/// <summary>
/// Decodes the object by PER.
/// </summary>
/// <param name="buffer">A buffer that contains a PER encoding result.</param>
/// <param name="aligned">Indicating whether the PER decoding is aligned.</param>
/// <remarks>Length is included.</remarks>
protected override void ValuePerDecode(IAsn1DecodingBuffer buffer, bool aligned = true)
{
ByteArrayValue = Asn1StandardProcedure.PerDecodeArray <byte>(buffer,
decodingBuffer =>
{
Asn1Integer ai = new Asn1Integer(null, 0, 15);
ai.PerDecode(buffer);
if (Constraint == null || Constraint.PermittedCharSet == null)
{
if (ai.Value == 0)
{
return((byte)' ');
}
else if (ai.Value >= 1 && ai.Value <= 10)
{
return((byte)((byte)'0' + ai.Value - 1));
}
else
{
throw new Asn1DecodingUnexpectedData(ExceptionMessages.DecodingUnexpectedData +
"Only 0~9 and SPACE are allowed in NumericString.");
}
}
else
{
int index = (int)ai.Value;
return((byte)CharSetInArray[(int)ai.Value]);
}
},
Constraint != null && Constraint.HasMinSize ? Constraint.MinSize : (long?)null, Constraint != null && Constraint.HasMaxSize ? Constraint.MaxSize : (long?)null,
true);
}
//BER encoding/decoding are implemented in base class Asn1ByteString.
#region PER
/// <summary>
/// Encodes the content of the object by PER.
/// </summary>
/// <param name="buffer">A buffer to which the encoding result will be written.</param>
/// <remarks>Length is included.</remarks>
protected override void ValuePerEncode(IAsn1PerEncodingBuffer buffer)
{
Asn1StandardProcedure.PerEncodeArray(buffer, Value.ToCharArray(),
(encodingBuffer, b) =>
{
int val;
if (Constraint == null || Constraint.PermittedCharSet == null)
{
if (b == ' ') //SPACE->0000, '0'->0001, ..., '9'->1010
{
val = 0;
}
else
{
val = 1 + b - '0';
}
}
else
{
for (val = 0; val != CharSetInArray.Length && b != CharSetInArray[val]; val++)
{
}
}
Asn1Integer ai = new Asn1Integer(val, 0, 15);
ai.PerEncode(buffer);
}
, Constraint != null && Constraint.HasMinSize ? Constraint.MinSize : (long?)null, Constraint != null && Constraint.HasMaxSize ? Constraint.MaxSize : (long?)null,
true);
}
/// <summary>
/// Decodes the object by PER.
/// </summary>
/// <param name="buffer">A buffer that contains a PER encoding result.</param>
/// <param name="aligned">Indicating whether the PER decoding is aligned.</param>
/// <remarks>Length is included.</remarks>
protected override void ValuePerDecode(IAsn1DecodingBuffer buffer, bool aligned = true)
{
if (Constraint != null && Constraint.HasMinSize && Constraint.HasMinSize &&
Constraint.MinSize == Constraint.MaxSize && Constraint.MinSize <= 2) //Ref. X.691:16.6
{
long minSize = Constraint.MinSize;
bool[] bitResult = buffer.ReadBits((int)(8 * minSize));
byte[] byteResult = new byte[(int)minSize];
//Convert bool array to byte array
int byteIndex = 0, bitIndex = 0;
foreach (bool b in bitResult)
{
if (b)
{
byteResult[byteIndex] |= (byte)(1 << (7 - bitIndex));
}
bitIndex++;
if (bitIndex == 8)
{
bitIndex = 0;
byteIndex++;
}
}
ByteArrayValue = byteResult;
}
else
{
ByteArrayValue = Asn1StandardProcedure.PerDecodeArray(buffer,
decodingBuffer => decodingBuffer.ReadByte(),
Constraint != null && Constraint.HasMinSize ? Constraint.MinSize : (long?)null, Constraint != null && Constraint.HasMaxSize ? Constraint.MaxSize : (long?)null);
}
}
//BER encoding/decoding are implemented in base class Asn1ByteString.
/// <summary>
/// Encodes the content of the object by PER.
/// </summary>
/// <param name="buffer">A buffer to which the encoding result will be written.</param>
/// <remarks>Length is included.</remarks>
protected override void ValuePerEncode(IAsn1PerEncodingBuffer buffer)
{
if (Constraint != null && Constraint.HasMinSize && Constraint.HasMinSize &&
Constraint.MinSize == Constraint.MaxSize && Constraint.MinSize <= 2) //Ref. X.691:16.6
{
buffer.WriteBits(ByteArrayValue, 0, ByteArrayValue.Length * 8);
}
else
{
Asn1StandardProcedure.PerEncodeArray(buffer, ByteArrayValue,
(encodingBuffer, b) => { encodingBuffer.WriteByte(b); }
, Constraint != null && Constraint.HasMinSize ? Constraint.MinSize : (long?)null, Constraint != null && Constraint.HasMaxSize ? Constraint.MaxSize : (long?)null);
}
}
private void DecryptAsResponse(byte[] key)
{
var encryptType = (EncryptionType)Response.enc_part.etype.Value;
int keyUsage = (int)KeyUsageNumber.AS_REP_ENCRYPTEDPART;
if (encryptType == EncryptionType.RC4_HMAC)
{
keyUsage = (int)KeyUsageNumber.TGS_REP_encrypted_part;
}
var encPartRawData = KerberosUtility.Decrypt(
encryptType,
key,
Response.enc_part.cipher.ByteArrayValue,
keyUsage);
Asn1DecodingBuffer buf = new Asn1DecodingBuffer(encPartRawData);
Asn1Tag tag = null;
Asn1StandardProcedure.TagBerDecode(buf, out tag);
//Some implementations unconditionally send an encrypted EncTGSRepPart in the field
//regardless of whether the reply is an AS-REP or a TGS-REP.([RFC4120] Section 5.4.2)
if (tag.TagValue == 25) //EncAsRepPart
{
EncPart = new EncASRepPart();
}
else if (tag.TagValue == 26) //EncTgsRepPart
{
EncPart = new EncTGSRepPart();
}
else
{
throw new Exception("Unknown tag number");
}
EncPart.BerDecode(new Asn1DecodingBuffer(encPartRawData));
KerberosUtility.OnDumpMessage("KRB5:AS-REP(enc-part)",
"Encrypted part of AS-REP",
KerberosUtility.DumpLevel.PartialMessage,
encPartRawData);
}
