This is the hashing algorithm that your coin will use for mining POW blocks. Each algorithm has it’s own set of advantages/disadvantages as outlined below.

**SHA256**: The original algorithm, the same one that Bitcoin uses. Use of this algorithm is generally not recommended unless you have a special reason to. ASICs (high powered, specialized mining devices) for this algorithm are widely available, which creates an unfair mining environment. Their availability also lends this algorithm to being vulnerable to numerous types of attacks involving hashpower (51% attack, etc).

**Scrypt**: The second algorithm made widely available, popularized by Litecoin. Scrypt also has ASICs available for it, however they are not as prolific as SHA256 ASICs and thus not as much of a threat to worry about. Still, this algorithm is probably not the best choice these days.

**X11**: Popularized by Darkcoin (now known as DASH), X11 uses 11 different hashing algorithms to arrive at a final hash, in a bid to stave off ASIC creation. So far it has worked, as there are no ASICs available for this algorithm. Only CPU and GPU mining is possible. This is a highly recommended algorithm.

**X13**: Similar to X11, X13 tacks on an additional 2 rounds of hashing, for a total of 13. It is very similar to X11 in that only CPU/GPU mining is possible. This is a highly recommended algorithm.

**X15**: Similar to X11, X15 tacks on an additional 4 rounds of hashing, for a total of 15. It is very similar to X11 in that only CPU/GPU mining is possible. This is a highly recommended algorithm.

For most people, X11 will end up being the best option.