The new checks were added to catch exactly this sort of mistake early.
When constructing a BigInteger from an unsigned value in an array of
bytes, you should be using e.g.:
new BigInteger(1, Mod), new BigInteger(1, Exp)
Regards,
Pete Dettman
On 25/10/2016 3:49 PM, sesteve wrote:
> Hi,
>
> I am trying to create a public RSA key from known modulus and exponent
> values.
> I execute this line:
>
>
> byte[] Mod = { 0x8C, 0x20, ... };
> byte[] Exp = { 0x01, 0x00, 0x01 };
> var pubKey = new RsaKeyParameters(false, new BigInteger(Mod), new
> BigInteger(Exp));
>
>
> This was being executed in BouncyCastel version 1.4.0.0 without troubles,
> but when I execute it in version 1.8.1.0 I get the exeption:
>
> ex
> {"Not a valid RSA modulus\r\nParameter name: modulus"}
> Data: {System.Collections.ListDictionaryInternal}
> HResult: 0x80070057
> HelpLink: null
> InnerException: null
> Message: "Not a valid RSA modulus\r\nParameter name: modulus"
> ParamName: "modulus"
> Source: "crypto"
> StackTrace: " at
> Org.BouncyCastle.Crypto.Parameters.RsaKeyParameters..ctor(Boolean isPrivate,
> BigInteger modulus, BigInteger exponent) in
> C:\\Projects\\BouncyCastle\\C#\\bccrypto-csharp-1.8.1\\Crypto\\src\\crypto\\parameters\\RsaKeyParameters.cs:line
> 25\r\n..."
> TargetSite: {Void .ctor(Boolean, Org.BouncyCastle.Math.BigInteger,
> Org.BouncyCastle.Math.BigInteger)}
>
>
> It seems to be that "new BigInteger(Mod)" is returning with sign as -1. Does
> anyone know something about this?
> I have seen in BouncyCastle source code:
>
>
> public RsaKeyParameters(
> bool isPrivate,
> BigInteger modulus,
> BigInteger exponent)
> : base(isPrivate)
> {
> if (modulus == null)
> throw new ArgumentNullException("modulus");
> if (exponent == null)
> throw new ArgumentNullException("exponent");
> if (modulus.SignValue <= 0)
> throw new ArgumentException("Not a valid RSA
> modulus", "modulus");
> if (exponent.SignValue <= 0)
> throw new ArgumentException("Not a valid RSA
> exponent", "exponent");
>
> this.modulus = modulus;
> this.exponent = exponent;
> }
>
>
> The If statements aren't in previous version. So, Is this a trouble in BC or
> a change in RSA?
>
> Thanks a lot.
>
>
>
>
>
> --
> View this message in context:
> http://bouncy-castle.1462172.n4.nabble.com/Exception-with-RsaKeyParameters-constructor-tp4658378.html
> Sent from the Bouncy Castle - Dev mailing list archive at Nabble.com.
>
