1/ A high-level overview of Script, Bitcoin’s scripting language:
2/ Script’s key design goal: computationally simple and compact, with native support for cryptographic operations
3/ Script is stack-based: Every instruction is executed exactly once in a linear manner (no loops).
4/ Script is Turing Incomplete: Unable to compute arbitrarily powerful functions... by design! “Miners have to run scripts, which are submitted by arbitrary participants in the network. They should not have the power to submit a script that might have an infinite loop.”
5/ An executed Bitcoin script can result in two possible outcomes:
1. Successful execution w/ no errors —> valid transaction accepted on the blockchain
2. Unsuccessful execution w/ an error —> invalid transaction not accepted on the blockchain
1. Successful execution w/ no errors —> valid transaction accepted on the blockchain
2. Unsuccessful execution w/ an error —> invalid transaction not accepted on the blockchain
6/ Script is small: 1 byte represents 1 instruction. 256 bytes. 256 instructions. 15 are disabled. 75 are reserved.
7/ Script's instructions: basic arithmetic, basic logic, throwing errors, not throwing errors, returning early, hash functions, signature verifications, and other special instructions (CHECKMULTISIG, EQUALVERIFY, DUP, etc.)
8/ Script’s quirk: a multisignature implementation bug. CHECKMULTSIG instruction pops an extra data value off the stack and is dealt with by putting an extra dummy variable onto the stack.
9/ Executing a script: Only thing needed is a stack that can push data to and pop data from. No memory or variables needed.
10/ Bitcoin nodes, by default, have a whitelist of standard scripts, generally refusing to accept scripts that are not on the list. Most common script executed is one that specifies one public key and requires a signature for that public key to spend the coins.
11/ Some other scripts include:
Proof of Burn: script that can never be redeemed. sending coins to script establishes that they've been destroyed.
P2SH: Removes need for complex response from sender. Recipient can just specify a script's hash that the sender sends money to.
Proof of Burn: script that can never be redeemed. sending coins to script establishes that they've been destroyed.
P2SH: Removes need for complex response from sender. Recipient can just specify a script's hash that the sender sends money to.
12/ Applications of Bitcoin scripts:
Escrow Transactions (implemented using a 2 of 3 multisig transaction), Green Addresses (3rd party trust trick that resolves waiting for confirmation), efficient micropayment, lock time
Escrow Transactions (implemented using a 2 of 3 multisig transaction), Green Addresses (3rd party trust trick that resolves waiting for confirmation), efficient micropayment, lock time
13/ Info was extracted from none other than “Bitcoin and Cryptocurrency Technologies” textbook. For a deeper dive, check out github.com/Causevest/arch…
