diff --git a/SabreTools.Models/ASN1/ASN1Type.cs b/SabreTools.Models/ASN1/ASN1Type.cs
new file mode 100644
index 0000000..762b666
--- /dev/null
+++ b/SabreTools.Models/ASN1/ASN1Type.cs
@@ -0,0 +1,58 @@
+using System;
+
+namespace SabreTools.Models.ASN1
+{
+    /// <summary>
+    /// ASN.1 type indicators
+    /// </summary>
+    [Flags]
+    public enum ASN1Type : byte
+    {
+        #region Types
+
+        V_ASN1_EOC = 0x00,
+        V_ASN1_BOOLEAN = 0x01,
+        V_ASN1_INTEGER = 0x02,
+        V_ASN1_BIT_STRING = 0x03,
+        V_ASN1_OCTET_STRING = 0x04,
+        V_ASN1_NULL = 0x05,
+        V_ASN1_OBJECT = 0x06,
+        V_ASN1_OBJECT_DESCRIPTOR = 0x07,
+        V_ASN1_EXTERNAL = 0x08,
+        V_ASN1_REAL = 0x09,
+        V_ASN1_ENUMERATED = 0x0A,
+        V_ASN1_UTF8STRING = 0x0C,
+        V_ASN1_SEQUENCE = 0x10,
+        V_ASN1_SET = 0x11,
+        V_ASN1_NUMERICSTRING = 0x12,
+        V_ASN1_PRINTABLESTRING = 0x13,
+        V_ASN1_T61STRING = 0x14,
+        V_ASN1_TELETEXSTRING = 0x14,
+        V_ASN1_VIDEOTEXSTRING = 0x15,
+        V_ASN1_IA5STRING = 0x16,
+        V_ASN1_UTCTIME = 0x17,
+        V_ASN1_GENERALIZEDTIME = 0x18,
+        V_ASN1_GRAPHICSTRING = 0x19,
+        V_ASN1_ISO64STRING = 0x1A,
+        V_ASN1_VISIBLESTRING = 0x1A,
+        V_ASN1_GENERALSTRING = 0x1B,
+        V_ASN1_UNIVERSALSTRING = 0x1C,
+        V_ASN1_BMPSTRING = 0x1E,
+
+        #endregion
+
+        #region Modifiers
+
+        // Commented out because it is the default
+        // and can interfere with V_ASN1_EOC
+        // V_ASN1_UNIVERSAL = 0x00,
+
+        V_ASN1_PRIMITIVE_TAG = 0x1F,
+        V_ASN1_CONSTRUCTED = 0x20,
+        V_ASN1_APPLICATION = 0x40,
+        V_ASN1_CONTEXT_SPECIFIC = 0x80,
+        V_ASN1_PRIVATE = 0xC0,
+
+        #endregion
+    }
+}
diff --git a/SabreTools.Models/ASN1/TypeLengthValue.cs b/SabreTools.Models/ASN1/TypeLengthValue.cs
new file mode 100644
index 0000000..29c188b
--- /dev/null
+++ b/SabreTools.Models/ASN1/TypeLengthValue.cs
@@ -0,0 +1,23 @@
+namespace SabreTools.Models.ASN1
+{
+    /// <summary>
+    /// ASN.1 type/length/value class that all types are based on
+    /// </summary>
+    public class TypeLengthValue
+    {
+        /// <summary>
+        /// The ASN.1 type
+        /// </summary>
+        public ASN1Type Type { get; set; }
+
+        /// <summary>
+        /// Length of the value
+        /// </summary>
+        public ulong Length { get; set; }
+
+        /// <summary>
+        /// Generic value associated with <see cref="Type"/>
+        /// </summary>
+        public object? Value { get; set; }
+    }
+}