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RSA encryption using modulus and exponent public key

I need to encrypt my steam login password. Before sending the auth data, steam sends this: "publickey_mod":"c511d72db5ebbba01977983eec2...","publickey_exp":"010001".
The browser encrypts password with this script:
var pubKey = RSA.getPublicKey(results.publickey_mod, results.publickey_exp);
password = password.replace(/[^\x00-\x7F]/g, ''); // remove non-standard-ASCII characters
var encryptedPassword = RSA.encrypt(password, pubKey);
I can't write a working algorithm in c# which will encrypt the password using modulus and exponent.
Here is what i tried:
static async Task Main()
{
var pubKey = SetPublicKey($"{response["publickey_mod"]}", $"{response["publickey_exp"]}");
string password = "123456";
byte[] password_byte = Encoding.ASCII.GetBytes(password);
byte[] encryptedPassword;
using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
{
RSA.ImportParameters(pubKey);
encryptedPassword = RSA.Encrypt(password_byte, false);
}
string encodingPassword = Convert.ToHexString(encryptedPassword);
Console.WriteLine(encodingPassword);
}
public static RSAParameters SetPublicKey(string modulus, string exponent)
{
RSAParameters result = new RSAParameters();
result.Modulus = Convert.FromHexString(modulus);
result.Exponent = Convert.FromHexString(exponent);
return result;
}

working algorithm:
byte[] encryptedPasswordBytes;
using (var rsaEncryptor = new RSACryptoServiceProvider())
{
var passwordBytes = Encoding.ASCII.GetBytes(password);
var rsaParameters = rsaEncryptor.ExportParameters(false);
rsaParameters.Exponent = Convert.FromHexString($"{_response_getrsakey["publickey_exp"]}");
rsaParameters.Modulus = Convert.FromHexString($"{_response_getrsakey["publickey_mod"]}");
rsaEncryptor.ImportParameters(rsaParameters);
encryptedPasswordBytes = rsaEncryptor.Encrypt(passwordBytes, false);
}
string encryptedPassword = Convert.ToBase64String(encryptedPasswordBytes);

C# BouncyCastle FIPS RSA keys to RSACryptoServiceProvider

BouncyCastle has FIPS DLLs for C# that I need to use for encryption instead of normal DLLs because of compliance. How do you import public and private keys and covert them to a RSACryptoServiceProvider in order to encrypt and decrypt.
This is how I encrypt and decrypt using the regular BouncyCastle. I just need to change the functions ImportPrivateKey and ImportPublicKey
public static string Decrypt(string privateKey, string base64Encrypted)
{
string ret = null;
using (var rsa = ImportPrivateKey(privateKey))
{
var cipherBytes = Convert.FromBase64String(base64Encrypted);
RSA rsaCng = new RSACng();
rsaCng.ImportParameters(rsa.ExportParameters(true));
byte[] plainBytes = rsaCng.Decrypt(cipherBytes, RSAEncryptionPadding.OaepSHA256);
string plaintext = Encoding.UTF8.GetString(plainBytes);
ret = plaintext;
}
return ret;
}
public static string Encrypt(string publicKey, string toEncrypt)
{
string cipherText = null;
using (var rsa = ImportPublicKey(publicKey))
{
var data = Encoding.UTF8.GetBytes(toEncrypt);
RSA rsaCng = new RSACng();
rsaCng.ImportParameters(rsa.ExportParameters(false));
byte[] cipherTextBytes = rsaCng.Encrypt(data, RSAEncryptionPadding.OaepSHA256);
cipherText = Convert.ToBase64String(cipherTextBytes);
}
return cipherText;
}
public RSACryptoServiceProvider ImportPrivateKey(string pem)
{
PemReader pr = new PemReader(new StringReader(pem));
AsymmetricCipherKeyPair KeyPair = (AsymmetricCipherKeyPair)pr.ReadObject();
RSAParameters rsaParams = DotNetUtilities.ToRSAParameters((RsaPrivateCrtKeyParameters)KeyPair.Private);
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
rsa.ImportParameters(rsaParams);
return rsa;
}
public RSACryptoServiceProvider ImportPublicKey(string pem)
{
PemReader pr = new PemReader(new StringReader(pem));
AsymmetricKeyParameter publicKey = (AsymmetricKeyParameter)pr.ReadObject();
RSAParameters rsaParams = DotNetUtilities.ToRSAParameters((RsaKeyParameters)publicKey);
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
rsa.ImportParameters(rsaParams);
return rsa;
}

Here is how I got it working. If someone else has something more simple that would be awesome!. Import the keys turn them into AsymmetricRsaPublicKey then covert them to RSAParameters and then import those.
using System.IO;
using System.Security.Cryptography;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto.Asymmetric;
using Org.BouncyCastle.Crypto.Fips;
using Org.BouncyCastle.OpenSsl;
public RSACryptoServiceProvider ImportPublicKey(string key)
{
var reader = new OpenSslPemReader(new StringReader(key));
var publicKeyInfo = (SubjectPublicKeyInfo)reader.ReadObject();
var rpckp = new AsymmetricRsaPublicKey(FipsRsa.Pkcs1v15.Algorithm, publicKeyInfo);
RSAParameters parms = new RSAParameters
{
Modulus = rpckp.Modulus.ToByteArrayUnsigned(),
Exponent = rpckp.PublicExponent.ToByteArrayUnsigned()
};
RSACryptoServiceProvider rcsp = new RSACryptoServiceProvider();
rcsp.ImportParameters(parms);
return rcsp;
}
public RSACryptoServiceProvider ImportPrivateKey(string key)
{
var reader = new OpenSslPemReader(new StringReader(key));
var keyPair = (PemKeyPair)reader.ReadObject();
var rpckp = new AsymmetricRsaPrivateKey(FipsRsa.Pkcs1v15.Algorithm, keyPair.PrivateKeyInfo);
RSAParameters parms = new RSAParameters
{
Modulus = rpckp.Modulus.ToByteArrayUnsigned(),
P = rpckp.P.ToByteArrayUnsigned(),
Q = rpckp.Q.ToByteArrayUnsigned(),
DP = rpckp.DP.ToByteArrayUnsigned(),
DQ = rpckp.DQ.ToByteArrayUnsigned(),
InverseQ = rpckp.QInv.ToByteArrayUnsigned(),
D = rpckp.PrivateExponent.ToByteArrayUnsigned(),
Exponent = rpckp.PublicExponent.ToByteArrayUnsigned()
};
RSACryptoServiceProvider rcsp = new RSACryptoServiceProvider();
rcsp.ImportParameters(parms);
return rcsp;
}

C# AES-GCM and RSA Encryption using Sytem.Secuirty.Cryptography

I am developing the post data request in c# and using AES GCM encryption and RSA encryption. As compared to the C# code with Node.js / Python for encryption, we found that C# AES GCM encryption does not have tag value in the method.
e.g How do I return below data in C# after encryption.
return {
key: aesKey,
cipher_text: encrypted,
tag,
iv
}
In Python and Node.js using JsEncrypt, forge.js.... and implementations are working fine. But, now developing the same client in the C#, do not find such libraries which I can use directly.
However, I found two classes in C# AesGcm and AesManaged for AES Encryption. But I think AesManages is only for AES not GCM encryption. Therefore, I am using AesGcm class in below example, but not sure.
The code executes the following steps:
Request client certificate from DSG.
Extract the public key from the certificate.
Encrypt PII with AES key.
Encrypt AES key with RSA public key.
Send wrapped key and PII payload to DSG tokenization.
class Program
{
static void Main(string[] args)
{
string _ApiKey = "--- YOUR API KEY ----";
string _SecretKey = " ---- YOUR SECRET KEY --------";
string jsonPlainText = "<JSON TExT>";
#region Certificate
string certificate = GetCertificate();
Certificate rawSigningCert = JsonConvert.DescrializeObject<Certificate>(certificate);
var certBytes = Encoding.UTF8.GetBytes(rawSigningCert.crt);
// X509Certificate2
var x509Certificate2 = new System.Security.Cryptography.X509Certificates.X509Certificate2(certBytes);
byte[] publicKey = x509Certificate2.GetPublicKey();
#endregion
#region AES GCM Encryption
byte[] aesGcmKey = new byte[16];
RandomNumberGenerator.Fill(aesGcmKey);
byte[] nonce = new byte[12];
RandomNumberGenerator.Fill(nonce);
byte[] tag = new byte[16];
byte[] dataToEncrypt = Encoding.UTF8.GetBytes(jsonPlainText);
byte[] cipherText = new byte[dataToEncrypt.Length];
using (AesGcm aesGcm = new AesGcm(aesGcmKey))
{
aesGcm.Encrypt(nonce, dataToEncrypt, cipherText, tag);
}
string encryptedCipher = Convert.ToBase64String(cipherText);
var keyString = Convert.ToBase64String(aesGcmKey);
var iVString = Convert.ToBase64String(nonce);
var tagString = Convert.ToBase64String(tag);
string aesGcmEncryptionString = string.Format("{0}:{1}:{2}", keyString, iVString, tagString);
#endregion
#region RSA Encryption
var rsa = new RSACryptoServiceProvider();
RSAParameters RSAKeyInfo = rsa.ExportParameters(false);
RSAKeyInfo.Modulus = publicKey;
rsa.ImportParameters(RSAKeyInfo);
byte[] encryptedSymmetricKey = RSAEncrypt(Encoding.UTF8.GetBytes(aesGcmEncryptionString), RSAKeyInfo, false);
var enc_key = Convert.ToBase64String(encryptedSymmetricKey);
var requestBodyObject = new { message = encryptedCipher, enckey = enc_key };
string jsonRequestBody = JsonConvert.SerializeObject(requestBodyObject);
#endregion
#region Calculating Message Signature
Random random = new Random();
int ClientRequestId = random.Next(0, 99999999);
var time = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
var rawSignature = _ApiKey + ClientRequestId + time + jsonRequestBody;
HMACSHA256 hashObject = new HMACSHA256(Encoding.UTF8.GetBytes(_SecretKey));
var signature = hashObject.ComputeHash(Encoding.UTF8.GetBytes(rawSignature));
var computedHmac = Convert.ToBase64String(signature);
#endregion
#region Make Request
try
{
var client = new RestClient("< API URL>");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("contentType", "application/json");
request.AddHeader("clientRequestId", ClientRequestId.ToString());
request.AddHeader("apiKey", _ApiKey);
request.AddHeader("timestamp", time.Tostring);
request.AddHeader("messageSignature", computedHmac);
request.AddJsonBody(jsonRequestBody);
request.RequestFormat = DataFormat.Json;
IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
#endregion
}
static string GetCertificate()
{
string cer = string.Empty;
// Code to get certicate .crt from the service.
//"<GET CERTICATE HERE>";
return cer;
}
static public byte[] RSAEncrpt(byte[] data, RSAParameters keyInfo, bool doOAEPPadding)
{
byte[] encryptedData;
using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
{
rsa.ImportParameters(keyInfo);
encryptedData = rsa.Encrypt(data, RSAEncryptionPadding.Pkcs1);
}
return encryptedData;
}
}
class Certificate
{
public string crt { get; set; }
}
How I can trace each steps as service is responding with incorrect message signature. Any way to verify and trace the above code steps?
Help!
Thanks in advance

How can I verify signature for open PGP using BouncyCastle

How can I verify signature for open PGP using BouncyCastle?
I am using C#
I have pulic key http://itransact.com/support/toolkit/html-connection/pgp.php
I am using BouncyCastle as open pgp library
I have signature that I recieve in query string.
According to instruction (http://itransact.com/downloads/PCFullDocument-4.4.pdf p.145) algorithm is RSA.
I checked a lot of resource but no success. As I understood I need to pass public key and signature to some Verify method.
It is also not clear if I have to convert given public key in string format to some appropriate public key object. If I have to what is the type? I have tried to convert it to RsaKeyParameters but got error message about inappropriate block on public key.
At the moment I have the following code
private bool VerifyWithPublicKey(string data, byte[] sig)
{
RSACryptoServiceProvider rsa;
using (var keyreader = new StringReader(publicKey))
{
var pemReader = new PemReader(keyreader);
var y = (RsaKeyParameters)pemReader.ReadObject();
rsa = (RSACryptoServiceProvider)RSA.Create();
var rsaParameters = new RSAParameters();
rsaParameters.Modulus = y.Modulus.ToByteArray();
rsaParameters.Exponent = y.Exponent.ToByteArray();
rsa.ImportParameters(rsaParameters);
// compute sha1 hash of the data
var sha = new SHA1CryptoServiceProvider();
byte[] hash = sha.ComputeHash(Encoding.ASCII.GetBytes(data));
// This always returns false
return rsa.VerifyHash(hash, CryptoConfig.MapNameToOID("SHA1"), sig);
}

Using RSA is not your case. You need
Define public key
Convert public ket into PgPPublicKey
Get PgpSignature object
Verify signature
To verify signature you will need original data that was signed.
public class iTransactVerifier
{
private const string PublicKey = #"-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: 4.5
mQCNAjZu
-----END PGP PUBLIC KEY BLOCK-----";
public static bool Verify(string signature, string data)
{
var inputStream = ConvertStringToStream(signature);
PgpPublicKey publicKey = ReadPublicKeyFromString();
var stream = PgpUtilities.GetDecoderStream(inputStream);
PgpObjectFactory pgpFact = new PgpObjectFactory(stream);
PgpSignatureList sList = pgpFact.NextPgpObject() as PgpSignatureList;
if (sList == null)
{
throw new InvalidOperationException("PgpObjectFactory could not create signature list");
}
PgpSignature firstSig = sList[0];
firstSig.InitVerify(publicKey);
firstSig.Update(Encoding.UTF8.GetBytes(data));
var verified = firstSig.Verify();
return verified;
}
....
private static PgpPublicKey ReadPublicKeyFromString()
{
var varstream = ConvertStringToStream(PublicKey);
var stream = PgpUtilities.GetDecoderStream(varstream);
PgpObjectFactory pgpFact = new PgpObjectFactory(stream);
var keyRing = (PgpPublicKeyRing)pgpFact.NextPgpObject();
return keyRing.GetPublicKey();
}
}

What is the difference between signing by OpenSSL and Microsoft Cryptography libraries?

I wrote two methods for signing using RSA and SHA256, the first one with OpenSSL library and the second one with Microsoft Cryptography library.
OpenSSL implementation:
private string PasswordHandler(bool verify, object userdata)
{
return userdata.ToString();
}
private string Sign(string signParams)
{
var privateCertPath = HttpContext.Current.Server.MapPath(#"~\certificate.pem");
string privateKey;
using (StreamReader sr = new StreamReader(privateCertPath))
{
privateKey = sr.ReadToEnd();
}
OpenSSL.Crypto.RSA rsa = OpenSSL.Crypto.RSA.FromPrivateKey(new BIO(privateKey), PasswordHandler, _password);
//hash method
MessageDigest md = MessageDigest.SHA1;
BIO b = new BIO(signParams);
CryptoKey ck = new CryptoKey(rsa);
byte[] res1 = MessageDigestContext.Sign(md, b, ck);
return Uri.EscapeDataString(System.Convert.ToBase64String(res1));
}
Cryptography implementation:
private string Sign(string data)
{
var privateCertPath = HttpContext.Current.Server.MapPath(#"~\certificate.pfx");
X509Certificate2 privateCert = new X509Certificate2(privateCertPath, _password, X509KeyStorageFlags.Exportable);
RSACryptoServiceProvider privateKey = (RSACryptoServiceProvider)privateCert.PrivateKey;
RSACryptoServiceProvider privateKey1 = new RSACryptoServiceProvider();
privateKey1.ImportParameters(privateKey.ExportParameters(true));
// Get the bytes to be signed from the string
var bytes = System.Text.Encoding.UTF8.GetBytes(data);
//const string sha256Oid = "2.16.840.1.101.3.4.2.1";
//HashAlgorithm algorithm = new SHA256CryptoServiceProvider();
//byte[] hashBytes = algorithm.ComputeHash(bytes);
//byte[] signature = privateKey1.SignHash(hashBytes, sha256Oid);
byte[] signature = privateKey1.SignData(bytes, "SHA256");
// Base 64 encode the sig so its 8-bit clean
return Convert.ToBase64String(signature);
}
Signing with OpenSSL works, generates valid digital signature but signing with Cryptography lib generates invalid signature so my question is what I implemented wrong?
I tried to use different encoding but it did not help. Certificates are generated correctly.
It might by also useful to tell basic info about the .pem certificate:
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC