Bitcoin Cash is a new currency that arose as the result of a Bitcoin hard fork on August 1, 2017. This is a more scalable replicated block chain of the original Bitcoin with separate blocks that are increased to 8 megabytes.
How the "fork" works is that instead of creating a new block chain starting from zero, the fork simply creates a duplicate of the block chain with the same history.
In actuality, this means that all Bitcoin owners prior to the fork are now owners of the same amount of Bitcoin Cash, since both currencies had the same block chain up until the separation.
At its conception, the currency was worth about $700, but in the following days Bitcoin Cash stabilized in the $250-$300 range.
However, since that time, the new-born Crypto-currency has already won back its positions and has almost returned to initial indicators at about 680 USD per one Bitcoin Cash.
Dash, named for "digital cash," is an open, decentralized payment system that uses a mechanism called Darksend to anonymize transactions.
This currency has been renamed twice, from Darkcoin in 2015 and Xcoin in 2014. It offers all the features of Bitcoin, as well as instant and completely anonymous transactions through so-called Masternodes. Masternodes mix transaction data to erase all of its tracks, and then get a commission on the transaction.
The main differences between Dash and Bitcoin are: