# SOL - Solana

### Proof of History (PoH)

* incorporating time into the blockchain to reduce the load while processing blocks
* **Verifiable Delay Functions**
  * need sequential computation to evaluate
  * events and transactions are hashed with the SHA256 hash function
  * takes the output of a transaction and uses it as input for the next hash
  * no parallel processing allowed, able to determine exact time required to complete the steps \
    e.g. SHA256(”random string”)    output: hash1 \
           SHA256 (hash1)                    output: hash2 \
           SHA256 (hash2)                   output: hash3
  * Advantages
    * having timestamp snapshot provides a clear verifiable sequence of transactions
    * speed up validation process by minimizing node communications on timestamp
* also involve Proof of Stake (PoS) mechanism
  * only people who staked can be validator to vote on validity of PoH hash, bad actor will be penalized

### Solana Mobile - SAGA

* A flagship level Android phone targets Web 3.0 integration
* built in hardware wallet & Solana dApp Store
* simplfied dApp submission & distribution
* Solana Pay for Android