blog-rsa-sometimes-valid.cs

using System;
using System.Security.Cryptography;

class Program
{
    static void Main(string[] args)
    {
        var digest = new byte[] {
            0x68, 0xB4, 0xF9, 0x26, 0x34, 0x31, 0x25, 0xDD,
            0x26, 0x50, 0x13, 0x68, 0xC1, 0x99, 0x26, 0x71,
            0x19, 0xA2, 0xDE, 0x81, 
        };

        var signature = new byte[] {
            0x6A, 0xDB, 0x39, 0xE5, 0x63, 0xB3, 0x25, 0xDE,
            0x58, 0xCA, 0xC3, 0xF1, 0x36, 0x9C, 0x0B, 0x36,
            0xB7, 0xD6, 0x69, 0xF9, 0xBA, 0xA6, 0x68, 0x14,
            0x8C, 0x24, 0x52, 0xD3, 0x25, 0xA5, 0xF3, 0xAD,
            0xC9, 0x47, 0x44, 0xDE, 0x06, 0xD8, 0x0F, 0x56,
            0xCA, 0x2D, 0xFB, 0x0F, 0xE9, 0x99, 0xE2, 0x9D,
            0x8A, 0xE8, 0x7F, 0xFB, 0x9A, 0x99, 0x96, 0xF1,
            0x2C, 0x4A, 0xE4, 0xC0, 0xAE, 0x4D, 0x29, 0x47,
            0x38, 0x96, 0x51, 0x2F, 0x6D, 0x8E, 0xB8, 0x88,
            0xBD, 0x1A, 0x0A, 0x70, 0xBC, 0x23, 0x38, 0x67,
            0x62, 0x22, 0x01, 0x23, 0x71, 0xE5, 0xBB, 0x95,
            0xEA, 0x6B, 0x8D, 0x31, 0x62, 0xBF, 0xF0, 0xC4,
            0xB9, 0x46, 0xD6, 0x67, 0xFC, 0x4C, 0xE6, 0x1F,
            0xD6, 0x5D, 0xF7, 0xA9, 0xAD, 0x3A, 0xF1, 0xBF,
            0xA2, 0xF9, 0x66, 0xDE, 0xB6, 0x8E, 0xEC, 0x8F,
            0x81, 0x8D, 0x1E, 0x3A, 0x12, 0x27, 0x6A, 0xFC,
            0xAE, 0x92, 0x9F, 0xC3, 0x87, 0xC3, 0xBA, 0x8D,
            0x04, 0xB8, 0x8F, 0x0F, 0x61, 0x68, 0x9A, 0x96,
            0x2C, 0x80, 0x2C, 0x32, 0x40, 0xDE, 0x9D, 0xB9,
            0x9B, 0xE2, 0xE4, 0x45, 0x2E, 0x91, 0x47, 0x5C,
            0x47, 0xA4, 0x9D, 0x02, 0x57, 0x59, 0xF7, 0x75,
            0x5D, 0x5F, 0x32, 0x82, 0x75, 0x5D, 0xE5, 0x78,
            0xC9, 0x19, 0x61, 0x46, 0x06, 0x9D, 0xA5, 0x1D,
            0xD6, 0x32, 0x48, 0x9A, 0xDB, 0x09, 0x29, 0x81,
            0x14, 0x2E, 0xF0, 0x27, 0xE9, 0x37, 0x13, 0x74,
            0xEC, 0xA5, 0xCD, 0x67, 0x6B, 0x19, 0xF6, 0x88,
            0xF0, 0xC2, 0x8B, 0xA8, 0x7F, 0x2F, 0x76, 0x5A,
            0x3E, 0x0C, 0x47, 0x5D, 0xE8, 0x82, 0x50, 0x27,
            0x40, 0xCE, 0x27, 0x41, 0x45, 0xA0, 0xCF, 0xAA,
            0x2F, 0xD3, 0xAD, 0x3C, 0xBF, 0x73, 0xFF, 0x93,
            0xE3, 0x78, 0x49, 0xD9, 0xA9, 0x78, 0x22, 0x81,
            0x9A, 0xE5, 0xE2, 0x94, 0xE9, 0x40, 0xAB, 0xF1, 
        };

        var n = new byte[] {
            0xA2, 0x63, 0x0B, 0x39, 0x44, 0xB8, 0xBB, 0x23,
            0xA7, 0x44, 0x49, 0xBB, 0x0E, 0xFF, 0xA1, 0xF0,
            0x61, 0x0A, 0x53, 0x93, 0xB0, 0x98, 0xDB, 0xAD,
            0x2C, 0x0F, 0x4A, 0xC5, 0x6E, 0xFF, 0x86, 0x3C,
            0x53, 0x55, 0x0F, 0x15, 0xCE, 0x04, 0x3F, 0x2B,
            0xFD, 0xA9, 0x96, 0x96, 0xD9, 0xBE, 0x61, 0x79,
            0x0B, 0x5B, 0xC9, 0x4C, 0x86, 0x76, 0xE5, 0xE0,
            0x43, 0x4B, 0x22, 0x95, 0xEE, 0xC2, 0x2B, 0x43,
            0xC1, 0x9F, 0xD8, 0x68, 0xB4, 0x8E, 0x40, 0x4F,
            0xEE, 0x85, 0x38, 0xB9, 0x11, 0xC5, 0x23, 0xF2,
            0x64, 0x58, 0xF0, 0x15, 0x32, 0x6F, 0x4E, 0x57,
            0xA1, 0xAE, 0x88, 0xA4, 0x02, 0xD7, 0x2A, 0x1E,
            0xCD, 0x4B, 0xE1, 0xDD, 0x63, 0xD5, 0x17, 0x89,
            0x32, 0x5B, 0xB0, 0x5E, 0x99, 0x5A, 0xA8, 0x9D,
            0x28, 0x50, 0x0E, 0x17, 0xEE, 0x96, 0xDB, 0x61,
            0x3B, 0x45, 0x51, 0x1D, 0xCF, 0x12, 0x56, 0x0B,
            0x92, 0x47, 0xFC, 0xAB, 0xAE, 0xF6, 0x66, 0x3D,
            0x47, 0xAC, 0x70, 0x72, 0xE7, 0x92, 0xE7, 0x5F,
            0xCD, 0x10, 0xB9, 0xC4, 0x83, 0x64, 0x94, 0x19, 
            0xBD, 0x25, 0x80, 0xE1, 0xE8, 0xD2, 0x22, 0xA5,
            0xD0, 0xBA, 0x02, 0x7A, 0xA1, 0x77, 0x93, 0x5B,
            0x65, 0xC3, 0xEE, 0x17, 0x74, 0xBC, 0x41, 0x86,
            0x2A, 0xDC, 0x08, 0x4C, 0x8C, 0x92, 0x8C, 0x91,
            0x2D, 0x9E, 0x77, 0x44, 0x1F, 0x68, 0xD6, 0xA8,
            0x74, 0x77, 0xDB, 0x0E, 0x5B, 0x32, 0x8B, 0x56,
            0x8B, 0x33, 0xBD, 0xD9, 0x63, 0xC8, 0x49, 0x9D,
            0x3A, 0xC5, 0xC5, 0xEA, 0x33, 0x0B, 0xD2, 0xF1,
            0xA3, 0x1B, 0xF4, 0x8B, 0xBE, 0xD9, 0xB3, 0x57,
            0x8B, 0x3B, 0xDE, 0x04, 0xA7, 0x7A, 0x22, 0xB2,
            0x24, 0xAE, 0x2E, 0xC7, 0x70, 0xC5, 0xBE, 0x4E,
            0x83, 0x26, 0x08, 0xFB, 0x0B, 0xBD, 0xA9, 0x4F,
            0x99, 0x08, 0xE1, 0x10, 0x28, 0x72, 0xAA, 0xCD, 
        };

        var e = new byte[] {
            0x01, 0x00, 0x01
        };

        using (var rsa = new RSACng())
        {
            rsa.ImportParameters(new RSAParameters {
                Modulus = n,
                Exponent = e
            });
            var valid = rsa.VerifyHash(digest, signature, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);
            Console.WriteLine(valid);
        }
        using (var rsa = new RSACryptoServiceProvider())
        {
            rsa.ImportParameters(new RSAParameters {
                Modulus = n,
                Exponent = e
            });
            var valid = rsa.VerifyHash(digest, signature, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);
            Console.WriteLine(valid);
        }
    }
}