internal static byte[] GetAsn1IntegerBytes(SafeSharedAsn1IntegerHandle asn1Integer)
{
CheckValidOpenSslHandle(asn1Integer);
// OpenSSL stores negative numbers in their two's complement (positive) form, but
// sets an internal negative bit.
//
// If the number was positive, but could sign-test as negative, DER puts in a leading
// 0x00 byte, which reading OpenSSL's data directly won't have.
//
// So to ensure we're getting a set of bytes compatible with BigInteger (though with the
// wrong endianness here), DER encode it, then use the DER reader to skip past the tag
// and length.
byte[] derEncoded = OpenSslEncode(
handle => GetAsn1IntegerDerSize(handle),
(handle, buf) => EncodeAsn1Integer(handle, buf),
asn1Integer);
DerSequenceReader reader = DerSequenceReader.CreateForPayload(derEncoded);
return reader.ReadIntegerBytes();
}
private static extern int EncodeAsn1Integer(SafeSharedAsn1IntegerHandle i, byte[] buf);
private static extern int GetAsn1IntegerDerSize(SafeSharedAsn1IntegerHandle i);
