Only RSAPrivate (Crt) KeySpec and PKCS8EncodedKeySpec supported for RSA private keys
<p>I following the steps from the link : <a href="https://stackoverflow.com/questions/11787571/how-to-read-pem-file-to-get-private-and-public-key">How to read .pem file to get private and public key</a>. I executed the following three commands:</p>

<pre><code>1. $openssl genrsa -out mykey.pem 2048
2. $openssl pkcs8 -topk8 -inform PEM -outform PEM -in mykey.pem -out private_key.pem -nocrypt
3. $ openssl rsa -in mykey.pem -pubout -outform DER -out public_key.der
</code></pre>

<p>This created three files, but when I was trying to read those through Java code I started facing below error:</p>

<pre><code>PUBLIC KEY EXPO : 65537
Only RSAPrivate(Crt)KeySpec and PKCS8EncodedKeySpec supported for RSA private keys
</code></pre>

<p>My code for reference:</p>

<pre><code>public class PublicPrivateKeyDemo {
    private static File privateKeyFile = null;
    private static File publicKeyFile = null;

    public static void main(String[] args) {
        String path = "C:/Users/test898/keys";
        privateKeyFile = new File(path + "/" + "private.pem");
        publicKeyFile = new File(path + "/" + "public.der");

        try {
            loadkeys();
        } catch (IOException | GeneralSecurityException e) {
            System.out.println(e.getMessage());
        }
    }

    private static void loadkeys() throws IOException, GeneralSecurityException {
        byte[] publicKeyBytes = new byte[(int) publicKeyFile.length()];
        FileInputStream publicFis = null;
        publicFis = new FileInputStream(publicKeyFile);
        if (publicFis.read(publicKeyBytes) &gt; 0) {
            X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(publicKeyBytes);
            KeyFactory factory = KeyFactory.getInstance("RSA");
            RSAPublicKey pubKey = (RSAPublicKey) factory.generatePublic(publicKeySpec);
            BigInteger pKeyModulus = pubKey.getModulus();
            BigInteger pKeyExponent = pubKey.getPublicExponent();
            System.out.println("PUBLIC KEY EXPO : "+pKeyExponent);

        }

        byte[] privateKeyBytes = new byte[(int) privateKeyFile.length()];
        FileInputStream privateFis = null;
        privateFis = new FileInputStream(privateKeyFile);
        if (privateFis.read(privateKeyBytes) &gt; 0) {
            //PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(privateKeyBytes);
            X509EncodedKeySpec spec = new X509EncodedKeySpec(privateKeyBytes);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            RSAPrivateKey privKey = (RSAPrivateKey) keyFactory.generatePrivate(spec);
            BigInteger pKeyModulus = privKey.getModulus();
            BigInteger pKeyExponent = privKey.getPrivateExponent();
            System.out.println("PRIVATE KEY : "+pKeyExponent);
        } 
    }
}
</code></pre>

<p>Please help me whats wrong here ? I assume Private Key should give value something simillar like below":</p>

<pre><code>21150549370950609585296765828149303178265715265804890679831411170495636016527926323370428466362501818569080118374307191403222367256185274427528812911191842330928112748042350818573390540259857225467392220170770506599589136056049534085562156615813126185240565396115577449461468695709719589257257375788267753694280485882595576829517086782992300102288858453543505912425724874212273830247789870669315715724390578125469483751830964757980799543436412647956770560679365767737577100276745456138533646455249170660612983618544127693626739283128573829732806886889896396374650462743743148634276240986662548043510018342217214342529
</code></pre>