Hello, bitcointalkers! I have a problem with signing transaction in my wallet implementation.  I can not understand how I can generate public key that based on my private key. I have private key that I generated randomly with 256 bits. I read in A.Antonopulos book that we can receive point on elliptic curve from private key. I received X and Y coordinates, What I need to do with it for transforming in single string row (traditional public key)?

I started my impementation of blockchain and I have question about UTXO storing. Do I need to store outputs after it was used? Or maybe I need to change them status on "used", or transfer into another collection (NoSQL )or table (relation)  of database?

Hello! I am new person in blockchain technology and I want to fasten my knowledges by writing own primitive version of blockchain. I can not understand where will be my blockchain store wallets public addresses for transactions between users. Should I use helpful database like a MongoDB or MySQL for these purposes?