- Initial commit

Runtime/3rdParty/BouncyCastle/crypto/generators/Mgf1BytesGenerator.cs

@@ -0,0 +1,116 @@
+#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
+#pragma warning disable
+using System;
+
+using Best.HTTP.SecureProtocol.Org.BouncyCastle.Crypto.Parameters;
+using Best.HTTP.SecureProtocol.Org.BouncyCastle.Crypto.Utilities;
+
+namespace Best.HTTP.SecureProtocol.Org.BouncyCastle.Crypto.Generators
+{
+    /// <summary>Generator for MGF1 as defined in Pkcs 1v2</summary>
+    public sealed class Mgf1BytesGenerator
+        : IDerivationFunction
+    {
+        private readonly IDigest m_digest;
+        private readonly int m_hLen;
+
+        private byte[] m_buffer;
+
+        /// <param name="digest">the digest to be used as the source of generated bytes</param>
+        public Mgf1BytesGenerator(IDigest digest)
+        {
+            m_digest = digest;
+            m_hLen = digest.GetDigestSize();
+        }
+
+        public void Init(IDerivationParameters parameters)
+        {
+            if (!(parameters is MgfParameters mgfParameters))
+                throw new ArgumentException("MGF parameters required for MGF1Generator");
+
+            m_buffer = new byte[mgfParameters.SeedLength + 4 + m_hLen];
+            mgfParameters.GetSeed(m_buffer, 0);
+        }
+
+        /// <summary>the underlying digest.</summary>
+        public IDigest Digest => m_digest;
+
+        /// <summary>Fill <c>len</c> bytes of the output buffer with bytes generated from the derivation function.
+        /// </summary>
+        public int GenerateBytes(byte[] output, int outOff, int length)
+        {
+            Check.OutputLength(output, outOff, length, "output buffer too small");
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || UNITY_2021_2_OR_NEWER
+            return GenerateBytes(output.AsSpan(outOff, length));
+#else
+            int hashPos = m_buffer.Length - m_hLen;
+            int counterPos = hashPos - 4;
+            uint counter = 0;
+
+            m_digest.Reset();
+
+            int end = outOff + length;
+            int limit = end - m_hLen;
+
+            while (outOff <= limit)
+            {
+                Pack.UInt32_To_BE(counter++, m_buffer, counterPos);
+
+                m_digest.BlockUpdate(m_buffer, 0, hashPos);
+                m_digest.DoFinal(output, outOff);
+
+                outOff += m_hLen;
+            }
+
+            if (outOff < end)
+            {
+                Pack.UInt32_To_BE(counter, m_buffer, counterPos);
+
+                m_digest.BlockUpdate(m_buffer, 0, hashPos);
+                m_digest.DoFinal(m_buffer, hashPos);
+
+                Array.Copy(m_buffer, hashPos, output, outOff, end - outOff);
+            }
+
+            return length;
+#endif
+        }
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER || UNITY_2021_2_OR_NEWER
+        public int GenerateBytes(Span<byte> output)
+        {
+            int hashPos = m_buffer.Length - m_hLen;
+            int counterPos = hashPos - 4;
+            uint counter = 0;
+
+            m_digest.Reset();
+
+            int pos = 0, length = output.Length, limit = length - m_hLen;
+
+            while (pos <= limit)
+            {
+                Pack.UInt32_To_BE(counter++, m_buffer.AsSpan(counterPos));
+
+                m_digest.BlockUpdate(m_buffer.AsSpan(0, hashPos));
+                m_digest.DoFinal(output[pos..]);
+
+                pos += m_hLen;
+            }
+
+            if (pos < length)
+            {
+                Pack.UInt32_To_BE(counter, m_buffer.AsSpan(counterPos));
+
+                m_digest.BlockUpdate(m_buffer.AsSpan(0, hashPos));
+                m_digest.DoFinal(m_buffer.AsSpan(hashPos));
+                m_buffer.AsSpan(hashPos, length - pos).CopyTo(output[pos..]);
+            }
+
+            return length;
+        }
+#endif
+    }
+}
+#pragma warning restore
+#endif