How to generate CSR (certificate signing request) in PKCS#10 format

Question

Hi,
First, I am a novice in security issues.
Problem:
I know how to generate CSR using PKCS#10 format with keytool. However I need to implement this functionality in my application. Unfortunately I can't find any docs describing this issue.
Do anybody know about some API where I just pass data and it will generate CSR for me?
Many Thanks,
Miso

Answer 1

Hi again,
After a long research I am finally able to generate PKCS#10 cert. request files:
public static void generatePKCS10() throws Exception {
        // generate PKCS10 certificate request
        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
        String sigAlg = "MD5WithRSA";
        // generate private key - use java.util.SecureRandom for entropy
        keyGen.initialize(1024, new SecureRandom());
        KeyPair keypair = keyGen.generateKeyPair();
        PublicKey publicKey = keypair.getPublic();
        PrivateKey privateKey = keypair.getPrivate();
        PKCS10 pkcs10 = new PKCS10(publicKey);
        Signature signature = Signature.getInstance(sigAlg);
        signature.initSign(privateKey);
             //common, orgUnit, org, locality, state, country
        X500Name x500Name = new X500Name(
                  "CName",               // CN
                  "OUnit",               // OU
                  "Organization",          // O
                  "Bratislava",          // L
                  "Slovakia",               // S
                  "SK");               // C
        pkcs10.encodeAndSign(new X500Signer(signature, x500Name));
        // PKCS10 request generated
        pkcs10.print(System.out);
Problem 1:
However, this generates only a request with X500 subject's name ("CN, OU, O, ..."). But I also want to specify other things like "Key Usage" (example: "Digital Signature, Key Encipherment, etc.") or "Generic IA5 String" (example: "Only for test purposes."). How to do that?
Problem 2:
I'm also having trouble to find javadoc for "sun.security" package. As you can see, I'm using "sun.security.pkcs.PKCS10" class for generating CSR in PKCS10 format, but can't find any javadoc for it.
Many thanks,
Miso