diff --git a/xml/System.Security.Cryptography/ECDiffieHellman.xml b/xml/System.Security.Cryptography/ECDiffieHellman.xml
index 25d5a1d3fcd..745b18a8f95 100644
--- a/xml/System.Security.Cryptography/ECDiffieHellman.xml
+++ b/xml/System.Security.Cryptography/ECDiffieHellman.xml
@@ -262,7 +262,7 @@
         <AssemblyVersion>4.0.0.0</AssemblyVersion>
       </AssemblyInfo>
       <Docs>
-        <summary>Derives bytes that can be used as a key using a hash function .</summary>
+        <summary>Performs key derivation using a specified hash algorithm.</summary>
       </Docs>
     </MemberGroup>
     <Member MemberName="DeriveKeyFromHash">
@@ -294,9 +294,9 @@
       </Parameters>
       <Docs>
         <param name="otherPartyPublicKey">The other party's public key.</param>
-        <param name="hashAlgorithm">The hash algorithm  to use to derive the key material.</param>
-        <summary>Derives bytes that can be used as a key using a hash function, given another party's public key and hash algorithm's name.</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
+        <param name="hashAlgorithm">The hash algorithm to use to derive the key material.</param>
+        <summary>Performs key derivation using a specified hash algorithm.</summary>
+        <returns>The hash of the shared secret.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
@@ -306,7 +306,19 @@
  ]]></format>
         </remarks>
         <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is over a different curve than this key.</exception>
+          The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.
+</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyFromHash">
@@ -340,15 +352,37 @@
       </Parameters>
       <Docs>
         <param name="otherPartyPublicKey">The other party's public key.</param>
-        <param name="hashAlgorithm">The hash algorithm  to use to derive the key material.</param>
+        <param name="hashAlgorithm">The hash algorithm to use to derive the key material.</param>
         <param name="secretPrepend">A value to prepend to the derived secret before hashing.</param>
         <param name="secretAppend">A value to append to the derived secret before hashing.</param>
-        <summary>When implemented in a derived class, derives bytes that can be used as a key using a hash function, given another party's public key, hash algorithm's name, a prepend value and an append value.</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
-        <remarks>To be added.</remarks>
+        <summary>When implemented in a derived class, performs key derivation using a specified hash algorithm with optional prepended or appended data.</summary>
+        <returns>The hash of the shared secret after prepending or appending data as requested.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+This method internally performs the Elliptic Curve Diffie-Hellman key agreement to produce the shared secret (`z`).
+The return value from this method is the result of `HASH(secretPrepend || z || secretAppend)` using the specified hash algorithm, where `||` signifies concatenation.
+
+If the value of `secretPrepend` or `secretAppend` is `null`, they are treated as empty arrays.  
+
+ ]]></format>
+        </remarks>
         <exception cref="T:System.NotImplementedException">A derived class must override this method.</exception>
-        <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is over a different curve than this key.</exception>
+        <exception cref="T:System.ArgumentException">The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.
+</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="DeriveKeyFromHmac">
@@ -357,7 +391,7 @@
         <AssemblyVersion>4.0.0.0</AssemblyVersion>
       </AssemblyInfo>
       <Docs>
-        <summary>Derives bytes that can be used as a key using a Hash-based Message Authentication Code (HMAC).</summary>
+        <summary>Performs key derivation using a specified HMAC (Hash-based Message Authentication Code) algorithm.</summary>
       </Docs>
     </MemberGroup>
     <Member MemberName="DeriveKeyFromHmac">
@@ -392,8 +426,8 @@
         <param name="otherPartyPublicKey">The other party's public key.</param>
         <param name="hashAlgorithm">The hash algorithm to use to derive the key material.</param>
         <param name="hmacKey">The key for the HMAC.</param>
-        <summary>Derives bytes that can be used as a key using a Hash-based Message Authentication Code (HMAC).</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
+        <summary>Performs key derivation using a specified HMAC (Hash-based Message Authentication Code) algorithm.</summary>
+        <returns>The HMAC of the shared secret.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
@@ -402,8 +436,19 @@
   
  ]]></format>
         </remarks>
-        <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is over a different curve than this key.</exception>
+        <exception cref="T:System.ArgumentException">The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.
+</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyFromHmac">
@@ -442,12 +487,35 @@
         <param name="hmacKey">The key for the HMAC.</param>
         <param name="secretPrepend">A value to prepend to the derived secret before hashing.</param>
         <param name="secretAppend">A value to append to the derived secret before hashing.</param>
-        <summary>When implemented in a derived class, derives bytes that can be used as a key using a Hash-based Message Authentication Code (HMAC).</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
-        <remarks>To be added.</remarks>
+        <summary>When implemented in a derived class, performs key derivation using a specified HMAC (Hash-based Message Authentication Code) algorithm with optional prepended or appended data.</summary>
+        <returns>The HMAC of the shared secret after prepending or appending data as requested.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+This method internally performs the Elliptic Curve Diffie-Hellman key agreement to produce the shared secret (`z`).
+
+When `hmacKey` is `null`, the return value from this method is the result of `HMAC-HASH(z, secretPrepend || z || secretAppend)` using the specified HMAC algorithm, where `||` signifies concatenation. Otherwise, the return value from this method is the result of `HMAC-HASH(hmacKey, secretPrepend || z || secretAppend)`.
+
+If the value of `secretPrepend` or `secretAppend` is `null`, they are treated as empty arrays.  
+
+ ]]></format>
+        </remarks>
         <exception cref="T:System.NotImplementedException">A derived class must override this method.</exception>
-        <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is over a different curve than this key.</exception>
+        <exception cref="T:System.ArgumentException">The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.
+</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyMaterial">
@@ -483,16 +551,28 @@
       </Parameters>
       <Docs>
         <param name="otherPartyPublicKey">The other party's public key.</param>
-        <summary>Derives bytes that can be used as a key, given another party's public key.</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
+        <summary>When implemented in a derived class, performs a key derivation on the shared secret.</summary>
+        <returns>The result of the key derivation function, using the shared secret as an input.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
-## Remarks  
- For more information about public keys, see the <xref:System.Security.Cryptography.ECDiffieHellmanPublicKey> class.  
-  
+## Remarks
+
+The default behavior of this method is equivalent to calling <xref:System.Security.Cryptography.ECDiffieHellman.DeriveKeyFromHash%2A> specifying SHA-256 as the hash algorithm with no prepend or append values.
+Some implementations allow the behavior of this method to be changed,
+and callers are advised to call whichever method explicitly says it performs the key derivation they need.
+
  ]]></format>
         </remarks>
+        <exception cref="T:System.ArgumentException">
+          The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyTls">
@@ -527,16 +607,37 @@
         <param name="otherPartyPublicKey">The other party's public key.</param>
         <param name="prfLabel">The ASCII-encoded PRF label.</param>
         <param name="prfSeed">The 64-byte PRF seed.</param>
-        <summary>When implemented in a derived class, derives bytes that can be used as a key using a Transport Layer Security (TLS) Pseudo-Random Function (PRF) derivation algorithm.</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
-        <remarks>To be added.</remarks>
+        <summary>When implemented in a derived class, performs key derivation using the TLS (Transport Layer Security) 1.1 PRF (Pseudo-Random Function).</summary>
+        <returns>The first 48 bytes from the TLS 1.1 PRF, using the shared secret as the key.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+This method internally performs the Elliptic Curve Diffie-Hellman key agreement to produce the shared secret (`z`).
+
+The return value of this method is a 48 byte output of the TLS 1.1 PRF (Pseudo-Random Function),
+`PRF(z, prfLabel, prfSeed)`.
+
+For more information, see [IETF RFC 4346, section 5](https://tools.ietf.org/html/rfc4346#section-5).
+
+]]></format>
+        </remarks>
         <exception cref="T:System.NotImplementedException">A derived class must override this method.</exception>
         <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is over a different curve than this key.</exception>
+          The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.</exception>
         <exception cref="T:System.ArgumentNullException">
-          <paramref name="prfLabel" /> or <paramref name="prfSeed" /> is <see langword="null" />.</exception>
+            <paramref name="otherPartyPublicKey"/>, <paramref name="prfLabel" /> or <paramref name="prfSeed" /> is <see langword="null" />.</exception>
         <exception cref="T:System.Security.Cryptography.CryptographicException">
-          <paramref name="prfSeed" /> is not exactly 64 bytes in length.</exception>
+          <paramref name="prfSeed" /> is not exactly 64 bytes in length.
+
+-or-
+
+The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="ExportECPrivateKey">
@@ -757,8 +858,10 @@
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- This method only supports the binary (BER/CER/DER) encoding of ECPrivateKey.
- If the value is Base64-encoded or in the PEM text format, the caller must Base64-decode the contents before calling this method.
+
+This method only supports the binary (BER/CER/DER) encoding of ECPrivateKey.
+If the value is Base64-encoded or in the PEM text format, the caller must Base64-decode the contents before calling this method.
+
  ]]></format>
         </remarks>
         <exception cref="T:System.Security.Cryptography.CryptographicException">The contents of <paramref name="source" /> do not represent an ASN.1-BER-encoded PKCS#8 ECPrivateKey structure.
@@ -803,11 +906,13 @@ The key import failed.
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
-## Remarks  
+## Remarks
+
  The password bytes are passed directly into the Key Derivation Function (KDF) used by the algorithm indicated by the EncryptedPrivateKeyInfo contents.
  This enables compatibility with other systems which use a text encoding other than UTF-8 when processing passwords with PBKDF2 (Password-Based Key Derivation Function 2).
  This method only supports the binary (BER/CER/DER) encoding of EncryptedPrivateKeyInfo.
  If the value is Base64-encoded or in the PEM text format, the caller must Base64-decode the contents before calling this method.
+
  ]]></format>
         </remarks>
         <exception cref="T:System.Security.Cryptography.CryptographicException">The password is incorrect.
@@ -830,8 +935,7 @@ The contents of <paramref name="source" /> represent the key in a format that is
 
 -or-
 
-The algorithm-specific key import failed.
-</exception>
+The algorithm-specific key import failed.</exception>
       </Docs>
     </Member>
     <Member MemberName="ImportEncryptedPkcs8PrivateKey">
@@ -872,6 +976,7 @@ The algorithm-specific key import failed.
  When the contents of `source` indicate an algorithm that uses PBKDF1 (Password-Based Key Derivation Function 1) or PBKDF2 (Password-Based Key Derivation Function 2), the password is converted to bytes via the UTF-8 encoding.
  This method only supports the binary (BER/CER/DER) encoding of EncryptedPrivateKeyInfo.
  If the value is Base64-encoded or in the PEM text format, the caller must Base64-decode the contents before calling this method.
+
  ]]></format>
         </remarks>
         <exception cref="T:System.Security.Cryptography.CryptographicException">The password is incorrect.
@@ -890,8 +995,7 @@ The contents of <paramref name="source" /> represent the key in a format that is
 
 -or-
 
-The algorithm-specific key import failed.
-</exception>
+The algorithm-specific key import failed.</exception>
       </Docs>
     </Member>
     <Member MemberName="ImportParameters">
@@ -973,6 +1077,7 @@ The algorithm-specific key import failed.
 ## Remarks  
  This method only supports the binary (BER/CER/DER) encoding of PrivateKeyInfo.
  If the value is Base64-encoded or in the PEM text format, the caller must Base64-decode the contents before calling this method.
+
  ]]></format>
         </remarks>
         <exception cref="T:System.Security.Cryptography.CryptographicException">The contents of <paramref name="source" /> do not represent an ASN.1-BER-encoded PKCS#8 PrivateKeyInfo structure.
@@ -987,8 +1092,7 @@ The contents of <paramref name="source" /> represent the key in a format that is
 
 -or-
 
-The algorithm-specific key import failed.
-</exception>
+The algorithm-specific key import failed.</exception>
       </Docs>
     </Member>
     <Member MemberName="ImportSubjectPublicKeyInfo">
@@ -1026,6 +1130,7 @@ The algorithm-specific key import failed.
 ## Remarks  
  This method only supports the binary (DER) encoding of SubjectPublicKeyInfo.
  If the value is Base64-encoded or in the PEM text format, the caller must Base64-decode the contents before calling this method.
+
  ]]></format>
         </remarks>
         <exception cref="T:System.Security.Cryptography.CryptographicException">The contents of <paramref name="source" /> do not represent an ASN.1-DER-encoded X.509 SubjectPublicKeyInfo structure.
@@ -1040,8 +1145,7 @@ The contents of <paramref name="source" /> represent the key in a format that is
 
 -or-
 
-The algorithm-specific key import failed.
-</exception>
+The algorithm-specific key import failed.</exception>
       </Docs>
     </Member>
     <Member MemberName="KeyExchangeAlgorithm">
@@ -1263,14 +1367,14 @@ The algorithm-specific key import failed.
 ## Remarks  
  The password bytes are passed directly into the Key Derivation Function (KDF) used by the algorithm indicated by `pbeParameters`.
  This enables compatibility with other systems which use a text encoding other than UTF-8 when processing passwords with PBKDF2 (Password-Based Key Derivation Function 2).
+
  ]]></format>
         </remarks>
         <exception cref="T:System.Security.Cryptography.CryptographicException">The key could not be exported.
 
 -or-
 
-<paramref name="pbeParameters" /> indicates that <see cref="F:System.Security.Cryptography.PbeEncryptionAlgorithm.TripleDes3KeyPkcs12" /> should be used, which requires <see cref="T:System.Char" />-based passwords.
-</exception>
+<paramref name="pbeParameters" /> indicates that <see cref="F:System.Security.Cryptography.PbeEncryptionAlgorithm.TripleDes3KeyPkcs12" /> should be used, which requires <see cref="T:System.Char" />-based passwords.</exception>
         <altmember cref="Overload:System.Security.Cryptography.AsymmetricAlgorithm.ExportEncryptedPkcs8PrivateKey" />
       </Docs>
     </Member>
@@ -1313,6 +1417,7 @@ The algorithm-specific key import failed.
   
 ## Remarks  
  When `pbeParameters` indicates an algorithm that uses PBKDF2 (Password-Based Key Derivation Function 2), the password is converted to bytes via the UTF-8 encoding.
+
  ]]></format>
         </remarks>
         <exception cref="T:System.Security.Cryptography.CryptographicException">The key could not be exported.</exception>
diff --git a/xml/System.Security.Cryptography/ECDiffieHellmanCng.xml b/xml/System.Security.Cryptography/ECDiffieHellmanCng.xml
index 0477b5b0550..f5482b53bd7 100644
--- a/xml/System.Security.Cryptography/ECDiffieHellmanCng.xml
+++ b/xml/System.Security.Cryptography/ECDiffieHellmanCng.xml
@@ -224,7 +224,7 @@
         <AssemblyVersion>4.0.0.0</AssemblyVersion>
       </AssemblyInfo>
       <Docs>
-        <summary>Derives bytes that can be used as a key using a hash function .</summary>
+        <summary>Performs key derivation using a specified hash algorithm.</summary>
       </Docs>
     </MemberGroup>
     <Member MemberName="DeriveKeyFromHash">
@@ -260,28 +260,26 @@
       </Parameters>
       <Docs>
         <param name="otherPartyPublicKey">The other party's public key.</param>
-        <param name="hashAlgorithm">The hash algorithm  to use to derive the key material.</param>
+        <param name="hashAlgorithm">The hash algorithm to use to derive the key material.</param>
         <param name="secretPrepend">A value to prepend to the derived secret before hashing.</param>
         <param name="secretAppend">A value to append to the derived secret before hashing.</param>
-        <summary>Derives bytes that can be used as a key using a hash function, given another party's public key, hash algorithm's name, a prepend value and an append value.</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
-        <remarks>
-          <format type="text/markdown"><![CDATA[  
-  
-## Remarks  
- If the value of `secretPrepend` or `secretAppend` is `null`, they are treated as empty arrays.  
-  
- ]]></format>
-        </remarks>
+        <summary>Performs key derivation using a specified hash algorithm with optional prepended or appended data.</summary>
+        <returns>The hash of the shared secret after prepending or appending data as requested.</returns>
+        <remarks>To be added.</remarks>
+        <exception cref="T:System.NotImplementedException">A derived class must override this method.</exception>
+        <exception cref="T:System.ArgumentException">The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.
+</exception>
         <exception cref="T:System.ArgumentNullException">
-          <paramref name="otherPartyPublicKey" /> is <see langword="null" />.</exception>
-        <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is not an ECDH key, or it is not the correct size.  
-  
- -or-  
-  
- <paramref name="hashAlgorithm" />.<see cref="P:System.Security.Cryptography.HashAlgorithmName.Name" /> is <see langword="null" /> or <see cref="F:System.String.Empty" />.</exception>
-        <exception cref="T:System.Security.Cryptography.CryptographicException">All other errors.</exception>
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="DeriveKeyFromHmac">
@@ -331,25 +329,21 @@
         <param name="hmacKey">The key for the HMAC.</param>
         <param name="secretPrepend">A value to prepend to the derived secret before hashing.</param>
         <param name="secretAppend">A value to append to the derived secret before hashing.</param>
-        <summary>Derives bytes that can be used as a key using a Hash-based Message Authentication Code (HMAC).</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
-        <remarks>
-          <format type="text/markdown"><![CDATA[  
-  
-## Remarks  
- If the value of `secretPrepend` or `secretAppend` is `null`, they are treated as empty arrays. If the value of `hmacKey` is `null`, the result of the Elliptic Curve Diffie-Hellman (ECDH) algorithm will be used as the HMAC key.  
-  
- ]]></format>
-        </remarks>
+        <summary>Performs key derivation using a specified HMAC (Hash-based Message Authentication Code) algorithm with optional prepended or appended data.</summary>
+        <returns>The HMAC of the shared secret after prepending or appending data as requested.</returns>
+        <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentException">The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.</exception>
         <exception cref="T:System.ArgumentNullException">
-          <paramref name="otherPartyPublicKey" /> is <see langword="null" />.</exception>
-        <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is not an ECDH key, or it is not the correct size.  
-  
- -or-  
-  
- <paramref name="hashAlgorithm" />.<see cref="P:System.Security.Cryptography.HashAlgorithmName.Name" /> is <see langword="null" /> or <see cref="F:System.String.Empty" />.</exception>
-        <exception cref="T:System.Security.Cryptography.CryptographicException">All other errors.</exception>
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="DeriveKeyMaterial">
@@ -483,27 +477,24 @@
         <param name="otherPartyPublicKey">The other party's public key.</param>
         <param name="prfLabel">The ASCII-encoded PRF label.</param>
         <param name="prfSeed">The 64-byte PRF seed.</param>
-        <summary>Derives bytes that can be used as a key using a Transport Layer Security (TLS) Pseudo-Random Function (PRF) derivation algorithm.</summary>
-        <returns>The key material from the key exchange with the other party's public key.</returns>
+        <summary>Performs key derivation using the TLS (Transport Layer Security) 1.1 PRF (Pseudo-Random Function).</summary>
+        <returns>The first 48 bytes from the TLS 1.1 PRF, using the shared secret as the key.</returns>
         <remarks>To be added.</remarks>
-        <exception cref="T:System.ArgumentNullException">
-          <paramref name="otherPartyPublicKey" /> is <see langword="null" />.  
-  
- -or-  
-  
- <paramref name="prfLabel" /> is <see langword="null" />.  
-  
- -or-  
-  
- <paramref name="prfSeed" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.NotImplementedException">A derived class must override this method.</exception>
         <exception cref="T:System.ArgumentException">
-          <paramref name="otherPartyPublicKey" /> is not an ECDH key, or it is not the correct size.</exception>
+          The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.</exception>
+        <exception cref="T:System.ArgumentNullException">
+            <paramref name="otherPartyPublicKey"/>, <paramref name="prfLabel" /> or <paramref name="prfSeed" /> is <see langword="null" />.</exception>
         <exception cref="T:System.Security.Cryptography.CryptographicException">
-          <paramref name="prfSeed" /> is not exactly 64 bytes in length.  
-  
- -or-  
-  
- All other cryptographic errors.</exception>
+          <paramref name="prfSeed" /> is not exactly 64 bytes in length.
+
+-or-
+
+The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="DeriveSecretAgreementHandle">
@@ -625,8 +616,9 @@
         <Parameter Name="disposing" Type="System.Boolean" />
       </Parameters>
       <Docs>
-        <param name="disposing">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="disposing">
+          <see langword="true"/> to release managed and unmanaged resources; <see langword="false"/> to release only unmanaged resources.</param>
+        <summary>Releases the resources used by the current instance of the <see cref="T:System.Security.Cryptography.ECDiffieHellmanCng"/> class.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -1043,9 +1035,22 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <summary>Gets or sets the size, in bits, of the key modulus used by the asymmetric algorithm.</summary>
+        <value>The size, in bits, of the key modulus used by the asymmetric algorithm.</value>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+Setting this property to its current value has no visible effect.
+Setting this property to a new legal value discards the current key, but defers creation of a new key until one is needed.
+
+Because key sizes do not uniquely identify elliptic curves, the use of the property setter is discouraged. To generate a new key on a specific curve, use the <xref:System.Security.Cryptography.ECDiffieHellmanCng.GenerateKey%2A> method.
+
+]]></format>
+        </remarks> 
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          <paramref name="value" /> is not permitted by <see cref="P:System.Security.Cryptography.ECDiffieHellmanCng.LegalKeySizes" />.</exception>
+        <altmember cref="M:System.Security.Cryptography.ECDiffieHellmanCng.GenerateKey(System.Security.Cryptography.ECCurve)" />
       </Docs>
     </Member>
     <Member MemberName="Label">
@@ -1109,9 +1114,25 @@
         <ReturnType>System.Security.Cryptography.KeySizes[]</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <summary>Gets the key sizes, in bits, that are supported by the <see cref="P:System.Security.Cryptography.ECDiffieHellmanCng.KeySize"/> property setter.</summary>
+        <value>An array that contains the key sizes supported by the <see cref="P:System.Security.Cryptography.ECDiffieHellmanCng.KeySize"/> property setter.</value>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+In Elliptic Curve Cryptography (ECC) the key size is not the only input into the key generation process,
+it is derived from the curve parameters for a specific elliptic curve.
+This property reports only three sizes for LegalKeySizes: 256, 384, and 521 bits.
+When the key size is used alone as a basis for key generation,
+the supported sizes map to the named curves secp256r1 (aka NIST P-256), secp384r1 (aka NIST P-384), and secp521r1 (aka NIST P-521).
+
+When executed on Windows 10, this class supports many additional named curves,
+but that is not reflected in this property.
+
+ ]]></format>
+        </remarks>
+        <altmember cref="M:System.Security.Cryptography.ECDiffieHellmanCng.GenerateKey(System.Security.Cryptography.ECCurve)" />
       </Docs>
     </Member>
     <Member MemberName="PublicKey">
@@ -1388,7 +1409,7 @@
   
 ## Remarks  
   
--   This value is used for key derivation if the <xref:System.Security.Cryptography.ECDiffieHellmanCng.KeyDerivationFunction%2A> property is set to <xref:System.Security.Cryptography.ECDiffieHellmanKeyDerivationFunction.Hmac>. By default, the value is `false`.  
+This value is used for key derivation if the <xref:System.Security.Cryptography.ECDiffieHellmanCng.KeyDerivationFunction%2A> property is set to <xref:System.Security.Cryptography.ECDiffieHellmanKeyDerivationFunction.Hmac>. By default, the value is `false`.  
   
  ]]></format>
         </remarks>
diff --git a/xml/System.Security.Cryptography/ECDiffieHellmanOpenSsl.xml b/xml/System.Security.Cryptography/ECDiffieHellmanOpenSsl.xml
index d1c490cfa71..f0481063d4f 100644
--- a/xml/System.Security.Cryptography/ECDiffieHellmanOpenSsl.xml
+++ b/xml/System.Security.Cryptography/ECDiffieHellmanOpenSsl.xml
@@ -15,8 +15,16 @@
   </Base>
   <Interfaces />
   <Docs>
-    <summary>To be added.</summary>
-    <remarks>To be added.</remarks>
+    <summary>Provides an implementation of the Elliptic Curve Diffie-Hellman (ECDH) algorithm backed by OpenSSL.</summary>
+    <remarks>
+      <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+This class should only be used directly when doing platform interop with the system OpenSSL library. When platform interop is not needed, you should use the <xref:System.Security.Cryptography.ECDiffieHellman.Create%2A?displayProperty=nameWithType> factory methods instead of a specific derived implementation.
+
+ ]]></format>
+   </remarks>
   </Docs>
   <Members>
     <Member MemberName=".ctor">
@@ -33,8 +41,18 @@
       </AssemblyInfo>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <summary>Initializes a new instance of the <see cref="T:System.Security.Cryptography.ECDiffieHellmanOpenSsl" /> class with a default curve of NIST P-521/secp521r1.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+This constructor does not generate a new public/private keypair immediately, it just sets the size which will be used to generate a key when one is needed.
+If key is loaded via the <xref:System.Security.Cryptography.ECDiffieHellmanOpenSsl.ImportParameters%2A> method, or other key import method, the key size from this constructor has no meaning.
+
+ ]]></format>
+        </remarks>
+        <altmember cref="M:System.Security.Cryptography.ECDiffieHellman.Create" />
       </Docs>
     </Member>
     <Member MemberName=".ctor">
@@ -54,9 +72,27 @@
         <Parameter Name="keySize" Type="System.Int32" />
       </Parameters>
       <Docs>
-        <param name="keySize">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="keySize">The size of the key to generate, when a key is needed.</param>
+        <summary>Initializes a new instance of the <see cref="T:System.Security.Cryptography.ECDiffieHellmanOpenSsl" /> class defaulting to the NIST prime curve of the specified size.</summary>
+        <remarks>
+          <format type="text/markdown">
+  <![CDATA[  
+  
+## Remarks  
+
+Only three key sizes are supported by this constructor: 256 (NIST P-256/secp256r1), 384 (NIST P-384/secp384r1), and 521 (NIST P-521/secp521r1).
+To generate keys For any other curve, use the <xref:System.Security.Cryptography.ECDiffieHellmanOpenSsl.%23ctor(System.Security.Cryptography.ECCurve)> constructor
+or the <xref:System.Security.Cryptography.ECDiffieHellmanOpenSsl.GenerateKey(System.Security.Cryptography.ECCurve)> method.
+
+This constructor does not generate a new public/private keypair immediately, it just sets the size which will be used to generate a key when one is needed.
+If key is loaded via the <xref:System.Security.Cryptography.ECDiffieHellmanOpenSsl.ImportParameters%2A> method, or other key import method, the key size from this constructor has no meaning.
+
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The <paramref name="keySize" /> value is not supported by this implementation.</exception>
+        <altmember cref="M:System.Security.Cryptography.ECDiffieHellman.Create" />
+        <altmember cref="M:System.Security.Cryptography.ECDiffieHellmanOpenSsl.#ctor(System.Security.Cryptography.ECCurve)" />
+        <altmember cref="M:System.Security.Cryptography.ECDiffieHellmanOpenSsl.GenerateKey(System.Security.Cryptography.ECCurve)" />
       </Docs>
     </Member>
     <Member MemberName=".ctor">
@@ -76,9 +112,24 @@
         <Parameter Name="handle" Type="System.IntPtr" />
       </Parameters>
       <Docs>
-        <param name="handle">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="handle">The OpenSSL <c>EC_KEY*</c> value to use as the key.</param>
+        <summary>Initializes a new instance of the <see cref="T:System.Security.Cryptography.ECDiffieHellmanOpenSsl" /> class from an existing OpenSSL key represented as an <c>EC_KEY*</c>.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+> [!IMPORTANT]
+> OpenSSL supports multiple library versions being loaded within the same process.
+> Before calling this constructor verify your pointer value came from the same version of OpenSSL that this class uses, see <xref:System.Security.Cryptography.SafeEvpPKeyHandle.OpenSslVersion> for more information.
+
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="handle" /> is <see cref="F:System.IntPtr.Zero"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          <paramref name="handle"/> is not a valid <c>EC_KEY*</c>.</exception>
+        <altmember cref="P:System.Security.Cryptography.SafeEvpPKeyHandle.OpenSslVersion" />
       </Docs>
     </Member>
     <Member MemberName=".ctor">
@@ -98,9 +149,12 @@
         <Parameter Name="curve" Type="System.Security.Cryptography.ECCurve" />
       </Parameters>
       <Docs>
-        <param name="curve">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="curve">The curve used to generate an ephemeral public/private key pair.</param>
+        <summary>Initializes a new instance of the <see cref="T:System.Security.Cryptography.ECDiffieHellmanOpenSsl" /> class and generates a new key on the specified curve.</summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          <paramref name="curve" /> does not validate.</exception>
+        <altmember cref="M:System.Security.Cryptography.ECCurve.Validate"/>
       </Docs>
     </Member>
     <Member MemberName=".ctor">
@@ -120,9 +174,25 @@
         <Parameter Name="pkeyHandle" Type="System.Security.Cryptography.SafeEvpPKeyHandle" />
       </Parameters>
       <Docs>
-        <param name="pkeyHandle">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="pkeyHandle">The OpenSSL <c>EVP_PKEY*</c> value to use as the key, represented as a <see cref="T:System.Security.Cryptography.SafeEvpPKeyHandle" />.</param>
+        <summary>Initializes a new instance of the <see cref="T:System.Security.Cryptography.ECDiffieHellmanOpenSsl" /> class from an existing OpenSSL key represented as an <c>EVP_PKEY*</c>.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+> [!IMPORTANT]
+> OpenSSL supports multiple library versions being loaded within the same process.
+> Before calling this constructor, verify your pointer value came from the same version of OpenSSL that this class uses.
+> For more information, see <xref:System.Security.Cryptography.SafeEvpPKeyHandle.OpenSslVersion>.
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="pkeyHandle" /> represents an invalid handle.</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="pkeyHandle" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          <paramref name="pkeyHandle" /> does not represent a elliptic curve (EC) key.</exception>
+        <seealso cref="P:System.Security.Cryptography.SafeEvpPKeyValue.OpenSslVersion" />
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyFromHash">
@@ -148,13 +218,27 @@
         <Parameter Name="secretAppend" Type="System.Byte[]" />
       </Parameters>
       <Docs>
-        <param name="otherPartyPublicKey">To be added.</param>
-        <param name="hashAlgorithm">To be added.</param>
-        <param name="secretPrepend">To be added.</param>
-        <param name="secretAppend">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="otherPartyPublicKey">The other party's public key.</param>
+        <param name="hashAlgorithm">The hash algorithm to use to derive the key material.</param>
+        <param name="secretPrepend">A value to prepend to the derived secret before hashing.</param>
+        <param name="secretAppend">A value to append to the derived secret before hashing.</param>
+        <summary>Performs key derivation using a specified hash algorithm with optional prepended or appended data.</summary>
+        <returns>The hash of the shared secret after prepending or appending data as requested.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentException">
+          The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyFromHmac">
@@ -181,14 +265,28 @@
         <Parameter Name="secretAppend" Type="System.Byte[]" />
       </Parameters>
       <Docs>
-        <param name="otherPartyPublicKey">To be added.</param>
-        <param name="hashAlgorithm">To be added.</param>
-        <param name="hmacKey">To be added.</param>
-        <param name="secretPrepend">To be added.</param>
-        <param name="secretAppend">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="otherPartyPublicKey">The other party's public key.</param>
+        <param name="hashAlgorithm">The hash algorithm to use to derive the key material.</param>
+        <param name="hmacKey">The key for the HMAC.</param>
+        <param name="secretPrepend">A value to prepend to the derived secret before hashing.</param>
+        <param name="secretAppend">A value to append to the derived secret before hashing.</param>
+        <summary>Performs key derivation using a specified HMAC (Hash-based Message Authentication Code) algorithm with optional prepended or appended data.</summary>
+        <returns>The HMAC of the shared secret after prepending or appending data as requested.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentException">
+          The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.
+
+-or-
+
+The <paramref name="hashAlgorithm"/> parameter does not specify a hash.</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyMaterial">
@@ -211,10 +309,18 @@
         <Parameter Name="otherPartyPublicKey" Type="System.Security.Cryptography.ECDiffieHellmanPublicKey" />
       </Parameters>
       <Docs>
-        <param name="otherPartyPublicKey">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="otherPartyPublicKey">The other party's public key.</param>
+        <summary>Performs a key derivation on the shared secret.</summary>
+        <returns>The SHA-256 hash of the shared secret.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentException">The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.</exception>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="otherPartyPublicKey" /> is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DeriveKeyTls">
@@ -239,12 +345,26 @@
         <Parameter Name="prfSeed" Type="System.Byte[]" />
       </Parameters>
       <Docs>
-        <param name="otherPartyPublicKey">To be added.</param>
-        <param name="prfLabel">To be added.</param>
-        <param name="prfSeed">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="otherPartyPublicKey">The other party's public key.</param>
+        <param name="prfLabel">The ASCII-encoded PRF label.</param>
+        <param name="prfSeed">The 64-byte PRF seed.</param>
+        <summary>Performs key derivation using the TLS (Transport Layer Security) 1.1 PRF (Pseudo-Random Function).</summary>
+        <returns>The first 48 bytes from the TLS 1.1 PRF, using the shared secret as the key.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.NotImplementedException">A derived class must override this method.</exception>
+        <exception cref="T:System.ArgumentException">The curve used by <paramref name="otherPartyPublicKey" /> has a different size than the curve from this key.</exception>
+        <exception cref="T:System.ArgumentNullException">
+            <paramref name="otherPartyPublicKey"/>, <paramref name="prfLabel" /> or <paramref name="prfSeed" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          <paramref name="prfSeed" /> is not exactly 64 bytes in length.
+
+-or-
+
+The curve used by <paramref name="otherPartyPublicKey" /> is different than the curve from this key.
+
+-or-
+
+This instance represents only a public key.</exception>
       </Docs>
     </Member>
     <Member MemberName="DuplicateKeyHandle">
@@ -265,9 +385,18 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <summary>Gets a <see cref="T:System.Security.Cryptography.SafeEvpPKeyHandle"/> representation of the cryptographic key.</summary>
+        <returns>A <see cref="T:System.Security.Cryptography.SafeEvpPKeyHandle"/> representation of the cryptographic key.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks
+
+Each call to this method produces a new <xref:System.Security.Cryptography.SafeEvpPKeyHandle> object with its own lifetime.
+The objects returned by this method can safely be used even after this <xref:System.Security.Cryptography.ECDiffieHellmanOpenSsl> instance has been disposed.
+
+]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="ExportExplicitParameters">
@@ -290,10 +419,12 @@
         <Parameter Name="includePrivateParameters" Type="System.Boolean" />
       </Parameters>
       <Docs>
-        <param name="includePrivateParameters">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="includePrivateParameters">
+          <see langword="true" /> to include private parameters; otherwise, <see langword="false" />.</param>
+        <summary>Exports either the public or the public and private key information using the explicit curve form from the current key to an <see cref="T:System.Security.Cryptography.ECParameters" /> structure so that it can be passed to the <see cref="M:System.Security.Cryptography.ECDiffieHellman.ImportParameters(System.Security.Cryptography.ECParameters)" /> method.</summary>
+        <returns>An object that represents the point on the curve for this key, using the explicit curve format.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The method cannot obtain curve values.</exception>
       </Docs>
     </Member>
     <Member MemberName="ExportParameters">
@@ -316,10 +447,19 @@
         <Parameter Name="includePrivateParameters" Type="System.Boolean" />
       </Parameters>
       <Docs>
-        <param name="includePrivateParameters">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="includePrivateParameters">
+          <see langword="true" /> to include private parameters; otherwise, <see langword="false" />.</param>
+        <summary>Exports the key used by the <see cref="T:System.Security.Cryptography.ECCurve" /> object into an <see cref="T:System.Security.Cryptography.ECParameters" /> object.</summary>
+        <returns>The key and named curve parameters used by the <see cref="T:System.Security.Cryptography.ECCurve" /> object.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ If the key was created as a named curve, the <xref:System.Security.Cryptography.ECParameters.Curve?displayProperty=nameWithType> field contains named curve parameters; otherwise,  it contains explicit parameters.  
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The method cannot obtain curve values.</exception>
       </Docs>
     </Member>
     <Member MemberName="GenerateKey">
@@ -342,9 +482,18 @@
         <Parameter Name="curve" Type="System.Security.Cryptography.ECCurve" />
       </Parameters>
       <Docs>
-        <param name="curve">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="curve">The curve used to generate an ephemeral public/private key pair.</param>
+        <summary>Generates a new ephemeral public/private key pair for the specified curve.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ `curve` must validate (that is, it must return true when passed to the <xref:System.Security.Cryptography.ECCurve.Validate?displayProperty=nameWithType> method) and must not be implicit.  
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          <paramref name="curve" /> does not validate.</exception>
       </Docs>
     </Member>
     <Member MemberName="ImportParameters">
@@ -367,9 +516,22 @@
         <Parameter Name="parameters" Type="System.Security.Cryptography.ECParameters" />
       </Parameters>
       <Docs>
-        <param name="parameters">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="parameters">The curve's parameters to import.</param>
+        <summary>Imports the specified parameters for an <see cref="T:System.Security.Cryptography.ECCurve" /> object as a key into the current instance.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ The <xref:System.Security.Cryptography.ECDiffieHellmanCng.ImportParameters%2A> method replaces the existing key that this object is working with by creating a         new <xref:System.Security.Cryptography.CngKey> object. If `parameters` contains only the <xref:System.Security.Cryptography.ECParameters.Q> field, then only a public key is imported.         If `parameters` also contains <xref:System.Security.Cryptography.ECParameters.D>, then a full key pair is be imported. The `parameter` <xref:System.Security.Cryptography.ECParameters.Curve> value specifies the type of the curve to import.  
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">
+          <paramref name="parameters" /> does not validate.</exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="parameters" /> references a curve that cannot be imported.</exception>
+        <exception cref="T:System.PlatformNotSupportedException">
+          <paramref name="parameters" /> references a curve that is not supported by this platform.</exception>
       </Docs>
     </Member>
     <Member MemberName="PublicKey">
@@ -389,8 +551,8 @@
         <ReturnType>System.Security.Cryptography.ECDiffieHellmanPublicKey</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the public key that can be used by another <see cref="T:System.Security.Cryptography.ECDiffieHellman" /> object to generate a shared secret agreement.</summary>
+        <value>The public key that is associated with this instance of the <see cref="T:System.Security.Cryptography.ECDiffieHellmanOpenSsl" /> object.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>