Single-Signature vs. Multi-Signature

A signature sounds like one thing, so why do some setups need several before anything can move? It comes down to how many keys have to agree. Think of a bank vault that opens with a single key versus a safety-deposit box that only opens when two different keyholders show up together. Single-signature is the first case: one key is enough on its own. Multi-signature is the second: a transaction only becomes valid once a set number of independent keys have signed off.

Single-Signature

• Sole Authorization: one key alone is enough to approve and send a transaction.
• Simple Setup: fewer moving parts to configure, back up, and keep track of.
• Concentrated Control: whoever holds that one key controls everything it protects.

Multi-Signature

• Distributed Approval: a transaction only becomes valid once a set number of independent keys sign it.
• Shared Control: no single keyholder can move funds alone, since agreement from others is required.
• Added Coordination: more required signers means more setup and more coordination each time something needs approving.

The actual distinction is where authority sits: single-signature puts full authority in one key, while multi-signature spreads that authority across several so no one key is enough by itself. See Key Security for how this shows up in practice.