BCCILA cheat sheet

Distributed ledger = replicated, shared, cryptographically linked record maintained by multiple participants; blockchain adds block-batching and hash chaining to a DLT.

Hash function properties relied on legally: determinism, preimage resistance, second-preimage resistance, collision resistance, and avalanche effect; SHA-256 outputs 256 bits.

Block linkage: each block header contains the prior block's hash, so altering any historical transaction changes all subsequent hashes (tamper-evidence, not immutability).

Consensus families: proof of work (probabilistic finality), proof of stake (economic finality via slashing), and BFT-class protocols (deterministic finality at 2f+1 of 3f+1 validators).

Permissionless vs permissioned: identity gating, validator admission, and read access are separate design axes; a permissioned chain can still be public to read.

Public-key model: a private key signs, the public key verifies, and the address is derived from the public key; possession of the private key equals control of the asset.

Merkle trees let a verifier prove inclusion of one transaction with O(log n) hashes; light clients rely on this and on block headers.

Forks: a soft fork tightens rules and stays backward compatible; a hard fork loosens rules and splits the network unless all nodes upgrade.

Finality vocabulary: probabilistic (more confirmations, lower reorg risk) vs deterministic (protocol guarantees no reversion after a checkpoint).

Territorial nexus tests vary: establishment, habitual residence, targeting of residents, or where the effect is felt; more than one can apply at once.

Regulatory arbitrage is limited by equivalence/recognition regimes and by reverse-solicitation rules that restrict passive marketing into a jurisdiction.

Extraterritorial reach examples: US securities and sanctions rules, EU MiCA passporting limits, and AML rules tied to the location of the provider.

Conflict of laws: parties may choose governing law, but mandatory rules (consumer, employment, sanctions) of the forum can override the choice.

Enforcement cooperation runs through MLATs, supervisory colleges, and regulator memoranda of understanding; asset freezes can cross borders quickly.

Data localization and transfer restrictions can bar sending KYC data offshore, conflicting with group-wide AML monitoring.

Tax residency and permanent establishment determine where income is taxed; treaty tie-breakers resolve dual-residence conflicts for individuals.

Service-provider licensing: a single entity serving global users may need multiple local licenses; a group structure with local entities is the usual mitigation.