RAPPOR stands for randomized aggregateable privacy-preserving ordinal response and is basically a way to make randomized response suitable for non-binary data. I will only cover the client-side of RAPPOR.

Randomized Response:    • Randomized Response Explained  

Bloom Filter:    • Bloom Filters Explained  

Differential Privacy explained:    • Differential Privacy explained  
The Mathematics behind DP:    • The Mathematics Behind Differential P...  
How to add Noise to achieve DP:    • How to Add Noise to Achieve Different...