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Assets/BestHTTP/SecureProtocol/crypto/tls/TlsRsaSigner.cs

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+#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
+
+using System;
+
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Encodings;
+using Org.BouncyCastle.Crypto.Engines;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Signers;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Tls
+{
+    public class TlsRsaSigner
+        :   AbstractTlsSigner
+    {
+        public override byte[] GenerateRawSignature(SignatureAndHashAlgorithm algorithm,
+            AsymmetricKeyParameter privateKey, byte[] hash)
+        {
+            ISigner signer = MakeSigner(algorithm, true, true,
+                new ParametersWithRandom(privateKey, this.mContext.SecureRandom));
+            signer.BlockUpdate(hash, 0, hash.Length);
+            return signer.GenerateSignature();
+        }
+
+        public override bool VerifyRawSignature(SignatureAndHashAlgorithm algorithm, byte[] sigBytes,
+            AsymmetricKeyParameter publicKey, byte[] hash)
+        {
+            ISigner signer = MakeSigner(algorithm, true, false, publicKey);
+            signer.BlockUpdate(hash, 0, hash.Length);
+            return signer.VerifySignature(sigBytes);
+        }
+
+        public override ISigner CreateSigner(SignatureAndHashAlgorithm algorithm, AsymmetricKeyParameter privateKey)
+        {
+            return MakeSigner(algorithm, false, true, new ParametersWithRandom(privateKey, this.mContext.SecureRandom));
+        }
+
+        public override ISigner CreateVerifyer(SignatureAndHashAlgorithm algorithm, AsymmetricKeyParameter publicKey)
+        {
+            return MakeSigner(algorithm, false, false, publicKey);
+        }
+
+        public override bool IsValidPublicKey(AsymmetricKeyParameter publicKey)
+        {
+            return publicKey is RsaKeyParameters && !publicKey.IsPrivate;
+        }
+
+        protected virtual ISigner MakeSigner(SignatureAndHashAlgorithm algorithm, bool raw, bool forSigning,
+            ICipherParameters cp)
+        {
+            if ((algorithm != null) != TlsUtilities.IsTlsV12(mContext))
+                throw new InvalidOperationException();
+            if (algorithm != null && algorithm.Signature != SignatureAlgorithm.rsa)
+                throw new InvalidOperationException();
+
+            IDigest d;
+            if (raw)
+            {
+                d = new NullDigest();
+            }
+            else if (algorithm == null)
+            {
+                d = new CombinedHash();
+            }
+            else
+            {
+                d = TlsUtilities.CreateHash(algorithm.Hash);
+            }
+
+            ISigner s;
+            if (algorithm != null)
+            {
+                /*
+                 * RFC 5246 4.7. In RSA signing, the opaque vector contains the signature generated
+                 * using the RSASSA-PKCS1-v1_5 signature scheme defined in [PKCS1].
+                 */
+                s = new RsaDigestSigner(d, TlsUtilities.GetOidForHashAlgorithm(algorithm.Hash));
+            }
+            else
+            {
+                /*
+                 * RFC 5246 4.7. Note that earlier versions of TLS used a different RSA signature scheme
+                 * that did not include a DigestInfo encoding.
+                 */
+                s = new GenericSigner(CreateRsaImpl(), d);
+            }
+            s.Init(forSigning, cp);
+            return s;
+        }
+
+        protected virtual IAsymmetricBlockCipher CreateRsaImpl()
+        {
+            /*
+             * RFC 5264 7.4.7.1. Implementation note: It is now known that remote timing-based attacks
+             * on TLS are possible, at least when the client and server are on the same LAN.
+             * Accordingly, implementations that use static RSA keys MUST use RSA blinding or some other
+             * anti-timing technique, as described in [TIMING].
+             */
+            return new Pkcs1Encoding(new RsaBlindedEngine());
+        }
+    }
+}
+
+#endif