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The bridge registration process consists of many steps like register a domain, register bridge account, make a record in an asset-store, etc. These steps form an algorithm, that needs to be persistent for everyone who tries to register a bridge. Currently, it's impossible in hard or inconvinient to do Iroha.
Possible solutions
1. Use separate ISI. It's the easiest solution, but it requires Iroha to depend on external entities.
2. Store predefined compositions of ISIs as procedures (or functions) on the Iroha's state. A procedure can be stored as an asset within a separate account with its own rights (permissions).
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