Issues with SHA1 hash implementation in Android

Question

I have two small snippets for calculating SHA1.

One is very fast but it seems that it isn\'t correct and the other is very slow but correct.
I think the F

Answer 1

The reason the fast one is fast and incorrect is (I think) that it is not hashing the file contents!

FileInputStream fis = new FileInputStream("C:/Users/Ich/Downloads/srware_iron.exe");
ByteArrayInputStream byteArrayInputStream = 
        new ByteArrayInputStream(fis.toString().getBytes());

The fis.toString() call does not read the contents of the file. Rather it gives you a string that (I suspect) looks something like this:

"java.io.FileInputStream@xxxxxxxx"

which you are then proceeding to calculate the SHA1 hash for. FileInputStream and its superclasses do not override Object::toString ...

---

The simple way to read the entire contents of an InputStream to a byte[] is to use an Apache Commons I/O helper method - IOUtils.toByteArray(InputStream).