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An enterprise-grade Java-based, Apache 2.0 licensed Ethereum client https://wiki.hyperledger.org/display/besu
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67 lines
3.4 KiB
67 lines
3.4 KiB
5 years ago
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description: Privacy
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<!--- END of page meta data -->
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# Privacy Groups
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A privacy group is a group of nodes identified by a unique privacy group ID by Orion. Each private transaction is
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stored in Orion with the privacy group ID.
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The Pantheon nodes maintain the public world state for the blockchain and a private state for each privacy group.
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The private states contain data that is not shared in the globally replicated world state. Private transactions read
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and write to the private world state for the privacy group, and read from the public world state.
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## Privacy Types
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Pantheon implements two types of privacy:
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* EEA-compliant privacy - private transactions include `privateFor` as the recipient.
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* Pantheon-extended privacy - private transactions include `privacyGroupId` as the recipient.
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Both privacy types create privacy groups and store private transactions with their privacy group in Orion.
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!!! note
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The Orion nodes are not shown above for clarity only. To send private transactions,
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each Pantheon node must have an associated Orion node.
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### EEA-compliant Privacy
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In our privacy implementation complying with the [EEA Client Specification](https://entethalliance.org/technical-documents/)
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the group of nodes specified by `privateFrom`and `privateFor` form a privacy group and are given a unique
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privacy group ID by Orion.
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!!! example
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The diagram above illustrates two privacy groups enabling:
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* A, B, and C to send transactions that are private from D
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* A, C, and D to send transactions that are private from B
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Using EEA-compliant privacy, to send private transactions between A, B, and C, A initialises a contract in a private transaction with
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B and C specified as the `privateFor` and A specified as the `privateFrom`. Initialising the contract
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creates a privacy group consisting of A, B, and C. For the ABC private state to remain consistent,
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A, B, and C must be included on transactions (as either `privateFrom` or `privateFor`) even if they are
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between two of the three parties.
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To send private transactions between A, C, and D, C initialises a different contract in a private transaction with
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A and D specified as the `privateFor` and C specified as the `privateFrom`. Initialising the contract
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creates a privacy group consisting of A, C, and D. For the ACD private state to remain consistent,
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A, C, and D must be included on transactions (as either `privateFrom` or `privateFor`) even if they are
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between two of the three parties.
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### Pantheon-extended Privacy
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In our extended privacy implementation, a privacy group is created using [`priv_createPrivacyGroup`](../../Reference/Pantheon-API-Methods.md#priv_createprivacygroup)
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and private transactions sent to the privacy group ID.
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!!! example
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Using the same privacy groups as above.
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Using Pantheon-extended privacy, to send private transactions between A, B, and C, A creates a privacy
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group consisting of A, B, and C. The privacy group ID is specified when sending private transactions and
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A, B, and C are recipients of all private transactions sent to the privacy group.
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To send private transactions between A, C, and D, A creates a privacy group consisting of A, C, and D.
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The privacy group ID of this group is specified when sending private transactions with A, C, and D
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as recipients.
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