Picture this: You're at a family harambee, collecting contributions via your brand-new “Crypto Chama Coin.” Everyone is vibing. Auntie Waithera just bought 200 tokens. Uncle Kamau is showing off his new NFT profile picture (a lion wearing shades). All is well…
Until suddenly… “Transaction invalid.”
Then... your wallet shows negative balance.
Then... ALL the tokens go to some strange wallet called “BrokeBoy.eth.”
You refresh.
Still broke.
A 51% attack has landed. Na imekugonga kama matatu ya Githurai.
In a blockchain, no one is in charge. It’s like a SACCO where everyone has a vote, and decisions are made by majority rule. Now imagine one mkora (or cartel) shows up with more than half of the voting power. That’s a 51% attack.
In short: The goon controls the game.
Let’s say you and your friends are cooking ugali. Everyone stirs the pot equally. But then one guy, let’s call him "Mike the Miner," brings 51% of the mwikos. Suddenly:
He decides how thick the ugali should be
He eats first
He says others didn’t stir properly so their portion is invalid
That’s what happens on a blockchain. The attacker controls block creation and can:
Reverse transactions (double spend)
Reject valid transactions (just because)
Mine empty blocks (out of pettiness, or vibes)
Imagine you go to a kiosk, buy airtime with your crypto, and the vendor gives you the scratch card.
Then… the attacker goes back in time (like Thanos), undoes the transaction, and spends the same crypto again somewhere else. You get your scratch card, but they get the money back.
It’s like using that one hotel receipt to claim 3 reimbursements at work. It may have happened in the 90s it should happen anymore.
Not very easy — unless you’re balling like a corrupt county official.
To perform a 51% attack, you need:
A LOT of computing power (for Proof of Work blockchains like Bitcoin)
Or a LOT of stakes (money) for Proof of Stake chains like Ethereum
That’s why attackers usually target smaller blockchains like:
Bitcoin Gold
Ethereum Classic (yes, it’s still alive like that one hit wonder musician)
Feathercoin (yes, that’s a real thing)
A 51% attack is like:
A chama where one big mama buys 51% of the shares and starts deciding the venue, menu, and what time meetings start.
Or when one guy in a WhatsApp group keeps adding their exes to the group because they’re admin.
Glad you asked, young blockchain bwana:
More miners/validators = harder to take over
Decentralization = spread power, like a proper SACCO
Punishment systems – in PoS systems, bad actors lose their stake (like clowns losing their shoes)
Community watch – if an attack starts, everyone can jump ship faster than people fleeing a multi-level marketing scam.
A 51% attack is rare, expensive, and not worth it on big chains. But on small chains? Hmm... even your local juakali dev could try something shady if they have enough GPUs and petty ambition.
So next time you’re aping into a new coin called “ShereheCoin” or “NyamaDAO” — ask yourself:
“Can someone control this like a stubborn caretaker?”
If yes… run faster hawker being chased by kanjo!
Stay safe, stay decentralized, and always check if your blockchain has a “gatekeeper” ... or a “mkora in disguise.”
#CryptoNaVituko #WekaKwaSecureChain #BlockchainsNotBlockheads
