What is blockchain?

A blockchain is a shared, tamper-resistant ledger that records transactions across many computers instead of one central database. Beyond coins, it is used for…

A blockchain is a shared, tamper-resistant ledger that records transactions across many computers instead of one central database. Beyond coins, it is used for supply chains, digital identity, and contracts.

Why a shared ledger changes who you trust

In a normal database, one company or bank keeps the record and everyone else trusts its copy. A blockchain spreads identical copies across many computers and adds new entries in agreed blocks, so changing an old record would mean rewriting it in many places at once. That makes the history tamper-resistant and visible to participants. It does not make everything recorded true, or every coin valuable — it shifts trust from a single keeper to a shared, hard-to-alter record, which suits supply chains, identity, and contracts.

What to do, step by step

1. Picture a notebook that many people copy, where new pages are added when the group agrees they match.
2. Remember the limit: the chain protects records after entry, but cannot check that entered information was honest.
3. Look for a need for shared trust before using one; a database is simpler when one trusted keeper exists.
4. If you hold crypto, protect your keys carefully, because the ledger cannot restore access the way a bank can.
5. Start with small, low-risk experiments and guides before putting significant money into blockchain products.