Friendly & playful: 🔥 Puzzle time! First 50 correct solvers get a reward! 🔥

Riddle:

I’m made of blocks but I’m not a wall,

I keep records safe for one and all.

No single guard, yet trust remains —

What am I that secures your gains?

Reply with your answer in the comments. Only the first 50 correct answers get reward Let's go!!!!