What PoW modifications are contained in CryptoNight-Lite as implemented by Aeon? How much faster is blockchain synchronization because of these modifications compared to standard CryptoNight?
What security concerns if any do these modifications raise?
There are two modifications: the scratchpad is only half the size of regular Cryptonight (1 MB rather than 2 MB) and the number of AES iterations is halved (half a million rather than a million). This makes a light hash about 4 times as fast as a regular one.
It's a bit hard to tell how this change influences blockchain sync since different machines will have different performance behavior and bottlenecks, but for a CPU bound sync, a 4x improvement is a good first approximation.
The blockchain synchronization speed/time has little to do with the POW algorithm, in AEON there is a faster blockchain synchronization because of the pruning option available when running nodes. CryptoNight-Lite, as the name suggests, uses less CPU memory than CryptoNight (1MB instead of 2MB), making it easier on low spec devices and faster to calculate hashes. No security concerns afaik but as result ASICs are also more affordable.
