🧩 RSA vs ECDSA vs EdDSA: Which Is Best?
Compare signature algorithms and learn why blockchain uses ECDSA
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0 / 5 completed🔐 Digital Signature Algorithms
Three main algorithms dominate digital signatures: ECDSA (Bitcoin, Ethereum), RSA (legacy systems), and EdDSA (next-gen blockchains). Each has unique trade-offs.
🎮 Interactive: Algorithm Comparison
Select an algorithm to explore its characteristics, use cases, and trade-offs
ECDSA
Elliptic Curve Digital Signature Algorithm
ECDSA uses elliptic curve cryptography to create compact, efficient signatures. It's the foundation of Bitcoin and Ethereum security.
- • Small key sizes (256-bit = same security as 3072-bit RSA)
- • Fast signing and verification
- • Industry standard for blockchain
- • Battle-tested since 1985
- • Complex math (harder to implement correctly)
- • Vulnerable if nonce reused
- • Slightly slower than EdDSA
⚖️ Side-by-Side Comparison
| Feature | ECDSA | RSA | EdDSA |
|---|---|---|---|
| Key Size (bits) | 256 | 2048-4096 | 256 |
| Signature Size | ~72 bytes | 256-512 bytes | 64 bytes |
| Sign Speed | Fast | Slow | Very Fast |
| Verify Speed | Fast | Fast | Very Fast |
| Blockchain Use | ✅ Bitcoin, ETH | ❌ Rare | ✅ Solana, Cardano |
| Deterministic | ⚠️ Optional (RFC 6979) | ✅ Yes | ✅ Yes |
| Quantum Resistant | ❌ No | ❌ No | ❌ No |
🚀 Why Blockchain Chose ECDSA
Bitcoin addresses are derived from 256-bit ECDSA keys. RSA would need 3072-bit keys for equivalent security - 12x larger addresses!
ECDSA signing is fast enough for smartphones. RSA signing on mobile devices can take 100ms+ per signature - too slow for real-time transactions.
Bitcoin blocks are limited to ~1MB. With RSA's 256-byte signatures, you'd fit 70% fewer transactions per block compared to ECDSA's 72 bytes.
🔮 The Future: Post-Quantum Signatures
ECDSA, RSA, and EdDSA are all vulnerable to quantum computers (Shor's algorithm). Next-generation signature schemes being developed:
✅ Quick Summary
- ✓ECDSA: Blockchain standard. Small, fast, secure. Used by Bitcoin and Ethereum.
- ✓RSA: Legacy algorithm. Large keys/signatures. Still used for TLS/SSL but not blockchain.
- ✓EdDSA: Modern upgrade. Faster than ECDSA, deterministic. Used by Solana, Cardano.
- ✓All three are vulnerable to quantum computers (5-10 year timeline for upgrades).