The "data management" family contains which four patterns, and what question do they collectively answer?

Encrypting On-Chain Data, Tokenisation, Off-Chain Data Storage, and State Channel — together they answer "what data goes on-chain, in what form, and what stays off?"

Storage on a blockchain is scarce (full replication), public (no privacy by default), and permanent (immutable). The four data-management patterns each take a different cut at living with that:

• Encrypting on-chain data — keep data on-chain but confidential, by encrypting before writing.
• Tokenisation — represent a transferable asset as an on-chain token.
• Off-chain data storage — keep bulky data off-chain, anchor only its hash on-chain for integrity.
• State channel — keep high-frequency or tiny updates off-chain entirely, settling only the net result on-chain.

Two of them (encrypting, tokenisation) put data on the chain in a safer form; two (off-chain storage, state channel) keep data off the chain while still leaning on it for a guarantee.

Tokenisation vs off-chain storage — easy to confuse. Both leave the real thing off the chain, but they anchor different properties. Tokenisation puts ownership on-chain: the token is a transferable stand-in for an asset (a share, a concert ticket, a kilowatt-hour), so transferring the token is transferring the asset, and the ledger is the authoritative record of who holds it. Off-chain data storage puts only integrity on-chain: the stored hash proves a document hasn't changed since it was anchored, but nothing on the chain is owned, traded, or even readable — the data itself stays wherever it lives. Test: does the on-chain entry represent something people trade, or merely fingerprint something people store? Trade → tokenisation; fingerprint → off-chain storage.