crypto/src/pkcs/PrivateKeyInfoFactory.cs
+++ b/crypto/src/pkcs/PrivateKeyInfoFactory.cs
@@ -112,18 +112,28 @@ namespace Org.BouncyCastle.Pkcs
                 return new PrivateKeyInfo(algID, keyStruct.ToAsn1Object(), attributes);
             }
 
-            if (privateKey is ECPrivateKeyParameters)
+            if (privateKey is ECPrivateKeyParameters priv)
             {
-                ECPrivateKeyParameters priv = (ECPrivateKeyParameters) privateKey;                 
-                DerBitString publicKey = new DerBitString(ECKeyPairGenerator.GetCorrespondingPublicKey(priv).Q.GetEncoded(false));
+                var pub = ECKeyPairGenerator.GetCorrespondingPublicKey(priv);
+                var q = pub.Q;
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                int encodedLength = q.GetEncodedLength(false);
+                Span<byte> pubEncoding = encodedLength <= 512
+                    ? stackalloc byte[encodedLength]
+                    : new byte[encodedLength];
+                q.EncodeTo(false, pubEncoding);
+#else
+                byte[] pubEncoding = q.GetEncoded(false);
+#endif
+
+                DerBitString publicKey = new DerBitString(pubEncoding);
 
                 ECDomainParameters dp = priv.Parameters;
 
                 // ECGOST3410
-                if (dp is ECGost3410Parameters)
+                if (dp is ECGost3410Parameters domainParameters)
                 {
-                    ECGost3410Parameters domainParameters = (ECGost3410Parameters) dp;
-
                     Gost3410PublicKeyAlgParameters gostParams = new Gost3410PublicKeyAlgParameters(
                         (domainParameters).PublicKeyParamSet,
                         (domainParameters).DigestParamSet,
diff --git a/crypto/src/util/Arrays.cs b/crypto/src/util/Arrays.cs
index 83fafb388..f99065512 100644
--- a/crypto/src/util/Arrays.cs
+++ b/crypto/src/util/Arrays.cs
@@ -958,6 +958,15 @@ namespace Org.BouncyCastle.Utilities
             return result;
         }
 
+        internal static void Reverse<T>(T[] input, T[] output)
+        {
+            int last = input.Length - 1;
+            for (int i = 0; i <= last; ++i)
+            {
+                output[i] = input[last - i];
+            }
+        }
+
         public static T[] ReverseInPlace<T>(T[] array)
         {
             if (null == array)
diff --git a/crypto/src/x509/SubjectPublicKeyInfoFactory.cs b/crypto/src/x509/SubjectPublicKeyInfoFactory.cs
index fc0492fe4..36facc3aa 100644
--- a/crypto/src/x509/SubjectPublicKeyInfoFactory.cs
+++ b/crypto/src/x509/SubjectPublicKeyInfoFactory.cs
@@ -174,7 +174,17 @@ namespace Org.BouncyCastle.X509
                         x962 = new X962Parameters(_key.PublicKeyParamSet);
                     }
 
-                    byte[] pubKey = _key.Q.GetEncoded(false);
+                    var q = _key.Q;
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                    int encodedLength = q.GetEncodedLength(false);
+                    Span<byte> pubKey = encodedLength <= 512
+                        ? stackalloc byte[encodedLength]
+                        : new byte[encodedLength];
+                    q.EncodeTo(false, pubKey);
+#else
+                    byte[] pubKey = q.GetEncoded(false);
+#endif
 
                     AlgorithmIdentifier algID = new AlgorithmIdentifier(
                         X9ObjectIdentifiers.IdECPublicKey, x962.ToAsn1Object());
@@ -212,14 +222,22 @@ namespace Org.BouncyCastle.X509
             {
                 X448PublicKeyParameters key = (X448PublicKeyParameters)publicKey;
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                return new SubjectPublicKeyInfo(new AlgorithmIdentifier(EdECObjectIdentifiers.id_X448), key.DataSpan);
+#else
                 return new SubjectPublicKeyInfo(new AlgorithmIdentifier(EdECObjectIdentifiers.id_X448), key.GetEncoded());
+#endif
             }
 
             if (publicKey is X25519PublicKeyParameters)
             {
                 X25519PublicKeyParameters key = (X25519PublicKeyParameters)publicKey;
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                return new SubjectPublicKeyInfo(new AlgorithmIdentifier(EdECObjectIdentifiers.id_X25519), key.DataSpan);
+#else
                 return new SubjectPublicKeyInfo(new AlgorithmIdentifier(EdECObjectIdentifiers.id_X25519), key.GetEncoded());
+#endif
             }
 
             if (publicKey is Ed448PublicKeyParameters)