sdk/src/com/socialize/networks/facebook/FacebookUtils.java
public static String[] getHashKeys(Activity context) throws NoSuchAlgorithmException {
        PackageInfo packageInfo = null;
        String[] keys = null;
        try {
            packageInfo = context.getPackageManager().getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES);
            
            if(packageInfo != null && packageInfo.signatures != null && packageInfo.signatures.length > 0) {
            	
            	keys = new String[packageInfo.signatures.length];
            	for (int i = 0; i < packageInfo.signatures.length; i++) {
            		Signature signature = packageInfo.signatures[i];
            		MessageDigest md = MessageDigest.getInstance("SHA1");
            		md.update(signature.toByteArray());
            		String hash = new String(Base64.encode(md.digest(), 0));
            		keys[i] = hash;
				}
            }
        } 
        catch (PackageManager.NameNotFoundException e) {
        	e.printStackTrace();
        }
        
        return keys;
	}
public static String[] getHashKeys(Activity context) throws NoSuchAlgorithmException {
        PackageInfo packageInfo = null;
        String[] keys = null;
        try {
            packageInfo = context.getPackageManager().getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES);
            
            if(packageInfo != null && packageInfo.signatures != null && packageInfo.signatures.length > 0) {
            	
            	keys = new String[packageInfo.signatures.length];
            	for (int i = 0; i < packageInfo.signatures.length; i++) {
            		Signature signature = packageInfo.signatures[i];
            		MessageDigest md = MessageDigest.getInstance("SHA1");
            		md.update(signature.toByteArray());
            		String hash = new String(Base64.encode(md.digest(), 0));
            		keys[i] = hash;
				}
            }
        } 
        catch (PackageManager.NameNotFoundException e) {
        	e.printStackTrace();
        }
        
        return keys;
	}
Returns the hash key used to authenticate this application with Facebook.  Useful for debugging.
@param context
@return
@throws NoSuchAlgorithmException