diff --git a/xml/System.Security.Cryptography/HMAC.xml b/xml/System.Security.Cryptography/HMAC.xml
index c2e879c1487..c6edd024f42 100644
--- a/xml/System.Security.Cryptography/HMAC.xml
+++ b/xml/System.Security.Cryptography/HMAC.xml
@@ -346,9 +346,20 @@
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="source">The input to compute the HMAC code for.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+The default implementation of this method throws a <xref:System.PlatformNotSupportedException>
+because there is no managed implementation of HMAC.
+
+Derived types must override this method.
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.PlatformNotSupportedException">In all cases.</exception>
       </Docs>
     </Member>
     <Member MemberName="HashCore">
@@ -388,15 +399,13 @@
         <param name="rgb">The input data.</param>
         <param name="ib">The offset into the byte array from which to begin using data.</param>
         <param name="cb">The number of bytes in the array to use as data.</param>
-        <summary>When overridden in a derived class, routes data written to the object into the default <see cref="T:System.Security.Cryptography.HMAC" /> hash algorithm for computing the hash value.</summary>
+        <summary>When overridden in a derived class, routes data written to the object into the HMAC algorithm for computing the HMAC value.</summary>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
  This method is not called by application code.  
   
- This abstract method performs the hash computation. Every write to the cryptographic stream object passes the data through this method. For each block of data, this method updates the state of the hash object so that a correct hash value is returned at the end of the data stream.  
-  
  ]]></format>
         </remarks>
         <altmember cref="T:System.Security.Cryptography.HashAlgorithm" />
@@ -433,8 +442,8 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic stream object.</summary>
-        <returns>The computed hash code in a byte array.</returns>
+        <summary>When overridden in a derived class, finalizes the HMAC computation after the last data is processed by the algorithm.</summary>
+        <returns>The computed HMAC value in a byte array.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
@@ -562,8 +571,8 @@
         <ReturnType>System.Byte[]</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>Gets or sets the key to use in the hash algorithm.</summary>
-        <value>The key to use in the hash algorithm.</value>
+        <summary>Gets or sets the key to use in the HMAC calculation.</summary>
+        <value>The key to use in the HMAC calculation.</value>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
@@ -611,11 +620,23 @@
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="destination">The buffer to receive the HMAC value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the HMAC computation after the last data is processed by the HMAC algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the HMAC value; otherwise, <see langword="false"/>.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+The default implementation of this method throws a <xref:System.PlatformNotSupportedException>
+because there is no managed implementation of HMAC.
+
+Derived types must override this method.
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.PlatformNotSupportedException">The method is not overriden in the derived type.</exception>
       </Docs>
     </Member>
   </Members>
diff --git a/xml/System.Security.Cryptography/HMACMD5.xml b/xml/System.Security.Cryptography/HMACMD5.xml
index 2da55cb39b8..30a59772815 100644
--- a/xml/System.Security.Cryptography/HMACMD5.xml
+++ b/xml/System.Security.Cryptography/HMACMD5.xml
@@ -199,8 +199,9 @@
         <Parameter Name="disposing" Type="System.Boolean" Index="0" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="disposing">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="disposing">
+          <see langword="true" /> to release both managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.</param>
+        <summary>Releases the unmanaged resources used by the <see cref="T:System.Security.Cryptography.HMACMD5" /> and optionally releases the managed resources.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -230,8 +231,8 @@
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the HMAC for.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -267,10 +268,10 @@
         <Parameter Name="cb" Type="System.Int32" Index="2" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="rgb">To be added.</param>
-        <param name="ib">To be added.</param>
-        <param name="cb">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="rgb">The input to compute the HMAC for.</param>
+        <param name="ib">The offset into the byte array from which to begin using data.</param>
+        <param name="cb">The number of bytes in the byte array to use as data.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -302,8 +303,8 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Finalizes the HMAC computation after the last data is processed by the algorithm.</summary>
+        <returns>The computed HMAC value in a byte array.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -331,8 +332,8 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the size, in bits, of the computed HMAC.</summary>
+        <value>The size, in bits, of the computed HMAC.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -364,7 +365,7 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Resets the hash algorithm to its initial state.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -395,8 +396,8 @@
         <ReturnType>System.Byte[]</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets or sets the key to use in the HMAC calculation.</summary>
+        <value>The key to use in the HMAC calculation.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -427,10 +428,11 @@
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the HMAC value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the HMAC computation after the last data is processed by the HMAC algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the HMAC value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/HMACSHA1.xml b/xml/System.Security.Cryptography/HMACSHA1.xml
index f78832de34c..5a4ecc77e35 100644
--- a/xml/System.Security.Cryptography/HMACSHA1.xml
+++ b/xml/System.Security.Cryptography/HMACSHA1.xml
@@ -316,8 +316,8 @@ Releases the unmanaged resources used by the <see cref="T:System.Security.Crypto
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the HMAC for.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -390,8 +390,8 @@ Releases the unmanaged resources used by the <see cref="T:System.Security.Crypto
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Finalizes the HMAC computation after the last data is processed by the algorithm.</summary>
+        <returns>The computed HMAC value in a byte array.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -446,8 +446,8 @@ Releases the unmanaged resources used by the <see cref="T:System.Security.Crypto
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the size, in bits, of the computed HMAC.</summary>
+        <value>The size, in bits, of the computed HMAC.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -480,7 +480,7 @@ Releases the unmanaged resources used by the <see cref="T:System.Security.Crypto
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>Initializes an instance of <see cref="T:System.Security.Cryptography.HMACSHA1" />.</summary>
+        <summary>Resets the hash algorithm to its initial state.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -544,10 +544,11 @@ Releases the unmanaged resources used by the <see cref="T:System.Security.Crypto
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the HMAC value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the HMAC computation after the last data is processed by the HMAC algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the HMAC value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/HMACSHA256.xml b/xml/System.Security.Cryptography/HMACSHA256.xml
index a84474290fd..5f07c9f7649 100644
--- a/xml/System.Security.Cryptography/HMACSHA256.xml
+++ b/xml/System.Security.Cryptography/HMACSHA256.xml
@@ -195,8 +195,9 @@
         <Parameter Name="disposing" Type="System.Boolean" Index="0" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="disposing">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="disposing">
+          <see langword="true" /> to release both managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.</param>
+        <summary>Releases the unmanaged resources used by the <see cref="T:System.Security.Cryptography.HMACSHA256" /> and optionally releases the managed resources.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -226,8 +227,8 @@
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the HMAC for.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -263,10 +264,10 @@
         <Parameter Name="cb" Type="System.Int32" Index="2" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="rgb">To be added.</param>
-        <param name="ib">To be added.</param>
-        <param name="cb">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="rgb">The input to compute the HMAC for.</param>
+        <param name="ib">The offset into the byte array from which to begin using data.</param>
+        <param name="cb">The number of bytes in the byte array to use as data.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -298,8 +299,8 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Finalizes the HMAC computation after the last data is processed by the algorithm.</summary>
+        <returns>The computed HMAC value in a byte array.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -327,8 +328,8 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the size, in bits, of the computed HMAC.</summary>
+        <value>The size, in bits, of the computed HMAC.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -360,7 +361,7 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Resets the hash algorithm to its initial state.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -391,8 +392,8 @@
         <ReturnType>System.Byte[]</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets or sets the key to use in the HMAC calculation.</summary>
+        <value>The key to use in the HMAC calculation.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -423,10 +424,11 @@
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the HMAC value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the HMAC computation after the last data is processed by the HMAC algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the HMAC value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/HMACSHA384.xml b/xml/System.Security.Cryptography/HMACSHA384.xml
index 60caa40cac3..05835f56798 100644
--- a/xml/System.Security.Cryptography/HMACSHA384.xml
+++ b/xml/System.Security.Cryptography/HMACSHA384.xml
@@ -193,8 +193,9 @@
         <Parameter Name="disposing" Type="System.Boolean" Index="0" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="disposing">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="disposing">
+          <see langword="true" /> to release both managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.</param>
+        <summary>Releases the unmanaged resources used by the <see cref="T:System.Security.Cryptography.HMACSHA384" /> and optionally releases the managed resources.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -224,8 +225,8 @@
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the HMAC for.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -261,10 +262,10 @@
         <Parameter Name="cb" Type="System.Int32" Index="2" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="rgb">To be added.</param>
-        <param name="ib">To be added.</param>
-        <param name="cb">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="rgb">The input to compute the HMAC for.</param>
+        <param name="ib">The offset into the byte array from which to begin using data.</param>
+        <param name="cb">The number of bytes in the byte array to use as data.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -296,8 +297,8 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Finalizes the HMAC computation after the last data is processed by the algorithm.</summary>
+        <returns>The computed HMAC value in a byte array.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -325,8 +326,8 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the size, in bits, of the computed HMAC.</summary>
+        <value>The size, in bits, of the computed HMAC.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -358,7 +359,7 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Resets the hash algorithm to its initial state.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -389,8 +390,8 @@
         <ReturnType>System.Byte[]</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets or sets the key to use in the HMAC calculation.</summary>
+        <value>The key to use in the HMAC calculation.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -475,10 +476,11 @@ public static void Test()
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the HMAC value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the HMAC computation after the last data is processed by the HMAC algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the HMAC value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/HMACSHA512.xml b/xml/System.Security.Cryptography/HMACSHA512.xml
index 9fe856543de..fcf61fbe46c 100644
--- a/xml/System.Security.Cryptography/HMACSHA512.xml
+++ b/xml/System.Security.Cryptography/HMACSHA512.xml
@@ -193,8 +193,9 @@
         <Parameter Name="disposing" Type="System.Boolean" Index="0" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="disposing">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="disposing">
+          <see langword="true" /> to release both managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.</param>
+        <summary>Releases the unmanaged resources used by the <see cref="T:System.Security.Cryptography.HMACSHA512" /> and optionally releases the managed resources.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -224,8 +225,8 @@
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the HMAC for.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -261,10 +262,10 @@
         <Parameter Name="cb" Type="System.Int32" Index="2" FrameworkAlternate="netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netstandard-1.3;netstandard-1.4;netstandard-1.6;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="rgb">To be added.</param>
-        <param name="ib">To be added.</param>
-        <param name="cb">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="rgb">The input to compute the HMAC for.</param>
+        <param name="ib">The offset into the byte array from which to begin using data.</param>
+        <param name="cb">The number of bytes in the byte array to use as data.</param>
+        <summary>Routes data written to the object into the HMAC algorithm for computing the HMAC.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -296,8 +297,8 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Finalizes the HMAC computation after the last data is processed by the algorithm.</summary>
+        <returns>The computed HMAC value in a byte array.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -325,8 +326,8 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the size, in bits, of the computed HMAC.</summary>
+        <value>The size, in bits, of the computed HMAC.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -358,7 +359,7 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Resets the hash algorithm to its initial state.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -389,8 +390,8 @@
         <ReturnType>System.Byte[]</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets or sets the key to use in the HMAC calculation.</summary>
+        <value>The key to use in the HMAC calculation.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -475,10 +476,11 @@ public static void Test()
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the HMAC value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the HMAC computation after the last data is processed by the HMAC algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the HMAC value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/HashAlgorithm.xml b/xml/System.Security.Cryptography/HashAlgorithm.xml
index fe9c262825f..bbf9e13f268 100644
--- a/xml/System.Security.Cryptography/HashAlgorithm.xml
+++ b/xml/System.Security.Cryptography/HashAlgorithm.xml
@@ -714,9 +714,18 @@ The following example calculates the <xref:System.Security.Cryptography.SHA256>
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="source">The input to compute the hash code for.</param>
+        <summary>Routes data written to the object into the hash algorithm for computing the hash.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+The default implementation of this method copies `source` to a temporary array and calls <xref:System.Security.Cryptography.HashAlgorithm.HashCore(System.Byte[],System.Int32,System.Int32)>.
+    
+Derived types should override this method to avoid the intermediate data copying.
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="HashCore">
@@ -764,7 +773,7 @@ The following example calculates the <xref:System.Security.Cryptography.SHA256>
 ## Remarks  
  This method is not called by application code.  
   
- This abstract method performs the hash computation. Every write to the cryptographic stream object passes the data through this method. For each block of data, this method updates the state of the hash object so a correct hash value is returned at the end of the data stream.  
+ This abstract method performs the hash computation. Every write to the cryptographic hash algorithm passes the data through this method. For each block of data, this method updates the state of the hash object so a correct hash value is returned at the end of the data.  
   
  ]]></format>
         </remarks>
@@ -801,13 +810,13 @@ The following example calculates the <xref:System.Security.Cryptography.SHA256>
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic stream object.</summary>
+        <summary>When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic hash algorithm.</summary>
         <returns>The computed hash code.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- This method finalizes any partial computation and returns the correct hash value for the data stream.  
+ This method finalizes any partial computation and returns the correct hash value for the data.  
   
  ]]></format>
         </remarks>
@@ -965,7 +974,7 @@ The following example calculates the <xref:System.Security.Cryptography.SHA256>
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>Initializes an implementation of the <see cref="T:System.Security.Cryptography.HashAlgorithm" /> class.</summary>
+        <summary>Resets the hash algorithm to its initial state.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -1333,11 +1342,12 @@ For more information about Dispose and Finalize, see [Cleaning Up Unmanaged Reso
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="2" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="source">The input to compute the hash code for.</param>
+        <param name="destination">The buffer to receive the hash value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to compute the hash value for the specified byte array.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the hash value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -1368,11 +1378,24 @@ For more information about Dispose and Finalize, see [Cleaning Up Unmanaged Reso
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="destination">The buffer to receive the hash value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the hash computation after the last data is processed by the hash algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the hash value; otherwise, <see langword="false"/>.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+The default implementation of this method is to call <xref:System.Security.Cryptography.HashAlgorithm.HashFinal> and copy the result to `destination`.
+    
+Derived types should override this method to avoid the intermediate array creation.
+
+All calls to this method by the <xref:System.Security.Cryptography.HashAlgorithm> class have already verified that `destination` is long enough based on the <xref:System.Security.Cryptography.HashAlgorithm.HashSize> property,
+so `false` return values are unexpected.
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
   </Members>
diff --git a/xml/System.Security.Cryptography/IncrementalHash.xml b/xml/System.Security.Cryptography/IncrementalHash.xml
index df5624d9fcf..f74d08ffac4 100644
--- a/xml/System.Security.Cryptography/IncrementalHash.xml
+++ b/xml/System.Security.Cryptography/IncrementalHash.xml
@@ -152,9 +152,10 @@
         <Parameter Name="data" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="data">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="data">The data to process.</param>
+        <summary>Appends the specified data to the data already processed in the hash or Hash-based Message Authentication Code (HMAC).</summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ObjectDisposedException">The <see cref="T:System.Security.Cryptography.IncrementalHash" /> object has already been disposed.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendData">
@@ -383,7 +384,7 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>Retrieves the hash or Hash-based Message Authentication Code (HMAC) for the data accumulated from prior calls to the <see cref="M:System.Security.Cryptography.IncrementalHash.AppendData(System.Byte[])" /> method,  and resets the object to its initial state.</summary>
+        <summary>Retrieves the hash or Hash-based Message Authentication Code (HMAC) for the data accumulated from prior calls to the <see cref="Overload:System.Security.Cryptography.IncrementalHash.AppendData" /> methods,  and resets the object to its initial state.</summary>
         <returns>The computed hash or HMAC.</returns>
         <remarks>To be added.</remarks>
         <exception cref="T:System.ObjectDisposedException">The <see cref="T:System.Security.Cryptography.IncrementalHash" /> object has already been disposed.</exception>
@@ -416,11 +417,12 @@
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="destination">The buffer to receive the hash or Hash-Based Message Authentication Code (HMAC) value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the hash computation after the last data is processed by the hash algorithm.</summary>
+        <summary>Attempts to retrieve the hash or Hash-based Message Authentication Code (HMAC) for the data accumulated from prior calls to the <see cref="Overload:System.Security.Cryptography.IncrementalHash.AppendData" /> methods,  and resets the object to its initial state.</summary>
+        <returns><see langword="true"/> if <paramref name="destination"/> is long enough to receive the hash or HMAC value; otherwise, <see langword="false"/>.</returns>
+        <exception cref="T:System.ObjectDisposedException">The <see cref="T:System.Security.Cryptography.IncrementalHash" /> object has already been disposed.</exception>
       </Docs>
     </Member>
   </Members>
diff --git a/xml/System.Security.Cryptography/SHA1Managed.xml b/xml/System.Security.Cryptography/SHA1Managed.xml
index 8dc6490fab3..5119403d133 100644
--- a/xml/System.Security.Cryptography/SHA1Managed.xml
+++ b/xml/System.Security.Cryptography/SHA1Managed.xml
@@ -160,7 +160,7 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Frees resources and performs other cleanup operations for this object before it is reclaimed by garbage collection.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -192,8 +192,8 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the hash code for.</param>
+        <summary>Routes data written to the object into the hash algorithm for computing the hash.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -362,10 +362,11 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the hash value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the hash computation after the last data is processed by the hash algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the hash value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/SHA256Managed.xml b/xml/System.Security.Cryptography/SHA256Managed.xml
index 2e1721d32c8..2fa8de4a989 100644
--- a/xml/System.Security.Cryptography/SHA256Managed.xml
+++ b/xml/System.Security.Cryptography/SHA256Managed.xml
@@ -171,7 +171,7 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <ReturnType>System.Void</ReturnType></ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Frees resources and performs other cleanup operations for this object before it is reclaimed by garbage collection.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -203,8 +203,8 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the hash code for.</param>
+        <summary>Routes data written to the object into the hash algorithm for computing the hash.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -398,10 +398,11 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the hash value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the hash computation after the last data is processed by the hash algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the hash value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/SHA384Managed.xml b/xml/System.Security.Cryptography/SHA384Managed.xml
index b29e04b6dd5..46297b526f6 100644
--- a/xml/System.Security.Cryptography/SHA384Managed.xml
+++ b/xml/System.Security.Cryptography/SHA384Managed.xml
@@ -172,7 +172,7 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Frees resources and performs other cleanup operations for this object before it is reclaimed by garbage collection.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -204,8 +204,8 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the hash code for.</param>
+        <summary>Routes data written to the object into the hash algorithm for computing the hash.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -409,10 +409,11 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the hash value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the hash computation after the last data is processed by the hash algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the hash value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Security.Cryptography/SHA512Managed.xml b/xml/System.Security.Cryptography/SHA512Managed.xml
index 5fc5d326aa9..b90b1c00ecf 100644
--- a/xml/System.Security.Cryptography/SHA512Managed.xml
+++ b/xml/System.Security.Cryptography/SHA512Managed.xml
@@ -170,7 +170,7 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Frees resources and performs other cleanup operations for this object before it is reclaimed by garbage collection.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -202,8 +202,8 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="source" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="0" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="source">The input to compute the hash code for.</param>
+        <summary>Routes data written to the object into the hash algorithm for computing the hash.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -407,10 +407,11 @@ This method is called by the public <xref:System.Security.Cryptography.HashAlgor
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="destination">To be added.</param>
-        <param name="bytesWritten">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="destination">The buffer to receive the hash value.</param>
+        <param name="bytesWritten">When this method returns, the total number of bytes written into <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to finalize the hash computation after the last data is processed by the hash algorithm.</summary>
+        <returns>
+          <see langword="true"/> if <paramref name="destination"/> is long enough to receive the hash value; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>