What is Cryptocurrency?
Cryptocurrency explained simply: what it is, how it works, the most popular cryptocurrencies and how to start investing in Estonia 2026.
Cryptocurrency is a digital asset whose ownership and transfers are verified by cryptography rather than by a central authority. Funds belong to whoever holds the private key — a secret number used to sign transactions. Unlike the euro or the dollar, there is no issuer who can print balances or freeze an account.
The foundation is the blockchain: transaction blocks chained together in chronological order, with an identical copy held by thousands of independent nodes. Each block contains the previous block's hash, so altering an old transaction would break the entire chain that follows — which makes the ledger immutable in practice. The data is public and verifiable by anyone, yet accounts are pseudonymous.
The first cryptocurrency was Bitcoin (BTC) (2009), which solved the double-spending problem without a bank. Today there are thousands of cryptocurrencies; the largest by market cap are Bitcoin, Ethereum, Solana and BNB.
How Does Cryptocurrency Work?
Blockchain
Transactions are gathered into blocks linked into a chain by hashes. Every node holds a copy of the full history, so corrupting a single computer — or rewriting an old record — would not fool the network.
Keys and signatures
Your public key is your address; your private key signs the transaction. A signature can be verified without revealing the key. Whoever holds the private key controls the funds — which is why protecting it matters most of all.
Coin vs token
A coin is a blockchain's native money (BTC, ETH, SOL) and pays the transaction fees. A token is created on top of an existing chain via a smart contract (e.g. ERC-20 on Ethereum) — most stablecoins and DeFi assets are tokens.
Blockchain Consensus Mechanisms
A consensus mechanism is the rule by which thousands of independent nodes agree — without a leader — on which version of a block is true. That is what makes the network trustworthy without anyone having to trust anyone else.
Proof of Work (Bitcoin): miners spend computing power to find a valid hash, and the winner adds the block and earns the reward. That reward (currently 3.125 BTC per block after the April 2024 halving) issues new coins at a decreasing pace up to a hard cap of 21 million BTC — this coded scarcity is the basis of Bitcoin's value proposition. Proof of Stake (Ethereum since 2022): validators put up their own coins as collateral; cheat and the stake is slashed. PoS uses about 99.9% less energy than PoW.
| Mechanism | Example | Energy use | Security | On EU exchanges |
|---|---|---|---|---|
| Proof of Work (PoW) | Bitcoin (BTC) | High — computation | Very high (51% attack is costly) | Bybit, Binance |
| Proof of Stake (PoS) | Ethereum (ETH), Cardano (ADA) | Low — ~99.9% less than PoW | High (stake slashed for misbehaviour) | Bybit, Bitvavo |
| Proof of History (PoH) | Solana (SOL) | Low | High; combined with PoS | Bybit, Binance |
| Delegated PoS (DPoS) | BNB Chain | Low | Medium (fewer validators) | Binance |
Most Popular Cryptocurrencies 2026
Top 10 cryptocurrencies by market cap — with their main use, risk level and where to buy them in Estonia.
| Cryptocurrency | Market cap | Main use | Risk | Where to buy |
|---|---|---|---|---|
| BTC Bitcoin | ~$1.3T | Digital gold, store of value | Medium | Bybit |
| ETH Ethereum | ~$400B | Smart contracts, DeFi, NFTs | Medium | Bybit |
| SOL Solana | ~$90B | Fast transactions, DeFi, meme coins | High | Bybit |
| BNB BNB | ~$85B | Binance ecosystem, fee discounts | High | Binance |
| XRP XRP | ~$70B | Cross-border payments and transfers | High | Bybit |
| ADA Cardano | ~$18B | Smart contracts, academic approach | High | Bitvavo |
| AVAX Avalanche | ~$12B | DeFi, fast transactions, subnets | Very high | Bybit |
| POL Polygon (POL) | ~$6B | Ethereum Layer-2 scaling solution | Very high | Binance |
| DOT Polkadot | ~$8B | Connecting blockchains (interoperability) | Very high | Bybit |
| LINK Chainlink | ~$7B | Oracle — real-world data onto the blockchain | Very high | Bybit |
* Market caps are approximate and change constantly. Check current figures on CoinMarketCap.
Stablecoins — Crypto Without Volatility
A stablecoin is a token whose issuer promises to hold a 1:1 peg to a currency (usually USD), backing the circulating supply with cash reserves or government bonds. That lets value move on a blockchain without the volatility. Under MiCA, a stablecoin offered in the eurozone must hold an e-money (EMT) authorisation: USDC is compliant, some EU exchanges have restricted trading of USDT, and euro stablecoins EURC and EURI are growing fast thanks to the regulation.
| Stablecoin | Issuer | Backing | Market cap | Use case |
|---|---|---|---|---|
| USDT (Tether) | Tether Ltd. | USD reserves + assets | ~$120B | Trading pair, fast transfers |
| USDC | Circle (regulated) | 100% USD + government bonds | ~$40B | DeFi, institutional use |
| DAI | MakerDAO (decentralized) | Crypto collateral (over-collateralized) | ~$5B | Decentralized lending |
| EURI | Banking Circle (MiCA) | EUR reserves | ~$100M | EUR-based DeFi in Europe |
DeFi — Decentralized Finance
DeFi (Decentralized Finance) replaces banking services — lending, saving, trading — with open-source smart contracts that execute automatically, with no intermediary and no account to open. Most of it runs on Ethereum and its Layer-2 networks, where the 2024 Dencun upgrade cut transaction fees several-fold. Over $45 billion is locked in DeFi protocols (TVL — Total Value Locked).
🏦 Lending
Lend out your crypto and earn interest, or use your crypto as collateral to borrow against it.
Protocols: Aave, Compound
APY: 2–8% USDC/ETH
🔄 DEX trading
Swap cryptocurrencies directly from your wallet without registering on an exchange. Trades execute through smart contracts.
Protocols: Uniswap, Curve, dYdX
24h volume: $3–5B
💰 Staking
Stake coins to help validate a PoS network and earn issuance rewards. Liquid staking (Lido and others) gives you a token in return that you can keep using.
Protocols: Lido, Rocket Pool
ETH staking APY: ~3–4%
Why Do People Buy Cryptocurrency?
📈 Betting on scarcity
Bitcoin's supply is capped in code, and each halving (most recently in 2024) cuts the rate of new coins in half. The US spot ETFs approved in January 2024 opened the door to institutional money, making Bitcoin increasingly a portfolio asset.
💸 Borderless transfers
Funds move directly key-to-key around the clock, independent of banking hours and correspondent banks. In a stablecoin you can send a fixed-value amount anywhere in the world in minutes.
🏦 Yield from staking and DeFi
Staking on a PoS network (e.g. Ethereum) yields ~3–4% per year; DeFi lending offers a return but adds smart-contract and counterparty risk.
🛡️ Self-custody
In a wallet you control, there is no intermediary who can freeze the account. But the responsibility is entirely yours — no one can recover a lost key.
How to Start with Cryptocurrency in Estonia?
Choose a platform
Best crypto platforms: Bybit, Binance, Bitvavo
Complete KYC
ID verification with ID card or passport
Make a deposit
SEPA transfer in euros (free)
Buy cryptocurrency
Bitcoin, Ethereum or another crypto
Cryptocurrency Risks
⚠️ Volatility
A price can move tens of percent in a day, and altcoins can lose over 80% from their peak at the bottom of a market cycle. Invest only what you can afford to lose.
🔒 Loss of key
The private key or seed phrase is the access itself. Lose it and the funds are gone forever; leak it and a thief has full access. There is no reversal.
🎭 Scams and rug pulls
Rug pull: the creator pumps a new coin and disappears with the liquidity. Fake support and phishing are also common. Avoid "guaranteed profit"; use MiCA-licensed platforms.
📋 Taxes and reporting
Crypto income is taxed in Estonia at 22% (2025). From 2026 platforms report transactions to the tax authority under DAC8 — declare correctly.
📜 Smart-contract bugs
A DeFi protocol is code: a bug or exploitable vulnerability can drain the contract. Over $3B was stolen in DeFi hacks in 2022–2024. Audited does not mean safe.
🇪🇺 Regulation
MiCA is in force in full (CASP licence since 30.12.2024). Rules may tighten further and some token or stablecoin may disappear from EU exchanges — use licensed platforms.
Asset Class Risk Comparison
| Asset | Volatility | Liquidity | Regulation in Estonia |
|---|---|---|---|
| Bitcoin (BTC) | High | Very high | MiCA CASP, 22% tax |
| Altcoins (SOL, ADA, etc.) | Very high | Medium | MiCA CASP, 22% tax |
| Stablecoins (USDT, USDC) | Low | Very high | MiCA EMT/ART framework |
| DeFi protocols | Very high | Variable | Unregulated — high risk |
| Stocks (for comparison) | Medium | High | MiFID II, 22% tax |
Start with Crypto Today
Register on Bybit — best crypto platform for beginners. MiCA-licensed, low fees, SEPA EUR.
Open Free AccountAffiliate link. Commission does not increase your costs.
