/// <summary>
/// Creates a new instance of <see cref="Signature"/> by reading it from a DER encoded byte array with loose rules.
/// Return value indicates success.
/// </summary>
/// <param name="derSig">Signature bytes encoded using DER encoding</param>
/// <param name="result">Resulting signature (null in case of failure)</param>
/// <param name="error">Error message (null if sucessful, otherwise contains information about the failure)</param>
/// <returns>True if successful, otherwise false.</returns>
public static bool TryReadLoose(byte[] derSig, out Signature result, out string error)
{
result = null;
if (derSig == null)
{
error = "Byte array can not be null.";
return(false);
}
// Min = 3006[0201(01)0201(01)]-01
if (derSig.Length < 9)
{
// This also handles the Length == 0 case
error = "Invalid DER encoding length.";
return(false);
}
FastStreamReader stream = new FastStreamReader(derSig);
if (!stream.TryReadByte(out byte seqTag) || seqTag != SequenceTag)
{
error = "Sequence tag was not found in DER encoded signature.";
return(false);
}
if (!stream.TryReadDerLength(out int seqLen))
{
error = "Invalid sequence length.";
return(false);
}
if (seqLen < 6 || !stream.CheckRemaining(seqLen + 1)) // +1 is the SigHash byte (at least 1 byte)
{
error = "Invalid total length according to sequence length.";
return(false);
}
if (!stream.TryReadByte(out byte intTag1) || intTag1 != IntegerTag)
{
error = "First integer tag was not found in DER encoded signature.";
return(false);
}
if (!stream.TryReadDerLength(out int rLen) || rLen == 0)
{
error = "Invalid R length.";
return(false);
}
if (!stream.TryReadByteArray(rLen, out byte[] rBa))
public void CheckRemainingTest()
{
var stream = new FastStreamReader(new byte[5]);
Assert.True(stream.CheckRemaining(1));
Assert.True(stream.CheckRemaining(5));
Assert.False(stream.CheckRemaining(6));
_ = stream.TryReadByteArray(2, out _);
Assert.True(stream.CheckRemaining(1));
Assert.False(stream.CheckRemaining(5));
Assert.False(stream.CheckRemaining(6));
}
public void SkipTest()
{
var stream = new FastStreamReader(new byte[10]);
Assert.Equal(0, stream.GetCurrentIndex());
stream.Skip(0);
Assert.Equal(0, stream.GetCurrentIndex());
stream.Skip(1);
Assert.Equal(1, stream.GetCurrentIndex());
stream.Skip(4);
Assert.Equal(5, stream.GetCurrentIndex());
stream.Skip(7);
Assert.Equal(12, stream.GetCurrentIndex());
Assert.False(stream.CheckRemaining(1));
}
