Verify SHA1withRSA signature

Question

I have to verify the signature of files, the signature is included in an XML file generated throw C# .Net.
The public key is also extracted from the XML file. Every time I want to verify a file it returns false, I'd like to know if my code is correct or not :
Certificate cer = null;
XMLCertificateExtraction extractor = XMLCertificateExtraction.getInstance( luxtrust.Configuration.getInstance(args) );
String str = "d:\\projet_LUX_TRUST\\svn\\luxtrust.trunk
full_middleware_packages.xml";
cer = extractor.extractFromID( str );
else try{
            /* input the signature bytes */*
*            String __signature = "wIeY0g1MdbFDVsEjqfK2YGsvRfVgtofcvwmzQP6l8ZCMuud0t95GmywqT5BTPVrRWkbwzp7GzJIkaD9u629XQfz4i2q+Hfmmn8+cj+zwvXWCfG9Y+l/dL9lwcFwr6pfpnFsSucrxZTKKDA11vNerMtP7P5wC5XMyhMtI48MDBm09tsaNntr1LeJkH9FRXSbGzqStv7MAnBYQLYYPT83PBs0rnu1Kz0LRUJhxEe5EfmXeUMtkeaChzdgJCkr/eueOH/Gt1pdtOU8kl96cJSE4bmQfO+1r8uXgOpenzrw3yvMTSHqlVEIg9uttZN/QNHPpylQYpEwax2sfZN7Okxe4IA==";*
*            /* create a Signature object and initialize it with the public key */
            Signature sig = Signature.getInstance("SHA1withRSA");
            sig.initVerify(cer.getPublicKey());
            FileInputStream datafis = new FileInputStream(args[0]);
            BufferedInputStream bufin = new BufferedInputStream(datafis);
            byte[] buffer = new byte[1024];
            int len;
            while (bufin.available() != 0) {
                len = bufin.read(buffer);
                sig.update(buffer, 0, len);
            bufin.close();
            boolean verifies = sig.verify(__signature.getBytes());
            System.out.println("signature verifies: " + verifies);

Answer 1

I still didn't achieve the signature verification.
I had a doubt about the signature validity so I've done the following steps.
I took my pkcs#12 file, I used openssl to retrieve the private key, I than generated a certificate and a public key.
I've signed a binary file using the generated private key , and than went to java and tried to verify the signature without sucess.
While :
$ openssl dgst -sha1 -verify x509lx.crt.pub -signature signature.sig install_sdc.exe
Verified OKI used this code to verify the signature against the openssl generated siganture:
File pubKeyFile = new File(
                    "D:\\projet_LUX_TRUST\\svn\\luxtrust.trunk\\keys\\openssl\\x509lx.crt");
          File sigFile = new File(
                    "D:\\projet_LUX_TRUST\\svn\\luxtrust.trunk\\keys\\openssl\\signature.sig");
          File fileToSign = new File(
                    "D:\\projet_LUX_TRUST\\svn\\luxtrust.trunk\\install_sdc.exe");
          java.security.cert.Certificate certLX = importCertificate(pubKeyFile);
          Signature rsa = Signature.getInstance("SHA1withRSA");
          /* Initializing signature verification */
          rsa.initVerify(certLX.getPublicKey());
          FileInputStream datafis = new FileInputStream(fileToSign);
          BufferedInputStream bufin = new BufferedInputStream(datafis);
          byte[] buffer = new byte[1024];
          int len = 0;
          while (bufin.read(buffer) != -1) {
               rsa.update(buffer, 0, len);
          bufin.close();
          boolean verifies = rsa.verify(getBytesFromFile(sigFile));
          System.out.println("2..signature = " + getBytesFromFile(sigFile));
          System.out.println("2..signature verifies: " + verifies);
          return true;
public static java.security.cert.Certificate importCertificate(File file) {
          try {
               FileInputStream is = new FileInputStream(file);
               CertificateFactory cf = CertificateFactory.getInstance("X.509");
               java.security.cert.Certificate cert = cf.generateCertificate(is);
               return cert;
          } catch (CertificateException e) {
          } catch (IOException e) {
          return null;
private static byte[] getBytesFromFile(File file) throws IOException {
        InputStream is = new FileInputStream(file);
        System.out.println("\nDEBUG: FileInputStream is " + file);
        // Get the size of the file
        long length = file.length();
        System.out.println("DEBUG: Length of " + file + " is " + length + "\n");
         * You cannot create an array using a long type. It needs to be an int
         * type. Before converting to an int type, check to ensure that file is
         * not loarger than Integer.MAX_VALUE;
        if (length > Integer.MAX_VALUE) {
            System.out.println("File is too large to process");
            return null;
        // Create the byte array to hold the data
        byte[] bytes = new byte[(int)length];
        // Read in the bytes
        int offset = 0;
        int numRead = 0;
        while ( (offset < bytes.length)
                ( (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) ) {
            offset += numRead;
        // Ensure all the bytes have been read in
        if (offset < bytes.length) {
            throw new IOException("Could not completely read file " + file.getName());
        is.close();
        return bytes;
    }What's wrong in my code or in my comprehension of RSA SHA1 usage ?