ssh-rsa.snipet.java

        /**
	 * Converts the given RSAPublicKey obejct to RSA-SSH format byte array. This
	 * byte[] returned DOES NOT include the prefixed <i>ssh-rsa</i> nor any appended
	 * text (i.e. the username or email address) for a comment.
	 * 
	 * @param pubkey				java.security.interfaces.RSAPublicKey to convert.
	 * @return							byte[]
	 * @throws IOException
	 */
	public static final byte[] publicKeyToRsaSsh(RSAPublicKey pubkey) 
			throws IOException {
		
		ByteArrayOutputStream buf = new ByteArrayOutputStream();
                write(new String("ssh-rsa").getBytes("UTF-8"), buf);
	        write(pubkey.getPublicExponent().toByteArray(), buf);
	        write(pubkey.getModulus().toByteArray(), buf);
	  
	        return buf.toByteArray();
	}
	
	private static final void write(byte[] b, OutputStream o) 
			throws IOException {
		
		for(int i = 24; i >= 0; i -= 8)
			o.write((b.length >>> i) & 0xFF);
		
		o.write(b);
	}