What are the correct steps to signing a token using SHA1 in PKI

Question

I am implementing a PKI solution. My encryption of a clear text token is done as follows:
public static String encrypt(String token) throws Exception {
          Cipher cipher = Cipher.getInstance("RSA/NONE/PKCS1Padding", provider);
          cipher.init(Cipher.ENCRYPT_MODE, publicKey);
          byte[] stringBytes = token.getBytes("UTF8");
          byte[] raw = cipher.doFinal(stringBytes);
          // BASE64 encode the result
          String s = encoder.encode(raw);
          // URL Encode
          String senc = URLEncoder.encode(s, "UTF-8");
          return senc;
     }Now this is what I am doing in my code to sign the message..
public static String sign(String token) throws Exception {
                Signature signer = Signature.getInstance("SHA1/RSA", provider.getName());
          signer.initSign(privateKey);
          byte[] stringBytes = token.getBytes("UTF8");
          signer.update(stringBytes);
          byte[] signature = signer.sign();
          // BASE64 encode the string result
          String s = encoder.encode(signature);
          String senc = URLEncoder.encode(s, "UTF-8");
          return senc;
     }Please look at the method sign() and inform me if I am doing the following in the sign() method..
I am being asked to hash the clear token with SHA1 and then use the private key to encrypt it with RSA.
In my method I am signing the token using the private key but it looks like I am not hasking the token first and then signing it with the private key.
Can someone please provide me with a code snippet where in I am first hashing the token using SHA1 and then signing the key with my private key..
Thanks in advance..

Answer 1

Thanks a ton. I am using BC provider but I will switch to SHA1withRSA.
I read that Signature.update() does that but had to confirm with the experts on this excellent forum.
I do a bit of PKI implementation with various vendors every once in a while at work. I love this area of specilization and would love to gain proficiency on Security and Cryptography. Are there any good resources for people like me. I usually benefit from sample scenarios and code.
Thanks in advance..