How do I use a C# generated RSA public key in Android?

Question

I want to ensure message privacy between an Android app and C# ASP.NET server, in a situation where HTTPS can\'t be assumed to be available.

I want to use RSA to encrypt

Answer 1

Try using new BigInteger(1, modulus). BigIntegers are signed and as the modulus starts with the first bit set to 1, it will always be interpreted as a negative number.