PemToXml

Converting RSA PEM key (PKCS#1) to XML compatible for .Net

Requirements:

1. Tested with python version 3.6.8 Anaconda
2. Uses pycrypto

For windows you may find binaries here: http://www.voidspace.org.uk/python/modules.shtml#pycrypto

Tested scenarios:

1. PHP encrypt/decrypt using PEM keys, C# decrypt using converted PEM to XML keys
2. C# encrypt/decrypt using using XML keys, PHP decrypt using converted XML to PEM keys

Usage:

Convert a public key from PEM to XML: python PemToXml.py -ptox -pub "path/to/public.pem"

Convert a public key from XML to PEM: python PemToXml.py -xtop -pub "path/to/public.xml"

Convert a private key from PEM to XML: python PemToXml.py -ptox -priv "path/to/private.pem"

Convert a private key from XML to PEM: python PemToXml.py -xtop -priv "path/to/private.xml"

Command line flags:

("-pub", "--public") => help="Public Key"
("-priv", "--private") => help="Private Key"
("-xtop", "--xmltopem") => help="XML to PEM"
("-ptox", "--pemtoxml") => help="PEM to XML"

.Net example

using System;
using System.Text;
using System.Security.Cryptography;

private static readonly string privateKeyXml = "...your XML here...";
private static readonly string publicKeyXml = "...your XML here...";

// see https://msdn.microsoft.com/en-us/library/system.security.cryptography.rsacryptoserviceprovider.aspx
// let exception be thrown if error
public static string Encrypt(string data)
{
    if (string.IsNullOrEmpty(data))
    {
  		return null;
    }
    byte[] dataToEncrypt = Encoding.UTF8.GetBytes(data);
    byte[] encryptedData;
    using (var rsa = new RSACryptoServiceProvider())
    {
        rsa.FromXmlString(publicKeyXml);
        encryptedData = rsa.Encrypt(dataToEncrypt, false);
    }
    return Convert.ToBase64String(encryptedData);
}

// let exception be thrown if error
public static string Decrypt(string data)
{
    if (string.IsNullOrEmpty(data))
    {
        return null;
    }
    byte[] dataToDencrypt = Convert.FromBase64String(data);
    byte[] decryptedData;
    using (var rsa = new RSACryptoServiceProvider())
    {
        rsa.FromXmlString(privateKeyXml);
        decryptedData = rsa.Decrypt(dataToDencrypt, false);
    }
    return Encoding.UTF8.GetString(decryptedData);
}