Hashing and mining — luck finds the block, rules keep ten minutes

A hash is a fingerprint

A hash function turns any data into a fixed-length value. SHA-256, used by Bitcoin and Mobick, always returns 256 bits — 64 hex digits — whether you feed it a book or a single letter.

Three properties matter:

• Same input, same output. Anyone, anywhere, gets the same result, so it can be checked.
• A tiny change, a totally different output. One letter or one space changes everything.
• No way back. The only way to find an input from an output is to try inputs one by one.

Type below and change one character at a time. Each of the 256 cells is one bit of the hash; cells that flash blue flipped since your last input.

Type anything

Apply SHA-256 twice (Bitcoin and Mobick)

Hash (64 hex digits)

0 bits flipped since last input (of 256)

Change one character and roughly half — about 128 — flip. That is why the output gives away nothing about the input.

The count of flipped bits hovers around 128 — half. That is why editing one block breaks everything after it, as the previous lesson showed.

Mining is a hash lottery

Add one rule: a block’s hash must be below a target — in hex, it must start with a certain number of zeros.

Since you cannot aim a hash, the only way is to change the block’s nonce — 0, 1, 2, 3… — and hash again and again, like scratching lottery tickets. That is mining, and because one hash proves that much work was done, it is called proof of work.

Try it. Pick how many leading zeros you want and start. It uses double SHA-256, just like Bitcoin and Mobick.

Leading zeros

1≈162≈2563≈4,0964≈65,5365≈1,048,5766≈16,777,216

Start mining

Block contents (example)

#60,962 | prev 00000000000001df…de5c32c4 | 1 tx

nonce

0

Best hash so far

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Tries

0

My browser

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Elapsed

0.0s

Pick a difficulty and press Start. Each extra zero takes about 16 times longer on average.

Four zeros usually take about a second, five a few seconds, six a while — each extra zero takes 16 times longer on average. A real Mobick block hash starts with about thirteen zeros, so mining is done with dedicated machines (ASICs), and their electricity and hardware become the wall anyone rewriting the ledger must climb.

Who keeps the ten minutes

More miners find hashes faster and blocks come quicker — yet Bitcoin and Mobick average ten minutes. The trick is the difficulty adjustment.

Every 2,016 blocks, every node measures how long they actually took. If faster than two weeks (2,016 × 10 minutes), the target drops and mining gets harder; if slower, easier. No committee decides; every node runs the same rule. Below is the Mobick mainnet’s current epoch, live.

Watch the 2-minute explainer · 1:46 If miners double, how does ten minutes come back? Narrated; it pauses after every scene.

Read the script — full text

1. Normal. Normally, a block arrives about every ten minutes. So two thousand and sixteen blocks take about two weeks. Two thousand sixteen times ten minutes is two weeks. That's the target.
2. Twice the miners. Now, what if twice as many miners join? Four machines become eight. They find hashes twice as fast, so blocks come twice as fast too. About one every five minutes. Faster than the ten-minute target.
3. Block 2,016. Every two thousand sixteen blocks, every node checks how long they took. How long was it this time? The target was two weeks. It took one. Twice too fast, so it's time to double the difficulty.
4. Retarget. So the next two thousand sixteen blocks get twice the difficulty. The target value is cut in half, which makes it harder to hit. Still eight miners, yet blocks are back to about every ten minutes. Back to ten minutes, and nobody decided it. Every node simply ran the same rule.
5. Predict. Your turn to predict. Now half the miners leave. Eight become four. At the next retarget, what happens to the difficulty? Answer: it goes down (halves). Blocks slow down to about every twenty minutes, twice too slow. Two thousand sixteen blocks now take four weeks, double the two-week target. So the difficulty is cut in half, and blocks are back to about every ten minutes.
6. The loop. In short: more miners, harder. Fewer miners, easier. No one decides. The rule pulls the pace back to ten minutes. So where is the real Mobick chain in this loop right now? Check the live gauge just below.

The narration is synthesized speech.

Mobick mainnet · current difficulty epoch

LIVE

05041,0081,5122,016

Epoch progress

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Avg block time this epoch

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Projected difficulty

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Next retarget in

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What the winner gets

The miner who finds a block pays itself new coins in the block’s first transaction — the block reward (coinbase). Mobick’s reward is now 3.125 BMB, plus the fees of the transactions in the block. Like Bitcoin it halves on a schedule, for 21 million in total.

Mobick is currently a private chain: mining is run by the operators and every block reward goes to the public-goods wallet (the 16th). That is why most blocks in the home-page strip show “1 transaction” — just the reward.

Summary

• A hash is a fingerprint: same in, same out; a small change, a different result; no way back.
• Mining changes the nonce to find a hash below the target. Hard to find, easy to check.
• Difficulty adjusts every 2,016 blocks to keep ten minutes.
• Mobick’s block reward is 3.125 BMB and, while the chain is private, goes to the public-goods wallet.