Sort:  

There is plenty of solution in the bitsharestalk forum. Most of them are a combination of block hash and shuffling of witnesses.
Creating sufficient entropy is not a problem. Making it trust-less is a non-issue aswell. Having all of them wile having a scalable protocol is what makes it difficult.

Coin Marketplace

STEEM 0.20
TRX 0.12
JST 0.028
BTC 66043.66
ETH 3593.27
USDT 1.00
SBD 2.46