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Public Address Mappings, FIO Requests and OBT records. Even though these records are stored on-chain today, there is already an initiative on the Roadmap to consider moving it off-chain for performance reasons and another one to consider expanding the size of the associated content.
Request for Signature. Initial feedback received from wallets indicates a preference to store such requests off-chain.
Public Address Request and Friend List functionality. During the design of FIP-5, the requirement to store data on-chain created significant complexities. If the data can recorded anonymously off-chain, the FIO Privacy solution may be much simpler.
Push notifications. Off-chain messaging solution would likely make it simpler to develop a push notification mechanism for wallets.
Secure messaging. Ability to exchange messages between FIO Addresses has long been considered for development. Recently a community member has submitted a FIP-24: Secure Message Standard, which contemplates a solution similar to Layer 2 described here.
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Performance - since transactions do not need to be recorded on-chain, they can be recorded and read faster and are not subject to throughput or size constrains, typical for on-chain transactions. Potentially overlaps with https://fioprotocol.atlassian.net/browse/WP-119
Cost - off-chain transactions can be significantly cheaper or free.
Privacy - off-chain transaction can be recorded with a higher-level of privacy. Specifically, the sender of the transaction does not need to be uniquely identified as is the case for on-chain transaction.
Upgradability - the message standard can be more easily upgraded as it does not require core blockchain modifications.
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