title: How to encrypt different parts of datastore with single key?
body: <p>I'd like the encrypt information stored in the datastore in Google App Engine. I would like to do this with a key hardcoded into the program and not checked into source control, such that someone who compromises the datastore couldn't read its contents.</p>
  
  <p>My issue is as follows. I need to be able to encrypt and decrypt a bunch of Strings (serialized objects turned into hex) using the same key, in an arbitrary order. This means that stream ciphers are out of the question, for key-reuse reasons. Which libraries, algorithms, or techniques will allow me to encrypt pieces of information independent of each other without weakness caused from using the same key?</p>