Add a couple missing extra field structures

SabreTools.Models/PKZIP/AesEncryptionStructure.cs

@@ -0,0 +1,33 @@
+namespace SabreTools.Models.PKZIP
+{
+    /// <summary>
+    /// WinZip AES encryption data
+    /// </summary>
+    /// <remarks>Header ID = 0x9901</remarks>
+    /// <see href="https://github.com/adamhathcock/sharpcompress/blob/master/src/SharpCompress/Common/Zip/Headers/LocalEntryHeaderExtraFactory.cs"/> 
+    public class AesEncryptionStructure : ExtensibleDataField
+    {
+        /// <summary>
+        /// Compression type
+        /// </summary>
+        /// <remarks>Values 0f 0x01 and 0x02 are accepted</remarks>
+        public ushort CompressionType { get; set; }
+
+        /// <summary>
+        /// Vendor ID
+        /// </summary>
+        /// <remarks>Should be 0x4541</remarks>
+        public ushort VendorID { get; set; }
+
+        /// <summary>
+        /// Unknown
+        /// </summary>
+        /// <remarks>This value is unreferenced</remarks>
+        public byte Unknown { get; set; }
+
+        /// <summary>
+        /// Compression method
+        /// </summary>
+        public CompressionMethod CompressionMethod { get; set; }
+    }
+}

SabreTools.Models/PKZIP/Enums.cs

@@ -1002,6 +1002,18 @@ namespace SabreTools.Models.PKZIP
         */
     }
 
+    [Flags]
+    public enum RecordedTimeFlag : byte
+    {
+        None = 0,
+
+        LastModified = 1,
+
+        LastAccessed = 2,
+
+        Created = 4,
+    }
+
     [Flags]
     public enum ZipItInternalSettings : ushort
     {

SabreTools.Models/PKZIP/ExtendedTimestampExtraField.cs

@@ -0,0 +1,33 @@
+namespace SabreTools.Models.PKZIP
+{
+    /// <summary>
+    /// The unix modified time, last access time, and creation time, if set
+    /// </summary>
+    /// <remarks>Header ID = 0x5455</remarks>
+    /// <see href="https://github.com/adamhathcock/sharpcompress/blob/master/src/SharpCompress/Common/Zip/Headers/LocalEntryHeaderExtraFactory.cs"/> 
+    public class ExtendedTimestampExtraField : ExtensibleDataField
+    {
+        /// <summary>
+        /// Indicates what tiemstamps are included
+        /// </summary>
+        public RecordedTimeFlag Flags { get; set; }
+
+        /// <summary>
+        /// Last modified time
+        /// </summary>
+        /// <remarks>Only available when <see cref="RecordedTimeFlag.LastModified"/> is set</remarks> 
+        public uint? LastModified { get; set; }
+
+        /// <summary>
+        /// Last accessed time
+        /// </summary>
+        /// <remarks>Only available when <see cref="RecordedTimeFlag.LastAccessed"/> is set</remarks> 
+        public uint? LastAccessed { get; set; }
+
+        /// <summary>
+        /// Created on time
+        /// </summary>
+        /// <remarks>Only available when <see cref="RecordedTimeFlag.Created"/> is set</remarks> 
+        public uint? CreatedOn { get; set; }
+    }
+}