/// <summary>
/// Декодируем из байтового массива в формате ASN1
/// </summary>
/// <param name="baAsn1">Байтовый массив в формате ASN1</param>
/// <returns>Текстовое представление пакета ASN1</returns>
public string DecodeFromAsn1(byte[] baAsn1)
{
var memoryStream = new MemoryStream(baAsn1);
using (var berReader = new BerReader(memoryStream))
{
//Формируем маркант
try
{
var node = berReader.ReadToEnd().ChildNodes[0];
string result = "";
foreach (var childNode in node.ChildNodes)
{
result = berReader.PrintStructure(childNode, result, 1, true);
}
Version = (int)node.ChildNodes[0].ReadContentAsBigInteger();
SessionKey = node.ChildNodes[1].RawValue;
IV = node.ChildNodes[2].RawValue;
PublicKey = node.ChildNodes[3].RawValue;
return(result);
}
catch (Exception e)
{
throw new Exception("Invalid markant format", e);
}
}
}
/// <summary>
/// Load ASN.1 object in form of a stream, parse it and display its structure.
/// </summary>
/// <param name="asn1Content">ASN.1 object to parse.</param>
public void LoadContent(Stream asn1Content)
{
// clear any existing nodes
Nodes.Clear();
// use parser to get the structure
using (var reader = new BerReader(asn1Content))
{
var rootNode = new InternalNode();
try
{
// read whole object. This may fail if there is no valid ASN.1 object in the stream.
rootNode = reader.ReadToEnd(ReadContent);
}
catch (Exception ex)
{
// something went wrong when reading file. Possibly it was not an ASN.1 object.
Trace.WriteLine(String.Format("Parsing exception: {0}", ex));
var safetyNode = new Asn1TreeNode(null, "Invalid ASN.1 structure.");
Nodes.Add(safetyNode);
}
// reader does not parse encapsulated data. Do it manually.
foreach (InternalNode internalNode in rootNode.ChildNodes)
{
// This will enrich list of nodes with additional nodes parsed out of values of Primitive ASN.1 nodes
if (EncapsulatedDataParsing)
{
ParseEncapsulatedData(internalNode);
}
// build tree from list of ASN.1 nodes
var rootTreeNode = new Asn1TreeNode(internalNode);
MakeTreeNode(rootTreeNode, internalNode, 1, EncapsulatedDataParsing);
Nodes.Add(rootTreeNode);
}
}
// expand tree
ExpandAll();
SelectedNode = Nodes[0];
}
/// <summary>
/// Method will parse value of given node for existing ASN.1 objects.
/// </summary>
/// <param name="innerNode">Node to parse.</param>
internal static void ParseEncapsulatedData(InternalNode innerNode)
{
if (innerNode.NodeType != Asn1NodeType.Primitive)
{
return;
}
if (innerNode.RawValue == null)
{
return; // nothing to parse
}
// for now, only BIT STRING or OCTET STRING may contain encapsulated data
if (innerNode.Identifier.Tag != Asn1Type.BitString && innerNode.Identifier.Tag != Asn1Type.OctetString)
{
return;
}
byte[] dataToParse = innerNode.RawValue;
if (innerNode.Identifier.Tag == Asn1Type.BitString)
{
dataToParse = innerNode.ReadContentAsBitString();
}
// Reader will close the stream when it is done parsing
var memStream = new MemoryStream(dataToParse);
using (var innerReader = new BerReader(memStream))
{
try
{
InternalNode innerRootNode = innerReader.ReadToEnd(true);
innerNode.ChildNodes.AddRange(innerRootNode.ChildNodes);
}
catch (Exception)
{
// nothing to do. Value of primitive node did not contain valid ASN.1 structure.
}
}
}
/// <summary>
/// Формирует строка со структурным представлением байтового массива в формате ASN1
/// </summary>
/// <param name="baAsn1">Байтовый массив в формате ASN1</param>
/// <returns>Строка с текстовым представлением байтового массива в формате ASN1</returns>
public static string PrintFromAsn1(byte[] baAsn1)
{
var memoryStream = new MemoryStream(baAsn1);
using (var berReader = new BerReader(memoryStream))
{
//Формируем текстовое представление марканта
try
{
var node = berReader.ReadToEnd().ChildNodes[0];
string result = "ASN1:";
foreach (var childNode in node.ChildNodes)
{
result = berReader.PrintStructure(childNode, result, 1, true);
}
return(result);
}
catch (Exception e)
{
throw new Exception("Invalid ASN format", e);
}
}
}
