public RSAParameters ParseRSAPublicKey()
{
RSAParameters parameters = new RSAParameters();
// Current value
byte[] value = null;
// Sanity Check
int length = 0;
// Checkpoint
int position = _parser.CurrentPosition();
// Ignore Sequence - PublicKeyInfo
length = _parser.NextSequence();
if (length != _parser.RemainingBytes())
{
StringBuilder sb = new StringBuilder("Incorrect Sequence Size. ");
sb.AppendFormat("Specified: {0}, Remaining: {1}",
length.ToString(CultureInfo.InvariantCulture),
_parser.RemainingBytes().ToString(CultureInfo.InvariantCulture));
throw new BerDecodeException(sb.ToString(), position);
}
// Checkpoint
position = _parser.CurrentPosition();
// Ignore Sequence - AlgorithmIdentifier
length = _parser.NextSequence();
if (length > _parser.RemainingBytes())
{
StringBuilder sb = new StringBuilder("Incorrect AlgorithmIdentifier Size. ");
sb.AppendFormat("Specified: {0}, Remaining: {1}",
length.ToString(CultureInfo.InvariantCulture),
_parser.RemainingBytes().ToString(CultureInfo.InvariantCulture));
throw new BerDecodeException(sb.ToString(), position);
}
// Checkpoint
position = _parser.CurrentPosition();
// Grab the OID
value = _parser.NextOID();
byte[] oid = { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01 };
if (!EqualOid(value, oid))
{
throw new BerDecodeException("Expected OID 1.2.840.113549.1.1.1", position);
}
// Optional Parameters
if (_parser.IsNextNull())
{
_parser.NextNull();
// Also OK: value = parser.Next();
}
else
{
// Gracefully skip the optional data
value = _parser.Next();
}
// Checkpoint
position = _parser.CurrentPosition();
// Ignore BitString - PublicKey
length = _parser.NextBitString();
if (length > _parser.RemainingBytes())
{
StringBuilder sb = new StringBuilder("Incorrect PublicKey Size. ");
sb.AppendFormat("Specified: {0}, Remaining: {1}",
length.ToString(CultureInfo.InvariantCulture),
(_parser.RemainingBytes()).ToString(CultureInfo.InvariantCulture));
throw new BerDecodeException(sb.ToString(), position);
}
// Checkpoint
position = _parser.CurrentPosition();
// Ignore Sequence - RSAPublicKey
length = _parser.NextSequence();
if (length < _parser.RemainingBytes())
{
StringBuilder sb = new StringBuilder("Incorrect RSAPublicKey Size. ");
sb.AppendFormat("Specified: {0}, Remaining: {1}",
length.ToString(CultureInfo.InvariantCulture),
_parser.RemainingBytes().ToString(CultureInfo.InvariantCulture));
throw new BerDecodeException(sb.ToString(), position);
}
parameters.Modulus = TrimLeadingZero(_parser.NextInteger());
parameters.Exponent = TrimLeadingZero(_parser.NextInteger());
Debug.Assert(0 == _parser.RemainingBytes());
return(parameters);
}
