# Proof-of-space

Proof-of-space (PoSpace), also called Proof-of-capacity (PoC), is a means of showing that one has a legitimate interest in a service (such as sending an email) by allocating a non-trivial amount of memory or disk space to solve a challenge presented by the service provider.wikipedia

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### Proof-of-work system

**proof-of-workproof of workreusable proof of work**

Proofs of space are very similar to proofs of work, except that instead of computation, storage is used.

Proof of space (PoSpace) proposals apply the same principle by proving a dedicated amount of memory or disk space instead of CPU time.

### Cryptocurrency

**cryptocurrenciescrypto-currencyaltcoin**

After the release of Bitcoin, alternatives to its PoW mining mechanism were researched and PoSpace was studied in the context of cryptocurrencies.

### Graph pebbling

**hard-to-pebble graphs**

One way of implementing PoSpace is by using hard-to-pebble graphs.

### Client Puzzle Protocol

**client puzzlecomputation-based puzzle protocols**

Proofs of space could be used as an alternative to proofs of work in the traditional client puzzle applications such as anti-spam measures and denial of service attack prevention.

### Trusted Computing

**remote attestationattestationcurtained memory**

Proof of space (PoS) have been proposed to be used for malware detection, by determining whether the L1 cache of a processor is empty (e.g., has enough space to evaluate the PoSpace routine without cache misses) or contains a routine that resisted being evicted.

### POC

Proof-of-capacity, an algorithm used to mine the Burstcoin digital cryptocurrency

### Proof of secure erasure

Proof of space is a protocol similar to proof of secure erasure in that both require the prover to dedicate a specific amount of memory to convince the verifier.