I want to use RSA public key encryption. What is the best way to store or retrieve private and public keys? Is XML a good idea here?

How to get the keys?

    RSAParameters privateKey = RSA.ExportParameters(true);
    RSAParameters publicKey = RSA.ExportParameters(false);

Because RSAParameters have the following members: D, DP, DQ, Exponent, InverseQ, Modulus, P, Q

Which one is the key?

How to store/retrieve RSA public/private key

I&#39;m wondering if it&#39;s possible to recover a RSA public key that I have converted to byte array previously.

    byte[] keyBytes = publicKey.getEncoded();

Thanks for the help.



How to recover a RSA public key from a byte[] array?

I recently posted about issues with encrypting large data with RSA, I am finally done with that and now I am moving on to implementing signing with a user&#39;s private key and verifying with the corresponding public key. However, whenever I compare the signed data and the original message I basically just get false returned. I am hoping some of your could see what I am doing wrong.

Here is the code:

    public static string SignData(string message, RSAParameters privateKey)
        {
            //// The array to store the signed message in bytes
            byte[] signedBytes;
            using (var rsa = new RSACryptoServiceProvider())
            {
                //// Write the message to a byte array using UTF8 as the encoding.
                var encoder = new UTF8Encoding();
                byte[] originalData = encoder.GetBytes(message);
                
                try
                {
                    //// Import the private key used for signing the message
                    rsa.ImportParameters(privateKey);

                    //// Sign the data, using SHA512 as the hashing algorithm 
                    signedBytes = rsa.SignData(originalData, CryptoConfig.MapNameToOID(&quot;SHA512&quot;));
                }
                catch (CryptographicException e)
                {
                    Console.WriteLine(e.Message);
                    return null;
                }
                finally
                {
                    //// Set the keycontainer to be cleared when rsa is garbage collected.
                    rsa.PersistKeyInCsp = false;
                }
            }
            //// Convert the a base64 string before returning
            return Convert.ToBase64String(signedBytes);
        }

So that is the first step, to sign the data, next I move on to verifying the data:

    public static bool VerifyData(string originalMessage, string signedMessage, RSAParameters publicKey)
        {
            bool success = false;
            using (var rsa = new RSACryptoServiceProvider())
            {
                byte[] bytesToVerify = Convert.FromBase64String(originalMessage);
                byte[] signedBytes = Convert.FromBase64String(signedMessage);
                try
                {
                    rsa.ImportParameters(publicKey);

                    SHA512Managed Hash = new SHA512Managed();

                    byte[] hashedData = Hash.ComputeHash(signedBytes);

                    success = rsa.VerifyData(bytesToVerify, CryptoConfig.MapNameToOID(&quot;SHA512&quot;), signedBytes);
                }
                catch (CryptographicException e)
                {
                    Console.WriteLine(e.Message);
                }
                finally
                {
                    rsa.PersistKeyInCsp = false;
                }
            }
            return success;
        }

And here is the test client:

    public static void Main(string[] args)
        {
            PublicKeyInfrastructure pki = new PublicKeyInfrastructure();
            Cryptograph crypto = new Cryptograph();
            RSAParameters privateKey = crypto.GenerateKeys(&quot;email@email.com&quot;);

            const string PlainText = &quot;This is really sent by me, really!&quot;;
 
            RSAParameters publicKey = crypto.GetPublicKey(&quot;email@email.com&quot;);

            string encryptedText = Cryptograph.Encrypt(PlainText, publicKey);

            Console.WriteLine(&quot;This is the encrypted Text:&quot; + &quot;\n &quot; + encryptedText);

            string decryptedText = Cryptograph.Decrypt(encryptedText, privateKey);

            Console.WriteLine(&quot;This is the decrypted text: &quot; + decryptedText);

            string messageToSign = encryptedText;

            string signedMessage = Cryptograph.SignData(messageToSign, privateKey);

            //// Is this message really, really, REALLY sent by me?
            bool success = Cryptograph.VerifyData(messageToSign, signedMessage, publicKey);

            Console.WriteLine(&quot;Is this message really, really, REALLY sent by me? &quot; + success);
            
        }

Am I missing a step here? According to the Cryptography API and the examples there, I shouldn&#39;t manually compute any hashes, since I supply the algorithm within the method call itself.

Any help will be greatly appreciated.



Signing and verifying signatures with RSA C#

I am encrypting data with openSSL using RSA encryption, which works fine. My understanding of RSA is, that encrypting the same data with the same public key will always give you the same result ([as stated here][1] or [here][2]). 

However, using openssl I get different results every time I repeat the encryption. 
For example:  

    ➜  ~  echo &#39;30&#39; | openssl rsautl -encrypt -inkey pub.pem -pubin  | shasum
          11b6e058273df1ebe0be5e0596e07a6c51724ca0  -

    ➜  ~  echo &#39;30&#39; | openssl rsautl -encrypt -inkey pub.pem -pubin  | shasum
          05cb82595f7429ef196189f4e781088597d90eee  -

So why is the output not unique? Is it because I got the RSA encryption wrong or because openssl does some additional magic? 


Actually I am trying to design a database which stores only RSA encrypted data. I would like to do searches on the hashsums of the encrypted information, which is impossible if the encryption procedure by itself is not unique. 
 

  [1]: http://www.learner.org/courses/mathilluminated/units/1/textbook/07.php
  [2]: https://stackoverflow.com/questions/5883451/are-rsa-signatures-unique

Why does RSA encrypted text give me different results for the same text

Is there a way to digitally sign a x509 certificate or any document using openssl?

Digital signature for a file using openssl

I am writing an app for BlackBerry that utilizes a BlackBerry smartcard reader. There is not much documentation on the subject, so I&#39;d really like if someone could give me starting examples.

Basically, there is one RSA private key on the card plus a certificate (for paired public key). I would like to be able to encrypt/decrypt data and also sign it as well. The final goal would be to establish an mutual-authenticated SSL connection using client certificate contained on the smartcard.

Here is the code I managed to come up with so far:

    SmartCardReader btReader = null;
    SmartCardReader[] readers = SmartCardReaderFactory.getInstalledReaders();
    for (int i = 0; i &lt; readers.length; i++) {
        SmartCardReader reader = readers[i];
        if (reader.getType().equalsIgnoreCase(&quot;bluetooth&quot;)) {
            btReader = reader;
            break;
        }
    }
    
    SmartCardReaderSession readerSession = reader.openSession();
    CryptoSmartCard card = (CryptoSmartCard) readerSession.getSmartCard();
    RSACryptoToken token = (RSACryptoToken) card.getCryptoToken(&quot;RSA&quot;);

This `token` looks promising - has some nice methods, but with &quot;cryptic&quot; arguments. What to do next?

Blackberry smartcard reader example

I have an instance of System.Security.Cryptography.RSACryptoServiceProvider, i need to export it&#39;s key to a PEM string - like this:

    -----BEGIN RSA PRIVATE KEY-----
    MIICXAIBAAKBgQDUNPB6Lvx+tlP5QhSikADl71AjZf9KN31qrDpXNDNHEI0OTVJ1
    OaP2l56bSKNo8trFne1NK/B4JzCuNP8x6oGCAG+7bFgkbTMzV2PCoDCRjNH957Q4
    Gxgx1VoS6PjD3OigZnx5b9Hebbp3OrTuqNZaK/oLPGr5swxHILFVeHKupQIDAQAB
    AoGAQk3MOZEGyZy0fjQ8eFKgRTfSBU1wR8Mwx6zKicbAotq0CBz2v7Pj3D+higlX
    LYp7+rUOmUc6WoB8QGJEvlb0YZVxUg1yDLMWYPE7ddsHsOkBIs7zIyS6cqhn0yZD
    VTRFjVST/EduvpUOL5hbyLSwuq+rbv0iPwGW5hkCHNEhx2ECQQDfLS5549wjiFXF
    gcio8g715eMT+20we3YmgMJDcviMGwN/mArvnBgBQsFtCTsMoOxm68SfIrBYlKYy
    BsFxn+19AkEA82q83pmcbGJRJ3ZMC/Pv+/+/XNFOvMkfT9qbuA6Lv69Z1yk7I1ie
    FTH6tOmPUu4WsIOFtDuYbfV2pvpqx7GuSQJAK3SnvRIyNjUAxoF76fGgGh9WNPjb
    DPqtSdf+e5Wycc18w+Z+EqPpRK2T7kBC4DWhcnTsBzSA8+6V4d3Q4ugKHQJATRhw
    a3xxm65kD8CbA2omh0UQQgCVFJwKy8rsaRZKUtLh/JC1h1No9kOXKTeUSmrYSt3N
    OjFp7OHCy84ihc8T6QJBANe+9xkN9hJYNK1pL1kSwXNuebzcgk3AMwHh7ThvjLgO
    jruxbM2NyMM5tl9NZCgh1vKc2v5VaonqM1NBQPDeTTw=
    -----END RSA PRIVATE KEY-----
But there is no such option according to the MSDN documentation, there is only some kind of XML export. I can&#39;t use any third party libraries like BouncyCastle.
Is there any way to generate this string? 

C# Export Private/Public RSA key from RSACryptoServiceProvider to PEM string

Can some one help me understand how an RSA key literally is stored in these formats? I would like to know the difference between the PKCS formats vs Encodings(DER, PEM). From what I understand PEM is more human readable. Is PEM/DER for keys/certs similar to UTF-8/16 for characters? What is the significance of DER/PEM? Sorry too many questions but fed up googling and getting vague answers. Thanks.

PKCS#1 and PKCS#8 format for RSA private key

After start of using NixOS as a new package management system, I get the following error when using git within Azure DevOps repositories and rsa ssh key:

    jaroslavbezdek@mac&gt; git pull
    Unable to negotiate with 40.74.28.9 port 22: no matching host key type found. Their offer: ssh-rsa
    fatal: Could not read from remote repository.
    
    Please make sure you have the correct access rights
    and the repository exists.

What can I do with that, please?

Unable to negotiate with 40.74.28.9 port 22: no matching host key type found. Their offer: ssh-rsa

I am implementing a demo for RSA Encryption and Decryption in Android. I can Perform Encryption very well, but In Decryption I get an Exception: `&gt;&gt;java.security.InvalidKeyException: unknown key type passed to RSA`.
    

        KeyPairGenerator kpg;
    	KeyPair kp;
    	PublicKey publicKey;
    	PrivateKey privateKey;
    	byte [] encryptedBytes,decryptedBytes;
        Cipher cipher,cipher1;
        String encrypted,decrypted;
    
        public String RSAEncrypt (final String plain) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException 
        {
        	kpg = KeyPairGenerator.getInstance(&quot;RSA&quot;);
            kpg.initialize(1024);
            kp = kpg.genKeyPair();
            publicKey = kp.getPublic();
            privateKey = kp.getPrivate();
            
            cipher = Cipher.getInstance(&quot;RSA&quot;);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            encryptedBytes = cipher.doFinal(plain.getBytes());
            encrypted = new String(encryptedBytes);
            System.out.println(&quot;EEncrypted?????&quot;+encrypted);
            return encrypted;
    
        }
    	
    	public String RSADecrypt (final String result) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException 
        {
    
            cipher1=Cipher.getInstance(&quot;RSA&quot;);
            cipher1.init(Cipher.DECRYPT_MODE, privateKey);
            decryptedBytes = cipher1.doFinal(result.getBytes());
            decrypted = new String(decryptedBytes);
            System.out.println(&quot;DDecrypted?????&quot;+decrypted);
            return decrypted;
    
        }
    
   

And I am calling the function from here:
    
    encrypt.setOnClickListener(new OnClickListener()
            { 
    			public void onClick(View arg0) 
    			{
    					try
    					{
    						RSAEncrypt rsaencrypt=new RSAEncrypt();
    						rsaencrypt.RSAEncrypt(name);
    						
    						result=rsaencrypt.RSAEncrypt(name);
    						Toast.makeText(getBaseContext(), result.toString(),Toast.LENGTH_SHORT).show();
    
    						System.out.println(&quot;Result:&quot;+result);
    					}
    					catch(Exception e)
    					{
    						e.printStackTrace();
    						Toast.makeText(getBaseContext(), e.toString(),Toast.LENGTH_LONG).show();
    					}
    			}
    		});
            
            decrypt.setOnClickListener(new OnClickListener()
            { 
    			public void onClick(View arg0) 
    			{
    				{
    					try
    					{
    						RSAEncrypt rsadecrypt=new RSAEncrypt();
    						
    						rsadecrypt.RSADecrypt(result);
    						
    					    ans=rsadecrypt.RSADecrypt(result);
    						System.out.println(&quot;Result is&quot;+ans);
    						Toast.makeText(getBaseContext(), ans.toString(),Toast.LENGTH_LONG).show();
    					}
    					catch(Exception e)
    					{
    						e.printStackTrace();
    						Toast.makeText(getBaseContext(), e.toString(),Toast.LENGTH_LONG).show();
    						System.out.println(&quot;Exception is&gt;&gt;&quot;+e);
    					}
    			}
    		});

RSA Encryption Decryption in Android

Am I mistaken in thinking that the security of RSA encryption, in general, is limited by the amount of known prime numbers?

To crack (or create) a private key, one has to combine the right pair of prime numbers.

Is it impossible to publish a list of all the prime numbers in the range used by RSA? Or is that list sufficiently large to make this brute force attack unlikely? Wouldn&#39;t there be &quot;commonly used&quot; prime numbers?



How many prime numbers are there (available for RSA encryption)?

I need to do the SSH key audit for GitHub, but I am not sure how do find my RSA key fingerprint. I originally followed a guide to generate an SSH key on Linux.

What is the command I need to enter to find my current RSA key fingerprint?

Calculate RSA key fingerprint

Hi I was writing a program that imports private keys from a `.pem` file and create a private key object to use it later..
the problem I have faced is that some `pem` files header begin with 

    -----BEGIN PRIVATE KEY-----

while others begin with

    -----BEGIN RSA PRIVATE KEY-----

through my search I knew that the first ones are `PKCS#8` formatted but I couldn&#39;t know what format does the other one belongs to.



Differences between &quot;BEGIN RSA PRIVATE KEY&quot; and &quot;BEGIN PRIVATE KEY&quot;

I&#39;ve just generated my RSA key pair, and I wanted to add that key to GitHub.

I tried `cd id_rsa.pub` and `id_rsa.pub`, but no luck. How can I access my SSH public key?


How do I access my SSH public key?

Where can i find some documentation on the format of an RSA public key?

An RSA public key formatted by `OpenSSH`:

&gt; ssh-rsa AAAAB3NzaC1yc2EAAAABJQAAAQB/nAmOjTmezNUDKYvEeIRf2YnwM9/uUG1d0BYsc8/tRtx+RGi7N2lUbp728MXGwdnL9od4cItzky/zVdLZE2cycOa18xBK9cOWmcKS0A8FYBxEQWJ/q9YVUgZbFKfYGaGQxsER+A0w/fX8ALuk78ktP31K69LcQgxIsl7rNzxsoOQKJ/CIxOGMMxczYTiEoLvQhapFQMs3FL96didKr/QbrfB1WT6s3838SEaXfgZvLef1YB2xmfhbT9OXFE3FXvh2UPBfN+ffE7iiayQf/2XR+8j4N4bW30DiPtOQLGUrH1y5X/rpNZNlWW2+jGIxqZtgWg7lTy3mXy5x836Sj/6L

The same public key formatted for use in Secure Shell [(RFC 4716 - The Secure Shell (SSH) Public Key File Format)][1]:

    ---- BEGIN SSH2 PUBLIC KEY ----
    AAAAB3NzaC1yc2EAAAABJQAAAQB/nAmOjTmezNUDKYvEeIRf2YnwM9/uUG1d0BYs
    c8/tRtx+RGi7N2lUbp728MXGwdnL9od4cItzky/zVdLZE2cycOa18xBK9cOWmcKS
    0A8FYBxEQWJ/q9YVUgZbFKfYGaGQxsER+A0w/fX8ALuk78ktP31K69LcQgxIsl7r
    NzxsoOQKJ/CIxOGMMxczYTiEoLvQhapFQMs3FL96didKr/QbrfB1WT6s3838SEaX
    fgZvLef1YB2xmfhbT9OXFE3FXvh2UPBfN+ffE7iiayQf/2XR+8j4N4bW30DiPtOQ
    LGUrH1y5X/rpNZNlWW2+jGIxqZtgWg7lTy3mXy5x836Sj/6L
    ---- END SSH2 PUBLIC KEY ----

The same public key formatted as an RSA public key (note the *five* **`-`**, and no space):

    -----BEGIN RSA PUBLIC KEY-----
    MIIBCgKCAQEA+xGZ/wcz9ugFpP07Nspo6U17l0YhFiFpxxU4pTk3Lifz9R3zsIsu
    ERwta7+fWIfxOo208ett/jhskiVodSEt3QBGh4XBipyWopKwZ93HHaDVZAALi/2A
    +xTBtWdEo7XGUujKDvC2/aZKukfjpOiUI8AhLAfjmlcD/UZ1QPh0mHsglRNCmpCw
    mwSXA9VNmhz+PiB+Dml4WWnKW/VHo2ujTXxq7+efMU4H2fny3Se3KYOsFPFGZ1TN
    QSYlFuShWrHPtiLmUdPoP6CV2mML1tk+l7DIIqXrQhLUKDACeM5roMx0kLhUWB8P
    +0uj1CNlNN4JRZlC7xFfqiMbFRU9Z4N6YwIDAQAB
    -----END RSA PUBLIC KEY-----

The hex dump of the base-64 encoded data:

    00 00 00 07 73 73 68 2d 72 73 61 00 00 00 01 25 00 00 01 00 7f 9c 09
    8e 8d 39 9e cc d5 03 29 8b c4 78 84 5f d9 89 f0 33 df ee 50 6d 5d d0 
    16 2c 73 cf ed 46 dc 7e 44 68 bb 37 69 54 6e 9e f6 f0 c5 c6 c1 d9 cb
    f6 87 78 70 8b 73 93 2f f3 55 d2 d9 13 67 32 70 e6 b5 f3 10 4a f5 c3 
    96 99 c2 92 d0 0f 05 60 1c 44 41 62 7f ab d6 15 52 06 5b 14 a7 d8 19 
    a1 90 c6 c1 11 f8 0d 30 fd f5 fc 00 bb a4 ef c9 2d 3f 7d 4a eb d2 dc 
    42 0c 48 b2 5e eb 37 3c 6c a0 e4 0a 27 f0 88 c4 e1 8c 33 17 33 61 38 
    84 a0 bb d0 85 aa 45 40 cb 37 14 bf 7a 76 27 4a af f4 1b ad f0 75 59 
    3e ac df cd fc 48 46 97 7e 06 6f 2d e7 f5 60 1d b1 99 f8 5b 4f d3 97 
    14 4d c5 5e f8 76 50 f0 5f 37 e7 df 13 b8 a2 6b 24 1f ff 65 d1 fb c8 
    f8 37 86 d6 df 40 e2 3e d3 90 2c 65 2b 1f 5c b9 5f fa e9 35 93 65 59 
    6d be 8c 62 31 a9 9b 60 5a 0e e5 4f 2d e6 5f 2e 71 f3 7e 92 8f fe 8b

i&#39;ve [read that there are a couple of formats][2]&lt;sup&gt;[&#128343;][3]&lt;/sup&gt;:

&gt; Key data may be encoded in three general ways:
&gt; 
&gt; -  Binary DER-encoded format. This is sometimes called ASN.1 BER-encoded
&gt; - PEM or base64 format. This is the same data as the DER-encoded file but it is encoded in base64 with additional header and footer lines
&gt; - XML format.

If it&#39;s [ASN.1][4], the hex certainly doesn&#39;t look like it.

What&#39;s the format of an RSA public key?

-----------

See also
--------

- [RSA Key Formats][2]
- [Abstract Syntax Notation One][4]
- [Convert Base64 Public Key to XML Signature][5] &lt;sup&gt;[&#128343;][6]&lt;/sup&gt;
- [Decode PEM formats][7]


  [1]: https://www.rfc-editor.org/rfc/rfc4716
  [2]: http://www.cryptosys.net/pki/rsakeyformats.html
  [3]: https://archive.fo/AnIlM
  [4]: http://en.wikipedia.org/wiki/Abstract_Syntax_Notation_One
  [5]: http://tools.ailon.org/tools/XmlKey
  [6]: https://archive.fo/mAYWx
  [7]: https://lapo.it/asn1js/

RSA Public Key format

&lt;h3&gt;How do you use an identity file with rsync?&lt;/h3&gt;
This is the syntax I *think* I should be using with rsync to use an identity file to connect:

&lt;pre&gt;
rsync -avz -e &#39;ssh -p1234  -i ~/.ssh/1234-identity&#39;  \
&quot;/local/dir/&quot; remoteUser@22.33.44.55:&quot;/remote/dir/&quot;
&lt;/pre&gt;

But it&#39;s giving me an error:

&lt;pre&gt;
Warning: Identity file ~/.ssh/1234-identity not accessible: No such file or directory.
&lt;/pre&gt;

The file is fine, permissions are set correctly, it works when doing ssh - just not with rsync - at least in my syntax. What am I doing wrong? Is it trying to look for the identity file on the remote machine? If so, how do I specify that I want to use an identity file on my *local* machine?

How do you use an identity file with rsync?

I&#39;ve generated a private key with:

    openssl genrsa [-out file] –des3

After this I&#39;ve generated a public key with:

    openssl rsa –pubout -in private.key [-out file]

I want to sign some messages with my private key, and verify some other messages with my public key, using code like this:

    public String sign(String message) throws SignatureException{
        try {
            Signature sign = Signature.getInstance(&quot;SHA1withRSA&quot;);
            sign.initSign(privateKey);
            sign.update(message.getBytes(&quot;UTF-8&quot;));
            return new String(Base64.encodeBase64(sign.sign()),&quot;UTF-8&quot;);
        } catch (Exception ex) {
            throw new SignatureException(ex);
        }
    }

    public boolean verify(String message, String signature) throws SignatureException{
        try {
            Signature sign = Signature.getInstance(&quot;SHA1withRSA&quot;);
            sign.initVerify(publicKey);
            sign.update(message.getBytes(&quot;UTF-8&quot;));
            return sign.verify(Base64.decodeBase64(signature.getBytes(&quot;UTF-8&quot;)));
        } catch (Exception ex) {
            throw new SignatureException(ex);
        }
    }

I found a solution to convert my private key to PKCS8 format and load it. It works with some code like this:

    public PrivateKey getPrivateKey(String filename) throws Exception {

        File f = new File(filename);
        FileInputStream fis = new FileInputStream(f);
        DataInputStream dis = new DataInputStream(fis);
        byte[] keyBytes = new byte[(int) f.length()];
        dis.readFully(keyBytes);
        dis.close();
        PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory kf =
                KeyFactory.getInstance(&quot;RSA&quot;);
        return kf.generatePrivate(spec);
    }

And finally my question is: **How do I load my RSA Public Key from a file?**

I think maybe I need to convert my public key file to x509 format, and use `X509EncodedKeySpec`. But how can I do this?

Load RSA public key from file

What are the differences between `.pem`, `.cer` and `.der`?

As far as I know, `.cer` contains public key. Are there any open frameworks that I can use to encrypt my data using this public key?


What are the differences between .pem, .cer and .der?

It appears they are both encryption algorithms that require public and private keys.  Why would I pick one versus the other to provide encryption in my client server application?

What is the difference between DSA and RSA?

(I am using MAC)

My id_rsa starts with

    -----BEGIN OPENSSH PRIVATE KEY-----

but I expect it to starts with 

    -----BEGIN RSA PRIVATE KEY-----

I have send my id_rsa.pub to server administrator to get the access to server, so I don&#39;t want to generate a new key. 

1. Is there any way that I can transfer my id_rsa which is a openssh private key to a RSA private key?  (command please.)

2. If I can transfer, do I also need to transfer id_rsa.pub? (command please.) It seems id_rsa.pub doesn&#39;t have a header like id_rsa, so I am not sure if I should also transfer this.



Openssh Private Key to RSA Private Key

What&#39;s the difference between id_rsa.pub and id_dsa.pub?

I&#39;m in the process of creating a CSR, and I wonder which is arguably the best length for my RSA key.

Of course, 384 is probably too weak, and 16384 is probably too slow.

**Is there a consensus on the key length one should use, depending on the certificate lifetime?**

Edit : 
Like most people, I want my key to be reasonably strong. I&#39;m not concerned that the NSA could maybe break my key in 2019. I just want to know what&#39;s the best practice when one plan to do normal business (for example an e-commerce site)


What RSA key length should I use for my SSL certificates?

I don&#39;t really understand this one:

According to [https://www.madboa.com/geek/openssl/#key-rsa](https://www.madboa.com/geek/openssl/#key-rsa), you can generate a public key from a private key.

    openssl genrsa -out mykey.pem 1024
    openssl rsa -in mykey.pem -pubout &gt; mykey.pub

My initial thinking was that they are generated in a pair together.

Does the RSA private key contain the sum? Or the public key?


Use RSA private key to generate public key?

When trying to read a RSA private key from a file using the method

    public PrivateKey getPrivateKey()
            throws NoSuchAlgorithmException,
            InvalidKeySpecException, IOException {
        
        final InputStream inputStream = getClass().getClassLoader()
                        .getResourceAsStream(&quot;privatekey&quot;);
        byte[] privKeyBytes = null;
        try {
            privKeyBytes = IOUtils.toByteArray(inputStream);
        } catch (final IOException exception) {
            LOGGER.error(&quot;&quot;, exception);
            IOUtils.closeQuietly(inputStream);
        }
        
        LOGGER.debug(&quot;privKeyBytes: {}&quot;, privKeyBytes);

        String BEGIN = &quot;-----BEGIN RSA PRIVATE KEY-----&quot;;
        String END = &quot;-----END RSA PRIVATE KEY-----&quot;;
        String str = new String(privKeyBytes);
        if (str.contains(BEGIN) &amp;&amp; str.contains(END)) {
            str = str.substring(BEGIN.length(), str.lastIndexOf(END));
        }

        KeyFactory fac = KeyFactory.getInstance(&quot;RSA&quot;);
        EncodedKeySpec privKeySpec =
                new PKCS8EncodedKeySpec(Base64.decode(str.getBytes()));
        return fac.generatePrivate(privKeySpec);
    }

I get the exception

    java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException : algid parse error, not a sequence
    	at sun.security.rsa.RSAKeyFactory.engineGeneratePrivate(RSAKeyFactory.java:200) ~[na:1.6.0_23]
    	at java.security.KeyFactory.generatePrivate(KeyFactory.java:342) ~[na:1.6.0_23]

at the fac.generatePrivate(privKeySpec) call.

What does this error mean?

Thanks

Dmitri

Algid parse error, not a sequence

I see stuff all over Google on how to see the RSA key fingerprint, but not the ECDSA fingerprint.

What command do I use to see what the ECDSA key fingerprint of my server is?

I&#39;ve seen plenty of encryption/decryption tutorials and examples on the net in C# that use the System.Security.Cryptography.RSACryptoServiceProvider, but what I&#39;m hoping to be able to do is:

 - Create an RSA public/private keypair
 - Transmit the public key (or for proof of concept, just move it in a string variable)
 - Create a new RSA crypto provider and encrypt a string with the public key
 - Transmit the encrypted string (or data) back to the original crypto provider and decrypt the string

Could anyone point me to a useful resource for this?

C# RSA encryption/decryption with transmission

I&#39;ve got an `RSA` private key in `PEM` format, is there a straight forward way to read that from .NET and instantiate an `RSACryptoServiceProvider` to decrypt data encrypted with the corresponding public key?

How to read a PEM RSA private key from .NET

RSA private keys may be assigned a &quot;passphrase&quot; which - as I understand it - is intended to provide some secondary security in case someone makes off with the private key file.

How is the passphrase layer of security implemented?

How does the RSA private key passphrase work under the hood?

Ok, I understand that the question I am asking may be pretty obvious, but unfortunately I lack the knowledge on this subject and this task seems to be quite tricky for me.

I have an id token (JWT) returned by OpenID Connect Provider. Here it is:
&gt; eyJraWQiOiIxZTlnZGs3IiwiYWxnIjoiUlMyNTYifQ.ewogImlzcyI6ICJodHRwOi8vc2VydmVyLmV4YW1wbGUuY29tIiwKICJzdWIiOiAiMjQ4Mjg5NzYxMDAxIiwKICJhdWQiOiAiczZCaGRSa3F0MyIsCiAibm9uY2UiOiAibi0wUzZfV3pBMk1qIiwKICJleHAiOiAxMzExMjgxOTcwLAogImlhdCI6IDEzMTEyODA5NzAsCiAiY19oYXNoIjogIkxEa3RLZG9RYWszUGswY25YeENsdEEiCn0.XW6uhdrkBgcGx6zVIrCiROpWURs-4goO1sKA4m9jhJIImiGg5muPUcNegx6sSv43c5DSn37sxCRrDZZm4ZPBKKgtYASMcE20SDgvYJdJS0cyuFw7Ijp_7WnIjcrl6B5cmoM6ylCvsLMwkoQAxVublMwH10oAxjzD6NEFsu9nipkszWhsPePf_rM4eMpkmCbTzume-fzZIi5VjdWGGEmzTg32h3jiex-r5WTHbj-u5HL7u_KP3rmbdYNzlzd1xWRYTUs4E8nOTgzAUwvwXkIQhOh5TPcSMBYy6X3E7-_gr9Ue6n4ND7hTFhtjYs3cjNKIA08qm5cpVYFMFMG6PkhzLQ

Its header and payload are decoded as this:

    {
     &quot;kid&quot;:&quot;1e9gdk7&quot;,
     &quot;alg&quot;:&quot;RS256&quot;
    }.
    {
     &quot;iss&quot;: &quot;http://server.example.com&quot;,
     &quot;sub&quot;: &quot;248289761001&quot;,
     &quot;aud&quot;: &quot;s6BhdRkqt3&quot;,
     &quot;nonce&quot;: &quot;n-0S6_WzA2Mj&quot;,
     &quot;exp&quot;: 1311281970,
     &quot;iat&quot;: 1311280970,
     &quot;c_hash&quot;: &quot;LDktKdoQak3Pk0cnXxCltA&quot;
    }

From the OIDC provider&#39;s discovery, I&#39;ve got the public key (JWK):

    {
     &quot;kty&quot;:&quot;RSA&quot;,
     &quot;kid&quot;:&quot;1e9gdk7&quot;,
     &quot;n&quot;:&quot;w7Zdfmece8iaB0kiTY8pCtiBtzbptJmP28nSWwtdjRu0f2GFpajvWE4VhfJAjEsOcwYzay7XGN0b-X84BfC8hmCTOj2b2eHT7NsZegFPKRUQzJ9wW8ipn_aDJWMGDuB1XyqT1E7DYqjUCEOD1b4FLpy_xPn6oV_TYOfQ9fZdbE5HGxJUzekuGcOKqOQ8M7wfYHhHHLxGpQVgL0apWuP2gDDOdTtpuld4D2LK1MZK99s9gaSjRHE8JDb1Z4IGhEcEyzkxswVdPndUWzfvWBBWXWxtSUvQGBRkuy1BHOa4sP6FKjWEeeF7gm7UMs2Nm2QUgNZw6xvEDGaLk4KASdIxRQ&quot;,
     &quot;e&quot;:&quot;AQAB&quot;
    }

So, the question is how exactly in C# can I verify this JWT using the public key for the RS256 algorithm I&#39;ve got? It would be awesome if there is a good tutorial describing this procedure explicitly. However, an example of how to do this using `System.IdentityModel.Tokens.Jwt` will also work fine.

UPDATE:
I understand, that I need to do something like the code below, but I have no idea where to get &#39;**key**&#39; for calculating SHA256 hash.

      string tokenStr = &quot;eyJraWQiOiIxZTlnZGs3IiwiYWxnIjoiUlMyNTYifQ.ewogImlzcyI6ICJodHRwOi8vc2VydmVyLmV4YW1wbGUuY29tIiwKICJzdWIiOiAiMjQ4Mjg5NzYxMDAxIiwKICJhdWQiOiAiczZCaGRSa3F0MyIsCiAibm9uY2UiOiAibi0wUzZfV3pBMk1qIiwKICJleHAiOiAxMzExMjgxOTcwLAogImlhdCI6IDEzMTEyODA5NzAsCiAiY19oYXNoIjogIkxEa3RLZG9RYWszUGswY25YeENsdEEiCn0.XW6uhdrkBgcGx6zVIrCiROpWURs-4goO1sKA4m9jhJIImiGg5muPUcNegx6sSv43c5DSn37sxCRrDZZm4ZPBKKgtYASMcE20SDgvYJdJS0cyuFw7Ijp_7WnIjcrl6B5cmoM6ylCvsLMwkoQAxVublMwH10oAxjzD6NEFsu9nipkszWhsPePf_rM4eMpkmCbTzume-fzZIi5VjdWGGEmzTg32h3jiex-r5WTHbj-u5HL7u_KP3rmbdYNzlzd1xWRYTUs4E8nOTgzAUwvwXkIQhOh5TPcSMBYy6X3E7-_gr9Ue6n4ND7hTFhtjYs3cjNKIA08qm5cpVYFMFMG6PkhzLQ&quot;;
      string[] tokenParts = tokenStr.Split(&#39;.&#39;);

      RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
      rsa.ImportParameters(
        new RSAParameters() {
          Modulus = FromBase64Url(&quot;w7Zdfmece8iaB0kiTY8pCtiBtzbptJmP28nSWwtdjRu0f2GFpajvWE4VhfJAjEsOcwYzay7XGN0b-X84BfC8hmCTOj2b2eHT7NsZegFPKRUQzJ9wW8ipn_aDJWMGDuB1XyqT1E7DYqjUCEOD1b4FLpy_xPn6oV_TYOfQ9fZdbE5HGxJUzekuGcOKqOQ8M7wfYHhHHLxGpQVgL0apWuP2gDDOdTtpuld4D2LK1MZK99s9gaSjRHE8JDb1Z4IGhEcEyzkxswVdPndUWzfvWBBWXWxtSUvQGBRkuy1BHOa4sP6FKjWEeeF7gm7UMs2Nm2QUgNZw6xvEDGaLk4KASdIxRQ&quot;),
          Exponent = FromBase64Url(&quot;AQAB&quot;)
        });

      HMACSHA256 sha = new HMACSHA256(key);
      byte[] hash = sha.ComputeHash(Encoding.UTF8.GetBytes(tokenParts[0] + &#39;.&#39; + tokenParts[1]));
      byte[] signature = rsa.Encrypt(hash, false);
      string strSignature = Base64UrlEncode(signature);
      if (String.Compare(strSignature, tokenParts[2], false) == 0)
        return true;

Verifying JWT signed with the RS256 algorithm using public key in C#

What is the difference between encrypting some data vs signing some data (using RSA)?  

Does it simply reverse the role of the public-private keys?  

For example, I want to use my private key to generate messages so only I can possibly be the sender.  I want my public key to be used to read the messages and I do not care who reads them.  I want to be able to encrypt certain information and use it as a product-key for my software.  I only care that I am the only one who can generate these.  I would like to include my public key in my software to decrypt/read the signature of the key.  I do not care who can read the data in the key, I only care that I am the only verifiable one who can generate them.

Is signing useful in this scenario?

What is the difference between encrypting and signing in asymmetric encryption?

I&#39;m trying to understand what the Java *java.security.Signature* class does. If I compute an SHA1 message digest, and then encrypt that digest using RSA, I get a different result to asking the *Signature* class to sign the same thing:

	// Generate new key
	KeyPair keyPair = KeyPairGenerator.getInstance(&quot;RSA&quot;).generateKeyPair();
	PrivateKey privateKey = keyPair.getPrivate();
	String plaintext = &quot;This is the message being signed&quot;;
	
	// Compute signature
	Signature instance = Signature.getInstance(&quot;SHA1withRSA&quot;);
	instance.initSign(privateKey);
	instance.update((plaintext).getBytes());
	byte[] signature = instance.sign();
	
	// Compute digest
	MessageDigest sha1 = MessageDigest.getInstance(&quot;SHA1&quot;);
	byte[] digest = sha1.digest((plaintext).getBytes());
	
	// Encrypt digest
	Cipher cipher = Cipher.getInstance(&quot;RSA&quot;);
	cipher.init(Cipher.ENCRYPT_MODE, privateKey);
	byte[] cipherText = cipher.doFinal(digest);
	
	// Display results
	System.out.println(&quot;Input data: &quot; + plaintext);
	System.out.println(&quot;Digest: &quot; + bytes2String(digest));
	System.out.println(&quot;Cipher text: &quot; + bytes2String(cipherText));
	System.out.println(&quot;Signature: &quot; + bytes2String(signature));

Results in (for example):

&gt;Input data: This is the message being signed  
&gt;Digest: 62b0a9ef15461c82766fb5bdaae9edbe4ac2e067  
&gt;Cipher text: 057dc0d2f7f54acc95d3cf5cba9f944619394711003bdd12...  
&gt;Signature: 7177c74bbbb871cc0af92e30d2808ebae146f25d3fd8ba1622...

I must have a fundamental misunderstanding of what *Signature* is doing - I&#39;ve traced through it, and it appears to be calling update on a *MessageDigest* object, with the algorithm set to SHA1 as I would expect, then getting the digest, then doing the encryption. What&#39;s making the results differ?

**EDIT:**

Leonidas made me check whether the signature scheme is supposed to do what I think it does. There are two types of signature defined in the [RFC][1]:

* [RSASSA-PKCS1-v1_5][2]
* [RSASSA-PSS][3]

The [first of these][2] (PKCS1) is the one I describe above. It uses a hash function to create a digest, and then encrypts the result with a private key.

The [second algorithm][3] uses a random salt value, and is more secure but non-deterministic. The signature produced from the code above does not change if the same key is used repeatedly, so I don&#39;t think it can be PSS.


  [1]: http://www.apps.ietf.org/rfc/rfc3447.html
  [2]: http://www.apps.ietf.org/rfc/rfc3447.html#sec-9.2
  [3]: http://www.apps.ietf.org/rfc/rfc3447.html#sec-9.1

**EDIT:**

Here&#39;s the `bytes2string` method I was using:

    private static String bytes2String(byte[] bytes) {
    	StringBuilder string = new StringBuilder();
    	for (byte b : bytes) {
    		String hexString = Integer.toHexString(0x00FF &amp; b);
    		string.append(hexString.length() == 1 ? &quot;0&quot; + hexString : hexString);
    	}
    	return string.toString();
    }

Using SHA1 and RSA with java.security.Signature vs. MessageDigest and Cipher

I am building a custom shopping cart where CC numbers and Exp date will be stored in a database until processing (then deleted). I need to encrypt this data (obviously).

I want to use the RSACryptoServiceProvider class.

Here is my code to create my keys.

    public static void AssignNewKey(){
        const int PROVIDER_RSA_FULL = 1;
        const string CONTAINER_NAME = &quot;KeyContainer&quot;;
        CspParameters cspParams;
        cspParams = new CspParameters(PROVIDER_RSA_FULL);
        cspParams.KeyContainerName = CONTAINER_NAME;
        cspParams.Flags = CspProviderFlags.UseMachineKeyStore;
        cspParams.ProviderName = &quot;Microsoft Strong Cryptographic Provider&quot;;
        rsa = new RSACryptoServiceProvider(cspParams);

        string publicPrivateKeyXML = rsa.ToXmlString(true);
        string publicOnlyKeyXML = rsa.ToXmlString(false);
        // do stuff with keys...
    }


Now the plan is to store the private key xml on a USB drive attached to the managers key chain.


Whenever a manager leaves the company I want to be able to generate new public and private keys (and re-encrypt all currently stored CC numbers with the new public key).

My problem is that the keys generated by this code are always the same. How would I generate a unique set of keys every time?


&lt;strong&gt;UPDATE.&lt;/strong&gt; My test code is below.:&lt;br /&gt;
&lt;em&gt;note: the &quot;privatekey&quot; parameter here is the original private key. In order for the keys to be changed I need to verify that the private key is valid.&lt;/em&gt;

In Default.aspx.cs

    public void DownloadNewPrivateKey_Click(object sender, EventArgs e)
    {
        StreamReader reader = new StreamReader(fileUpload.FileContent);
        string privateKey = reader.ReadToEnd();
        Response.Clear();
        Response.ContentType = &quot;text/xml&quot;;
        Response.End();
        Response.Write(ChangeKeysAndReturnNewPrivateKey(privateKey));
    }

In Crytpography.cs:

    public static privateKey;
    public static publicKey;
    public static RSACryptoServiceProvider rsa;

    public static string ChangeKeysAndReturnNewPrivateKey(string _privatekey)
    {
            
        string testData = &quot;TestData&quot;;
        string testSalt = &quot;salt&quot;;
        // encrypt the test data using the exisiting public key...
        string encryptedTestData = EncryptData(testData, testSalt);
        try
        {
            // try to decrypt the test data using the _privatekey provided by user...
            string decryptTestData = DecryptData(encryptedTestData, _privatekey, testSalt);
            // if the data is successfully decrypted assign new keys...
            if (decryptTestData == testData)
            {
                AssignNewKey();
                // &quot;AssignNewKey()&quot; should set &quot;privateKey&quot; to the newly created private key...
                return privateKey;
            }
            else
            {
                return string.Empty;
            }
        }
        catch (Exception ex)
        {
            return string.Empty;
        }
    }
    public static void AssignParameter(){
        const int PROVIDER_RSA_FULL = 1;
        const string CONTAINER_NAME = &quot;KeyContainer&quot;;
        CspParameters cspParams;
        cspParams = new CspParameters(PROVIDER_RSA_FULL);
        cspParams.KeyContainerName = CONTAINER_NAME;
        cspParams.Flags = CspProviderFlags.UseMachineKeyStore;
        cspParams.ProviderName = &quot;Microsoft Strong Cryptographic Provider&quot;;
        rsa = new RSACryptoServiceProvider(cspParams);
    }
    public static void AssignNewKey()
    {
        AssignParameter();
        
        using (SqlConnection myConn = new SqlConnection(Utilities.ConnectionString))
        {
            SqlCommand myCmd = myConn.CreateCommand();

            string publicPrivateKeyXML = rsa.ToXmlString(true);
            privateKey = publicPrivateKeyXML; // sets the public variable privateKey to the new private key.

            string publicOnlyKeyXML = rsa.ToXmlString(false);
            publicKey = publicOnlyKeyXML; // sets the public variable publicKey to the new public key.

            myCmd.CommandText = &quot;UPDATE Settings SET PublicKey = @PublicKey&quot;;
            myCmd.Parameters.AddWithValue(&quot;@PublicKey&quot;, publicOnlyKeyXML);
            myConn.Open();

            myComm.ExecuteScalar();
        }
    }
    public static string EncryptData(string data2Encrypt, string salt)
    {
        AssignParameter();

        using (SqlConnection myConn = new SqlConnection(Utilities.ConnectionString))
        {
            SqlCommand myCmd = myConn.CreateCommand();

            myCmd.CommandText = &quot;SELECT TOP 1 PublicKey FROM Settings&quot;;

            myConn.Open();

            using (SqlDataReader sdr = myCmd.ExecuteReader())
            {
                if (sdr.HasRows)
                {
                    DataTable dt = new DataTable();
                    dt.Load(sdr);
                    rsa.FromXmlString(dt.Rows[0][&quot;PublicKey&quot;].ToString());
                }
            }
        }

        //read plaintext, encrypt it to ciphertext
        byte[] plainbytes = System.Text.Encoding.UTF8.GetBytes(data2Encrypt + salt);
        byte[] cipherbytes = rsa.Encrypt(plainbytes, false);
        return Convert.ToBase64String(cipherbytes);
    }
    public static string DecryptData(string data2Decrypt, string privatekey, string salt)
    {
        AssignParameter();

        byte[] getpassword = Convert.FromBase64String(data2Decrypt);

        string publicPrivateKeyXML = privatekey;
        rsa.FromXmlString(publicPrivateKeyXML);
 
        //read ciphertext, decrypt it to plaintext
        byte[] plain = rsa.Decrypt(getpassword, false);
        string dataAndSalt = System.Text.Encoding.UTF8.GetString(plain);
        return dataAndSalt.Substring(0, dataAndSalt.Length - salt.Length);
    }

How to Generate Unique Public and Private Key via RSA

I&#39;m using `crypto/rsa`, and trying to find a way to *properly* save and load a key. Is there a correct way to create a `[]byte` from an `rsa.PrivateKey`. If so, is there a way to properly do so for an `rsa.PublicKey`?

Thank you all very much.

Save and load crypto/rsa PrivateKey to and from the disk

When calling the following function :

    byte[] bytes = rsa.Encrypt(System.Text.UTF8Encoding.UTF8.GetBytes(stringToEncrypt), true);

I am now getting the error: bad length. 

With a smaller string it works, any ideas what the problem could be the string I am passing is under 200 characters.

RSA Encryption, getting bad length

I need to encrypt some data using RSA in JavaScript. All of the libraries around ask for an exponent and a modulus, yet I get a single `public.key` file from my opponent. 

How do you retrieve the public `exponent` and `modulus` part from an RSA file?

RSA: Get exponent and modulus given a public key

I am staring at this for quite a while and thanks to the [MSDN documentation][1] I cannot really figure out what&#39;s going. Basically I am loading a PFX file from the disc into a `X509Certificate2` and trying to encrypt a string using the public key and decrypt using the private key. 

Why am I puzzled: the encryption/decryption works when I pass the reference to the `RSACryptoServiceProvider` itself:

    byte[] ed1 = EncryptRSA(&quot;foo1&quot;, x.PublicKey.Key as RSACryptoServiceProvider);
    string foo1 = DecryptRSA(ed1, x.PrivateKey as RSACryptoServiceProvider);

But if the export and pass around the `RSAParameter`:

    byte[] ed = EncryptRSA(&quot;foo&quot;, (x.PublicKey.Key as RSACryptoServiceProvider).ExportParameters(false));
    string foo = DecryptRSA(ed, (x.PrivateKey as RSACryptoServiceProvider).ExportParameters(true));

...it throws a &quot;Key not valid for use in specified state.&quot; exception while trying to export the private key to `RSAParameter`. Please note that the cert the PFX is generated from is marked exportable (i.e. I used the pe flag while creating the cert). Any idea what is causing the exception?
 
   

    static void Main(string[] args)
    {
        X509Certificate2 x = new X509Certificate2(@&quot;C:\temp\certs\1\test.pfx&quot;, &quot;test&quot;);
        x.FriendlyName = &quot;My test Cert&quot;;
        
        X509Store store = new X509Store(StoreName.My, StoreLocation.LocalMachine);
        store.Open(OpenFlags.ReadWrite);
        try
        {
            store.Add(x);
        }
        finally
        {
            store.Close();
        }

        byte[] ed1 = EncryptRSA(&quot;foo1&quot;, x.PublicKey.Key as RSACryptoServiceProvider);
        string foo1 = DecryptRSA(ed1, x.PrivateKey as RSACryptoServiceProvider);

        byte[] ed = EncryptRSA(&quot;foo&quot;, (x.PublicKey.Key as RSACryptoServiceProvider).ExportParameters(false));
        string foo = DecryptRSA(ed, (x.PrivateKey as RSACryptoServiceProvider).ExportParameters(true));
    }
    
    private static byte[] EncryptRSA(string data, RSAParameters rsaParameters)
    {
        UnicodeEncoding bytConvertor = new UnicodeEncoding();
        byte[] plainData = bytConvertor.GetBytes(data);
    
        RSACryptoServiceProvider publicKey = new RSACryptoServiceProvider();
        publicKey.ImportParameters(rsaParameters);
        return publicKey.Encrypt(plainData, true);
    }
    
    private static string DecryptRSA(byte[] data, RSAParameters rsaParameters)
    {
        UnicodeEncoding bytConvertor = new UnicodeEncoding();
    
        RSACryptoServiceProvider privateKey = new RSACryptoServiceProvider();
        privateKey.ImportParameters(rsaParameters);
    
        byte[] deData = privateKey.Decrypt(data, true);
        return bytConvertor.GetString(deData);
    }
    
    private static byte[] EncryptRSA(string data, RSACryptoServiceProvider publicKey)
    {
        UnicodeEncoding bytConvertor = new UnicodeEncoding();
        byte[] plainData = bytConvertor.GetBytes(data);
    
        return publicKey.Encrypt(plainData, true);
    }
    
    private static string DecryptRSA(byte[] data, RSACryptoServiceProvider privateKey)
    {
        UnicodeEncoding bytConvertor = new UnicodeEncoding();
    
        byte[] deData = privateKey.Decrypt(data, true);
        return bytConvertor.GetString(deData);
    }

Just to clarify in the code above the bold part is throwing:
`string foo = DecryptRSA(ed, (x.PrivateKey as RSACryptoServiceProvider)**.ExportParameters(true)**);`

  [1]: http://msdn.microsoft.com/query/dev10.query?appId=Dev10IDEF1&amp;l=EN-US&amp;k=k%28SYSTEM.SECURITY.CRYPTOGRAPHY.RSACRYPTOSERVICEPROVIDER.EXPORTPARAMETERS%29;k%28TargetFrameworkMoniker-%22.NETFRAMEWORK,VERSION=V4.0%22%29;k%28DevLang-CSHARP%29&amp;rd=true





CryptographicException &quot;Key not valid for use in specified state.&quot; while trying to export RSAParameters of a X509 private key

I am working on a test harness for a SAML 1.1 Assertion Consumer Service.  The test must generate a signed SAMLResponse and submit it to the ACS encoded in Base64.  The ACS must be able to verify the signed message using the X509 public cert.

I am able to build the SAMLResponse, adding the necessary assertions, etc.  But when I try to sign the object I am running into problems.  Here is a snippet of my current code:

    String certPath = &quot;mycert.pem&quot;;
    File pubCertFile = new File(certPath);
    BufferedInputStream bis = null;
    try {
        bis = new BufferedInputStream(new FileInputStream(pubCertFile));
    } catch(FileNotFoundException e) {
        throw new Exception(&quot;Could not locate certfile at &#39;&quot; + certPath + &quot;&#39;&quot;, e);
    }
    CertificateFactory certFact = null;
    Certificate cert = null;
    try {
        certFact = CertificateFactory.getInstance(&quot;X.509&quot;);
        cert = certFact.generateCertificate(bis);
    } catch(CertificateException e) {
        throw new Exception(&quot;Could not instantiate cert&quot;, e);
    }
    bis.close();
    ArrayList&lt;Certificate&gt; certs = new ArrayList&lt;Certificate&gt;();
    certs.add(cert);
    
    String keyPath = &quot;mykey.pem&quot;;
    File privKeyFile = new File(keyPath);
    try {
        bis = new BufferedInputStream(new FileInputStream(privKeyFile));
    } catch(FileNotFoundException e) {
        throw new Exception(&quot;Could not locate keyfile at &#39;&quot; + keyPath + &quot;&#39;&quot;, e);
    }
    byte[] privKeyBytes = new byte[(int)privKeyFile.length()];
    bis.read(privKeyBytes);
    bis.close();
    KeyFactory keyFactory = KeyFactory.getInstance(&quot;RSA&quot;);
    KeySpec ks = new PKCS8EncodedKeySpec(privKeyBytes);
    RSAPrivateKey privKey = (RSAPrivateKey) keyFactory.generatePrivate(ks);
    
    samlResponse.sign(Signature.getInstance(&quot;SHA1withRSA&quot;).toString(), privKey, certs);

The error occurs on the second-to-last line.  I see the following in the console:

    java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: invalid key format


Though not customary or secure, but for sake of this thread, I am providing the public cert and private key that I am using.  I of course will re-create new ones once the problem is solved.  :)

    aj@mmdev0:~/$ cat mykey.pem
    -----BEGIN RSA PRIVATE KEY-----
    MIICXgIBAAKBgQDnbcLSlDFaDMhalcmQgclTFobpkHQHJtxMVGRlbv7zknttAVbY
    1jzGjJ6HVupndzDxA9tbiMjQujmGlS/8g5IEbVsR9o6dmcmbvujtEZ2rHZ82tMYP
    VAt2IoS/W/q2Rr1cAZ/zTKEmh0ZZjzCZFueLfrYPm3am5JLcXgVtbKwybQIDAQAB
    AoGBAJ441oettYgBUUFNQv8/HGtn7Vjl38277cVptTH8DuZr8WJ3Fe8tmWONZBzX
    eW6/eIBuyJvuCo1ZpFa0zJfxQ/Ph6QlQwdN50GNfh9RzSS6lDdfy8BRhc27sypXS
    L6c5ljB6ql+pp3DdxFhJMOs3ZmBJdeyWe7uFrkngtnM1nxZBAkEA+1hbV1Q305wa
    u8YMF1SlNIAfgLJ7buD43SEXle0egz405PFG8f8yDmvROwDiRceILGVrRbInd7Cb
    dvJKr34WOQJBAOu2+reG44rNuiXeGX1MYg6TlWYyABm7PrTrhPZkedodOQB8p7zD
    AqtDSK7RnDCoThndPW6kdNAeB+kG4ug5XdUCQHRDU8UajNRSkj8nhjJIkj6twWS7
    qsMIR7Wp+An+7C1TWg5I2UNZg2MOVnNPnlseyAuZQjy0AvOnetJTk16IGWkCQQCL
    FUbOr8rnhgiGe4yywDVDwJVw3aPtiuyvOCEWeabkqkWOIf+fg7m5cFQcwxXUKBsd
    a8vp0yQSAQZN24Bb4i2ZAkEA8xGJFlFDY9HREWZnDey5STgbUeT1wYkyKcDsUrp1
    kR/3BliGqSIfje+mSKDIZqaP+gai/8bIABYAsDP/t6+cuA==
    -----END RSA PRIVATE KEY-----
    
    aj@mmdev0:~/$ cat mycert.pem
    -----BEGIN CERTIFICATE-----
    MIID7zCCA1igAwIBAgIJAKrURaAaD6ulMA0GCSqGSIb3DQEBBQUAMIGsMQswCQYD
    VQQGEwJVUzERMA8GA1UECBMISWxsaW5vaXMxEDAOBgNVBAcTB0NoaWNhZ28xHDAa
    BgNVBAoTE0hvc3R3YXkgQ29ycG9yYXRpb24xITAfBgNVBAsTGFJlc2VhcmNoIGFu
    ZCBEZXZlbG9wbWVudDEYMBYGA1UEAxMPd3d3Lmhvc3R3YXkuY29tMR0wGwYJKoZI
    hvcNAQkBFg5hakBob3N0d2F5LmNvbTAeFw0xMDA3MTQwMjMyMDhaFw0xMTA3MTQw
    MjMyMDhaMIGsMQswCQYDVQQGEwJVUzERMA8GA1UECBMISWxsaW5vaXMxEDAOBgNV
    BAcTB0NoaWNhZ28xHDAaBgNVBAoTE0hvc3R3YXkgQ29ycG9yYXRpb24xITAfBgNV
    BAsTGFJlc2VhcmNoIGFuZCBEZXZlbG9wbWVudDEYMBYGA1UEAxMPd3d3Lmhvc3R3
    YXkuY29tMR0wGwYJKoZIhvcNAQkBFg5hakBob3N0d2F5LmNvbTCBnzANBgkqhkiG
    9w0BAQEFAAOBjQAwgYkCgYEA523C0pQxWgzIWpXJkIHJUxaG6ZB0BybcTFRkZW7+
    85J7bQFW2NY8xoyeh1bqZ3cw8QPbW4jI0Lo5hpUv/IOSBG1bEfaOnZnJm77o7RGd
    qx2fNrTGD1QLdiKEv1v6tka9XAGf80yhJodGWY8wmRbni362D5t2puSS3F4FbWys
    Mm0CAwEAAaOCARUwggERMB0GA1UdDgQWBBQI/4Inzs6OH5IquItuKhIrhPb24zCB
    4QYDVR0jBIHZMIHWgBQI/4Inzs6OH5IquItuKhIrhPb246GBsqSBrzCBrDELMAkG
    A1UEBhMCVVMxETAPBgNVBAgTCElsbGlub2lzMRAwDgYDVQQHEwdDaGljYWdvMRww
    GgYDVQQKExNIb3N0d2F5IENvcnBvcmF0aW9uMSEwHwYDVQQLExhSZXNlYXJjaCBh
    bmQgRGV2ZWxvcG1lbnQxGDAWBgNVBAMTD3d3dy5ob3N0d2F5LmNvbTEdMBsGCSqG
    SIb3DQEJARYOYWpAaG9zdHdheS5jb22CCQCq1EWgGg+rpTAMBgNVHRMEBTADAQH/
    MA0GCSqGSIb3DQEBBQUAA4GBAA388zZp6UNryC/6o44hj7wTBQdzFFM5cs3B668A
    ylAnnal+J8RMIeCHoMF4S7yFQtYdOiWeScgw3c7KXrhJK1X7fU3I+eb1t3Yp1cTI
    htyzw14AoiICFalmlVgTCsn3+uh6AXP02PTkR8osdEpUOlWap4uzSKYNKc7tLOFd
    4CkM
    -----END CERTIFICATE-----




Thanks!

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