diff --git a/xml/System.Security.Cryptography.Pkcs/Pkcs8PrivateKeyInfo.xml b/xml/System.Security.Cryptography.Pkcs/Pkcs8PrivateKeyInfo.xml
index dccd67a5792..bdb8bf46fc2 100644
--- a/xml/System.Security.Cryptography.Pkcs/Pkcs8PrivateKeyInfo.xml
+++ b/xml/System.Security.Cryptography.Pkcs/Pkcs8PrivateKeyInfo.xml
@@ -15,7 +15,7 @@
   </Base>
   <Interfaces />
   <Docs>
-    <summary>To be added.</summary>
+    <summary>Enables the inspection of and creation of PKCS#8 PrivateKeyInfo and EncryptedPrivateKeyInfo values. This class cannot be inherited.</summary>
     <remarks>To be added.</remarks>
   </Docs>
   <Members>
@@ -38,12 +38,31 @@
         <Parameter Name="skipCopies" Type="System.Boolean" />
       </Parameters>
       <Docs>
-        <param name="algorithmId">To be added.</param>
-        <param name="algorithmParameters">To be added.</param>
-        <param name="privateKey">To be added.</param>
-        <param name="skipCopies">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="algorithmId">The Object Identifier (OID) identifying the asymmetric algorithm this key is for.</param>
+        <param name="algorithmParameters">The BER-encoded algorithm parameters associated with this key, or <see langword="null"/> to omit algorithm parameters when encoding.</param>
+        <param name="privateKey">The algorithm-specific encoded private key.</param>
+        <param name="skipCopies"><see langword="true"/> to store <paramref name="algorithmParameters"/> and <paramref name="privateKey"/> without making a defensive copy; otherwise, <see langword="false"/>. The default is <see langword="false"/>.</param>
+        <summary>Initializes a new instance of the <see cref="T:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo"/> class.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+
+No validation is done on the `privateKey` parameter; not all algorithms require a BER-encoded value.
+
+The default behavior of this constructor is to make a defensive copy of both the `algorithmParameters` and the `privateKey` parameters.
+When the `skipCopies` parameter is `true`, this defensive copy is skipped.
+If the defensive copy is skipped and the contents of either `algorithmParameters` or `privateKey` change during the lifetime of the returned value or of any object produced by its
+methods or properties, then methods and properties on those objects may produce nonsense results or throw exceptions due to the corrupted state.
+Callers are therefore advised to only use a `true` value for the `skipCopies` parameter when they can be reasonably assured that the data will stay intact.
+    
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="algorithmId"/> parameter is <see langword="null"/>.</exception>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The <paramref name="algorithmParameters"/> parameter is not <see langword="null"/>, empty, or a single BER-encoded value.</exception>
+        <altmember cref="M:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.Create(System.Security.Cryptography.AsymmetricAlgorithm)"/>
+        <altmember cref="Overload:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.Decode"/>
+        <altmember cref="Overload:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.DecryptAndDecode"/>
       </Docs>
     </Member>
     <Member MemberName="AlgorithmId">
@@ -63,8 +82,8 @@
         <ReturnType>System.Security.Cryptography.Oid</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the Object Identifier (OID) value identifying the algorithm this key is for.</summary>
+        <value>The Object Identifier (OID) value identifying the algorithm this key is for.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -85,8 +104,8 @@
         <ReturnType>System.Nullable&lt;System.ReadOnlyMemory&lt;System.Byte&gt;&gt;</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets a memory value containing the BER-encoded algorithm parameters associated with this key.</summary>
+        <value>A memory value containing the BER-encoded algorithm parameters associated with this key, or <see langword="null"/> if no parameters were present.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -107,8 +126,8 @@
         <ReturnType>System.Security.Cryptography.CryptographicAttributeObjectCollection</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the modifiable collection of attributes for this private key.</summary>
+        <value>The modifiable collection of attributes to encode with the private key.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -132,10 +151,13 @@
         <Parameter Name="privateKey" Type="System.Security.Cryptography.AsymmetricAlgorithm" />
       </Parameters>
       <Docs>
-        <param name="privateKey">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="privateKey">The private key to represent in a PKCS#8 PrivateKeyInfo.</param>
+        <summary>Exports a specified key as a PKCS#8 PrivateKeyInfo and returns its decoded interpretation.</summary>
+        <returns>The decoded interpretation of the exported PKCS#8 PrivateKeyInfo.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="privateKey"/> parameter is <see langword="null"/>.</exception>
+        <altmember cref="M:System.Security.Cryptography.AsymmetricAlgorithm.ExportPkcs8PrivateKey"/>
+        <altmember cref="Overload:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.Decode"/>
       </Docs>
     </Member>
     <Member MemberName="Decode">
@@ -159,12 +181,24 @@
         <Parameter Name="skipCopy" Type="System.Boolean" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <param name="bytesRead">To be added.</param>
-        <param name="skipCopy">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="source">The data to interpret as a PKCS#8 PrivateKeyInfo value.</param>
+        <param name="bytesRead">When this method returns, contains a value that indicates the number of bytes read from <paramref name="source"/>. This parameter is treated as uninitialized.</param>
+        <param name="skipCopy"><see langword="true"/> to store <paramref name="source"/> without making a defensive copy; otherwise, <see langword="false"/>. The default is <see langword="false"/>.</param>
+        <summary>Reads the provided data as a PKCS#8 PrivateKeyInfo and returns an object view of the contents.</summary>
+        <returns>An object view of the contents decoded as a PKCS#8 PrivateKeyInfo.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks
+ The default behavior of this method is to make a defensive copy of the first `bytesConsumed` bytes from `source`.
+ When the `skipCopy` parameter is `true`, this defensive copy is skipped.
+ If the defensive copy is skipped and the contents of the first `bytesConsumed` bytes of `source` change during the lifetime of the returned value or of any object produced by its
+ methods or properties, then methods and properties on those objects may produce nonsense results or throw exceptions due to the corrupted state.
+ Callers are therefore advised to only use a `true` value for the `skipCopy` parameter when they can be reasonably assured that the data will stay intact.
+ 
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.Security.Cryptography.CryptographicException">The contents of the <paramref name="source"/> parameter were not successfully decoded as a PKCS#8 PrivateKeyInfo.</exception>
       </Docs>
     </Member>
     <Member MemberName="DecryptAndDecode">
@@ -189,13 +223,34 @@
         <Parameter Name="bytesRead" Type="System.Int32" RefType="out" />
       </Parameters>
       <Docs>
-        <param name="passwordBytes">To be added.</param>
-        <param name="source">To be added.</param>
-        <param name="bytesRead">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="passwordBytes">The bytes to use as a password when decrypting the key material.</param>
+        <param name="source">The data to read as a PKCS#8 EncryptedPrivateKeyInfo structure in the ASN.1-BER encoding.</param>
+        <param name="bytesRead">When this method returns, contains a value that indicates the number of bytes read from <paramref name="source"/>. This parameter is treated as uninitialized.</param>
+        <summary>Decrypts the provided data using the provided byte-based password and decodes the output into an object view of the PKCS#8 PrivateKeyInfo.</summary>
+        <returns>An object view of the contents decrypted decoded as a PKCS#8 PrivateKeyInfo.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## 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).
+
+ 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.
+
+-or-
+
+The contents of <paramref name="source"/> indicate the Key Derivation Function (KDF) to apply is the legacy PKCS#12 KDF, which requires <see cref="T:System.Char"/>-based passwords.
+
+-or-
+
+The contents of <paramref name="source"/> do not represent an ASN.1-BER-encoded PKCS#8 EncryptedPrivateKeyInfo structure.</exception>
       </Docs>
+      <altmember cref="M:System.Security.Cryptography.AsymmetricAlgorithm.ImportPkcs8PrivateKey"/>
     </Member>
     <Member MemberName="DecryptAndDecode">
       <MemberSignature Language="C#" Value="public static System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo DecryptAndDecode (ReadOnlySpan&lt;char&gt; password, ReadOnlyMemory&lt;byte&gt; source, out int bytesRead);" />
@@ -219,12 +274,23 @@
         <Parameter Name="bytesRead" Type="System.Int32" RefType="out" />
       </Parameters>
       <Docs>
-        <param name="password">To be added.</param>
-        <param name="source">To be added.</param>
-        <param name="bytesRead">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="password">The password to use when decrypting the key material.</param>
+        <param name="source">The bytes of a PKCS#8 EncryptedPrivateKeyInfo structure in the ASN.1-BER encoding.</param>
+        <param name="bytesRead">When this method returns, contains a value that indicates the number of bytes read from <paramref name="source"/>. This parameter is treated as uninitialized.</param>
+        <summary>Decrypts the provided data using the provided character-based password and decodes the output into an object view of the PKCS#8 PrivateKeyInfo.</summary>
+        <returns>An object view of the contents decrypted decoded as a PKCS#8 PrivateKeyInfo.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ 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>
+      <altmember cref="Overload:System.Security.Cryptography.AsymmetricAlgorithm.ImportEncryptedPkcs8PrivateKey"/>
       </Docs>
     </Member>
     <Member MemberName="Encode">
@@ -245,9 +311,10 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Encodes the property data of this instance as a PKCS#8 PrivateKeyInfo and returns the encoding as a byte array.</summary>
+        <returns>A byte array representing the encoded form of the PKCS#8 PrivateKeyInfo.</returns>
         <remarks>To be added.</remarks>
+        <altmember cref="Overload:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.TryEncode"/>
       </Docs>
     </Member>
     <Member MemberName="Encrypt">
@@ -270,11 +337,21 @@
         <Parameter Name="pbeParameters" Type="System.Security.Cryptography.PbeParameters" />
       </Parameters>
       <Docs>
-        <param name="passwordBytes">To be added.</param>
-        <param name="pbeParameters">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="passwordBytes">The bytes to use as a password when encrypting the key material.</param>
+        <param name="pbeParameters">The password-based encryption (PBE) parameters to use when encrypting the key material.</param>
+        <summary>Produces a PKCS#8 EncryptedPrivateKeyInfo from the property contents of this object after encrypting with the specified byte-based password and encryption parameters.</summary>
+        <returns>A byte array containing the encoded form of the PKCS#8 EncryptedPrivateKeyInfo.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## 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"><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.Pkcs.Pkcs8PrivateKeyInfo.TryEncrypt"/>
       </Docs>
     </Member>
     <Member MemberName="Encrypt">
@@ -297,11 +374,19 @@
         <Parameter Name="pbeParameters" Type="System.Security.Cryptography.PbeParameters" />
       </Parameters>
       <Docs>
-        <param name="password">To be added.</param>
-        <param name="pbeParameters">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="password">The password to use when encrypting the key material.</param>
+        <param name="pbeParameters">The password-based encryption (PBE) parameters to use when encrypting the key material.</param>
+        <summary>Produces a PKCS#8 EncryptedPrivateKeyInfo from the property contents of this object after encrypting with the specified character-based password and encryption parameters.</summary>
+        <returns>A byte array containing the encoded form of the PKCS#8 EncryptedPrivateKeyInfo.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## 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>
+        <altmember cref="Overload:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.TryEncrypt"/>
       </Docs>
     </Member>
     <Member MemberName="PrivateKeyBytes">
@@ -321,8 +406,8 @@
         <ReturnType>System.ReadOnlyMemory&lt;System.Byte&gt;</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets a memory value that represents the algorithm-specific encoded private key.</summary>
+        <value>A memory value that represents the algorithm-specific encoded private key.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -347,11 +432,12 @@
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" />
       </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 byte span to receive the PKCS#8 PrivateKeyInfo data.</param>
+        <param name="bytesWritten">When this method returns, contains a value that indicates the number of bytes written to <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to encode the property data of this instance as a PKCS#8 PrivateKeyInfo, writing the results into a provided buffer.</summary>
+        <returns><see langword="true"/> if <paramref name="destination"/> is big enough to receive the output; otherwise, <see langword="false"/>.</returns>
         <remarks>To be added.</remarks>
+        <altmember cref="M:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.Encode"/>
       </Docs>
     </Member>
     <Member MemberName="TryEncrypt">
@@ -376,13 +462,22 @@
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" />
       </Parameters>
       <Docs>
-        <param name="passwordBytes">To be added.</param>
-        <param name="pbeParameters">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>
-        <remarks>To be added.</remarks>
+        <param name="passwordBytes">The bytes to use as a password when encrypting the key material.</param>
+        <param name="pbeParameters">The password-based encryption (PBE) parameters to use when encrypting the key material.</param>
+        <param name="destination">The byte span to receive the PKCS#8 EncryptedPrivateKeyInfo data.</param>
+        <param name="bytesWritten">When this method returns, contains a value that indicates the number of bytes written to <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to produce a PKCS#8 EncryptedPrivateKeyInfo from the property contents of this object after encrypting with the specified byte-based password and encryption parameters, writing the results into a provided buffer.</summary>
+        <returns><see langword="true"/> if <paramref name="destination"/> is big enough to receive the output; otherwise, <see langword="false"/>.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## 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>
+        <altmember cref="Overload:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.Encrypt"/>
       </Docs>
     </Member>
     <Member MemberName="TryEncrypt">
@@ -407,14 +502,22 @@
         <Parameter Name="bytesWritten" Type="System.Int32" RefType="out" />
       </Parameters>
       <Docs>
-        <param name="password">To be added.</param>
-        <param name="pbeParameters">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>
-        <remarks>To be added.</remarks>
+        <param name="password">The password to use when encrypting the key material.</param>
+        <param name="pbeParameters">The password-based encryption (PBE) parameters to use when encrypting the key material.</param>
+        <param name="destination">The byte span to receive the PKCS#8 EncryptedPrivateKeyInfo data.</param>
+        <param name="bytesWritten">When this method returns, contains a value that indicates the number of bytes written to <paramref name="destination"/>. This parameter is treated as uninitialized.</param>
+        <summary>Attempts to produce a PKCS#8 EncryptedPrivateKeyInfo from the property contents of this object after encrypting with the specified character-based password and encryption parameters, writing the result into a provided buffer.</summary>
+        <returns><see langword="true"/> if <paramref name="destination"/> is big enough to receive the output; otherwise, <see langword="false"/>.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## 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>
+        <altmember cref="Overload:System.Security.Cryptography.Pkcs.Pkcs8PrivateKeyInfo.Encrypt"/>
       </Docs>
     </Member>
   </Members>
-</Type>
\ No newline at end of file
+</Type>