Refactoring around digest calculation

7 files changed, 98 insertions, 72 deletions

diff --git a/crypto/src/cmp/CertificateConfirmationContentBuilder.cs b/crypto/src/cmp/CertificateConfirmationContentBuilder.cs
index faf0cf998..873b58b2e 100644
--- a/crypto/src/cmp/CertificateConfirmationContentBuilder.cs
+++ b/crypto/src/cmp/CertificateConfirmationContentBuilder.cs
@@ -6,7 +6,6 @@ using Org.BouncyCastle.Asn1.Cmp;
 using Org.BouncyCastle.Asn1.X509;
 using Org.BouncyCastle.Math;
 using Org.BouncyCastle.Operators.Utilities;
-using Org.BouncyCastle.Security;
 using Org.BouncyCastle.X509;
 
 namespace Org.BouncyCastle.Cmp
@@ -62,17 +61,11 @@ namespace Org.BouncyCastle.Cmp
             Asn1EncodableVector v = new Asn1EncodableVector(m_acceptedCerts.Count);
             for (int i = 0; i != m_acceptedCerts.Count; i++)
             {
-                CmpCertificate cmpCertificate = m_acceptedCerts[i];
-                AlgorithmIdentifier signatureAlgorithm = m_acceptedSignatureAlgorithms[i];
-                DerInteger reqID = m_acceptedReqIDs[i];
+                var certHash = CmpUtilities.CalculateCertHash(m_acceptedCerts[i], m_acceptedSignatureAlgorithms[i],
+                    m_digestAlgorithmFinder);
+                var reqID = m_acceptedReqIDs[i];
 
-                var digestAlgorithm = m_digestAlgorithmFinder.Find(signatureAlgorithm)
-                    ?? throw new CmpException("cannot find algorithm for digest from signature");
-
-                byte[] digest = DigestUtilities.CalculateDigest(digestAlgorithm.Algorithm,
-                    cmpCertificate.GetEncoded(Asn1Encodable.Der));
-
-                v.Add(new CertStatus(digest, reqID));
+                v.Add(new CertStatus(certHash, reqID));
             }
 
             var content = CertConfirmContent.GetInstance(new DerSequence(v));
diff --git a/crypto/src/cmp/CertificateStatus.cs b/crypto/src/cmp/CertificateStatus.cs
index 482e9f7f3..4c45a3cb8 100644
--- a/crypto/src/cmp/CertificateStatus.cs
+++ b/crypto/src/cmp/CertificateStatus.cs
@@ -1,11 +1,9 @@
 using System;
 
-using Org.BouncyCastle.Asn1;
 using Org.BouncyCastle.Asn1.Cmp;
 using Org.BouncyCastle.Asn1.X509;
 using Org.BouncyCastle.Math;
 using Org.BouncyCastle.Operators.Utilities;
-using Org.BouncyCastle.Security;
 using Org.BouncyCastle.Utilities;
 using Org.BouncyCastle.X509;
 
@@ -38,13 +36,9 @@ namespace Org.BouncyCastle.Cmp
 
         public virtual bool IsVerified(CmpCertificate cmpCertificate, AlgorithmIdentifier signatureAlgorithm)
         {
-            AlgorithmIdentifier digestAlgorithm = m_digestAlgorithmFinder.Find(signatureAlgorithm)
-                ?? throw new CmpException("cannot find algorithm for digest from signature");
+            var certHash = CmpUtilities.CalculateCertHash(cmpCertificate, signatureAlgorithm, m_digestAlgorithmFinder);
 
-            byte[] digest = DigestUtilities.CalculateDigest(digestAlgorithm.Algorithm,
-                cmpCertificate.GetEncoded(Asn1Encodable.Der));
-
-            return Arrays.FixedTimeEquals(m_certStatus.CertHash.GetOctets(), digest);
+            return Arrays.FixedTimeEquals(m_certStatus.CertHash.GetOctets(), certHash);
         }
     }
 }
diff --git a/crypto/src/cmp/CmpUtilities.cs b/crypto/src/cmp/CmpUtilities.cs
new file mode 100644
index 000000000..d4e2c89bf
--- /dev/null
+++ b/crypto/src/cmp/CmpUtilities.cs
@@ -0,0 +1,18 @@
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Operators.Utilities;
+
+namespace Org.BouncyCastle.Cmp
+{
+    internal static class CmpUtilities
+    {
+        internal static byte[] CalculateCertHash(Asn1Encodable asn1Encodable, AlgorithmIdentifier signatureAlgorithm,
+            IDigestAlgorithmFinder digestAlgorithmFinder)
+        {
+            var digestAlgorithm = digestAlgorithmFinder.Find(signatureAlgorithm)
+                ?? throw new CmpException("cannot find digest algorithm from signature algorithm");
+
+            return X509.X509Utilities.CalculateDigest(digestAlgorithm.Algorithm, asn1Encodable);
+        }
+    }
+}
diff --git a/crypto/src/crypto/operators/Asn1DigestFactory.cs b/crypto/src/crypto/operators/Asn1DigestFactory.cs
index 0c1b6fb41..753047937 100644
--- a/crypto/src/crypto/operators/Asn1DigestFactory.cs
+++ b/crypto/src/crypto/operators/Asn1DigestFactory.cs
@@ -1,9 +1,5 @@
-using System;
-using System.IO;
-
-using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1;
 using Org.BouncyCastle.Asn1.X509;
-using Org.BouncyCastle.Crypto.IO;
 using Org.BouncyCastle.Security;
 
 namespace Org.BouncyCastle.Crypto.Operators
@@ -11,62 +7,24 @@ namespace Org.BouncyCastle.Crypto.Operators
     public class Asn1DigestFactory
         : IDigestFactory
     {
-        public static Asn1DigestFactory Get(DerObjectIdentifier oid)
-        {
-            return new Asn1DigestFactory(DigestUtilities.GetDigest(oid), oid);          
-        }
+        public static Asn1DigestFactory Get(DerObjectIdentifier oid) =>
+            new Asn1DigestFactory(DigestUtilities.GetDigest(oid), oid);          
 
-        public static Asn1DigestFactory Get(string mechanism)
-        {
-            DerObjectIdentifier oid = DigestUtilities.GetObjectIdentifier(mechanism);
-            return new Asn1DigestFactory(DigestUtilities.GetDigest(oid), oid);
-        }
+        public static Asn1DigestFactory Get(string mechanism) => Get(DigestUtilities.GetObjectIdentifier(mechanism));
 
-        private readonly IDigest mDigest;
-        private readonly DerObjectIdentifier mOid;
+        private readonly IDigest m_digest;
+        private readonly DerObjectIdentifier m_oid;
 
         public Asn1DigestFactory(IDigest digest, DerObjectIdentifier oid)
         {
-            this.mDigest = digest;
-            this.mOid = oid;
-        }    
-
-        public virtual object AlgorithmDetails
-        {
-            get { return new AlgorithmIdentifier(mOid); }
+            m_digest = digest;
+            m_oid = oid;
         }
 
-        public virtual int DigestLength
-        {
-            get { return mDigest.GetDigestSize(); }
-        }
+        public virtual object AlgorithmDetails => new AlgorithmIdentifier(m_oid);
 
-        public virtual IStreamCalculator<IBlockResult> CreateCalculator()
-        {
-            return new DfDigestStream(mDigest);
-        }
-    }
-
-    internal class DfDigestStream
-        : IStreamCalculator<SimpleBlockResult>
-    {
-        private readonly DigestSink mStream;
-
-        public DfDigestStream(IDigest digest)
-        {          
-            this.mStream = new DigestSink(digest);
-        }
+        public virtual int DigestLength => m_digest.GetDigestSize();
 
-        public Stream Stream
-        {
-            get { return mStream; }
-        }
-
-        public SimpleBlockResult GetResult()
-        {
-            byte[] result = new byte[mStream.Digest.GetDigestSize()];
-            mStream.Digest.DoFinal(result, 0);
-            return new SimpleBlockResult(result);
-        }
+        public virtual IStreamCalculator<IBlockResult> CreateCalculator() => new DefaultDigestCalculator(m_digest);
     }
 }
diff --git a/crypto/src/crypto/operators/DefaultDigestCalculator.cs b/crypto/src/crypto/operators/DefaultDigestCalculator.cs
new file mode 100644
index 000000000..78ac30983
--- /dev/null
+++ b/crypto/src/crypto/operators/DefaultDigestCalculator.cs
@@ -0,0 +1,21 @@
+using System.IO;
+
+using Org.BouncyCastle.Crypto.IO;
+
+namespace Org.BouncyCastle.Crypto.Operators
+{
+    public sealed class DefaultDigestCalculator
+        : IStreamCalculator<IBlockResult>
+    {
+        private readonly DigestSink m_digestSink;
+
+        public DefaultDigestCalculator(IDigest digest)
+        {
+            m_digestSink = new DigestSink(digest);
+        }
+
+        public Stream Stream => m_digestSink;
+
+        public IBlockResult GetResult() => new DefaultDigestResult(m_digestSink.Digest);
+    }
+}
diff --git a/crypto/src/crypto/operators/DefaultDigestResult.cs b/crypto/src/crypto/operators/DefaultDigestResult.cs
new file mode 100644
index 000000000..60625c421
--- /dev/null
+++ b/crypto/src/crypto/operators/DefaultDigestResult.cs
@@ -0,0 +1,27 @@
+using System;
+
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Crypto.Operators
+{
+    public sealed class DefaultDigestResult
+        : IBlockResult
+    {
+        private readonly IDigest m_digest;
+
+        public DefaultDigestResult(IDigest digest)
+        {
+            m_digest = digest;
+        }
+
+        public byte[] Collect() => DigestUtilities.DoFinal(m_digest);
+
+        public int Collect(byte[] buf, int off) => m_digest.DoFinal(buf, off);
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        public int Collect(Span<byte> output) => m_digest.DoFinal(output);
+#endif
+
+        public int GetMaxResultLength() => m_digest.GetDigestSize();
+    }
+}
diff --git a/crypto/src/x509/X509Utilities.cs b/crypto/src/x509/X509Utilities.cs
index 45fa75916..5051b1b4e 100644
--- a/crypto/src/x509/X509Utilities.cs
+++ b/crypto/src/x509/X509Utilities.cs
@@ -10,6 +10,8 @@ using Org.BouncyCastle.Asn1.TeleTrust;
 using Org.BouncyCastle.Asn1.X509;
 using Org.BouncyCastle.Asn1.X9;
 using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Operators;
+using Org.BouncyCastle.Security;
 using Org.BouncyCastle.Utilities;
 using Org.BouncyCastle.Utilities.Collections;
 
@@ -127,6 +129,14 @@ namespace Org.BouncyCastle.X509
 			m_exParams.Add("SHA512WITHRSAANDMGF1", CreatePssParams(sha512AlgId, 64));
 		}
 
+		internal static byte[] CalculateDigest(DerObjectIdentifier oid, Asn1Encodable asn1Encodable)
+		{
+            var digest = DigestUtilities.GetDigest(oid);
+            var digestCalculator = new DefaultDigestCalculator(digest);
+            var digestResult = CalculateResult(digestCalculator, asn1Encodable);
+			return digestResult.Collect();
+        }
+
         internal static TResult CalculateResult<TResult>(IStreamCalculator<TResult> streamCalculator,
             Asn1Encodable asn1Encodable)
         {
@@ -195,6 +205,11 @@ namespace Org.BouncyCastle.X509
             return CollectDerBitString(result);
         }
 
+        internal static DerBitString GenerateDigest(IDigestFactory digestFactory, Asn1Encodable asn1Encodable)
+        {
+            return GenerateBitString(digestFactory.CreateCalculator(), asn1Encodable);
+        }
+
         internal static DerBitString GenerateMac(IMacFactory macFactory, Asn1Encodable asn1Encodable)
         {
 			return GenerateBitString(macFactory.CreateCalculator(), asn1Encodable);