Comparison between Bitcoin and other currencies I am doing a research about comparison between Bitcoin, Litecoin and Ripple (I am thinking about change it to Dogecoin). One of the comparison criteria is privacy. I need some information about that, for example about encryption algorithms that are used in each currency, any help please?
Ripple is a centralized system with Know Your Customer integration (passports and bank accounts etc.).

Litecoin and dogecoin add zero innovation over Bitcoin, let alone in the privacy department.

Bitcoin itself however does have some exciting privacy enhancing features in store: 


Confidential Transactions, which encrypts the amounts in the transactions making them unreadable to anyone but the sender and recipient.
Signature Aggregation makes it much easier to do coinjoin where transactions of multiple people are combined into one so that it becomes harder to identify which bitcoin belonged to whom. And it actually incentives doing this by making combined transactions smaller (cheaper).