BIP-337
Compressed Transactions.
Would define a compact encoding that can shrink a Bitcoin payment to less than half its normal size.
Many parts of a typical payment hold padding or common values that can be written more briefly. This encoding packs them tightly, and can optionally point to a coin by its block and position instead of its long ID. One aim is to make payments easier to pass along in other ways, such as hidden inside images.
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