Updated 2020-03-20

Creating and sending private transactions

Create and send private transactions using:

All private transaction participants must be online for a private transaction to be successfully distributed. If any participants are offline when submitting the private transaction, the transaction is not attempted and you must resubmit the transaction.

Note

Private transactions either deploy contracts or call contract functions. Ether transfer transactions cannot be private.

Tip

priv_call returns the same information for private contracts as eth_call does for non-private contracts.

eea_sendRawTransaction

eea_sendRawTransaction distributes the private transaction to the participating nodes, and signs and submits the privacy marker transaction, as described in Private Transaction Processing.

priv_distributeRawTransaction

priv_distributeRawTransaction distributes the private transaction to the participating nodes but does not sign and submit the privacy marker transaction.That is, priv_distributeRawTransaction performs steps 1 to 5 of Private Transaction Processing.

When using priv_distributeRawTransaction instead of eea_sendRawTransaction, send the enclave key returned by priv_distributeRawTransaction as the data in a public Ethereum transaction. That is, you sign and submit the privacy marker transaction yourself.

Signing and submitting the privacy marker transaction instead of having it signed by the Besu node when processing the private transaction enables greater control over the signing of the privacy marker transaction.

Warning

If the privacy marker transaction is not sent after distributing the private transaction, the distributed private transaction is not executed and the private states are not updated.

Example

Distribute private transaction using priv_distributeRawTransaction:

{
  "jsonrpc":"2.0",
  "method":"priv_distributeRawTransaction",
  "params":["0xf90198808203e8832dc6c08080b8fb608060405234801561001057600080fd5b5060dc8061001f6000396000f3006080604052600436106049576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff1680633fa4f24514604e57806355241077146076575b600080fd5b348015605957600080fd5b50606060a0565b6040518082815260200191505060405180910390f35b348015608157600080fd5b50609e6004803603810190808035906020019092919050505060a6565b005b60005481565b80600081905550505600a165627a7a723058202bdbba2e694dba8fff33d9d0976df580f57bff0a40e25a46c398f8063b4c003600291ba05393543d483654fd01d9ee818cddfc7527dd6e13e6ef7b45a61e2ca13ffb6b70a0452338873862803ffe04056aea98cd0e3417ff971dcb384e54fce8ca1756a665a09de8260dc3763f8383a6a9ffe96909d36cd3ff4c346e3846a6467c50feaf0119e1a0839f41993789227ec721c9eaf1541683287fa436ef6edd9ec8fd088bad1a0c3c8a72657374726963746564"],
  "id":1
}

Enclave key is returned by priv_distributeRawTransaction:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0xfd0d90ab824574abc19c0776ca0210e764561d0ef6d621f2bbbea316eccfe56b"
}

Send privacy marker transaction using eth_sendTransaction with EthSinger:

{
  "jsonrpc":"2.0",
  "method":"eth_sendTransaction",
  "params":[{
    "from": "0xfe3b557e8fb62b89f4916b721be55ceb828dbd73",
    "data": "0xfd0d90ab824574abc19c0776ca0210e764561d0ef6d621f2bbbea316eccfe56b",
    "gas": "0x2E1800",
    "gasPrice": "0x9184e72a000"
  }],
  "id":1
}

Private transaction nonce

Besu maintains separate private states for each privacy group so the nonce for an account is specific to the privacy group. That is, the nonce for account A for privacy group ABC is different to the nonce for account A for privacy group AB. Use priv_getTransactionCount or priv_getEeaTransactionCount to get the nonce for an account for the specified privacy group.

Note

If sending more than 1 transaction for mining in the same block (that is, you are not waiting for the transaction receipt), you must calculate the private transaction nonce outside Besu.

EEA-compliant or Besu-extended Privacy

To create an EEA-compliant private transaction, specify privateFor when creating the signed transaction passed as an input parameter to eea_sendRawTransaction.

To create a Besu-extended private transaction, specify a privacyGroupId when creating the signed transaction passed as an input parameter to eea_sendRawTransaction.

Unsigned and unencoded private transactions

The eea_sendRawTransaction parameter is a signed RLP-encoded private transaction. Shown below are examples of unsigned and unencoded private transactions to create a contract.

Unencoded and unsigned EEA-compliant private transaction

{
  "to": null,
  "from": "0xfe3b557e8fb62b89f4916b721be55ceb828dbd73",
  "gas": "0x7600",
  "gasPrice": "0x0",
  "data": "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",
  "nonce": "0x0",
  "privateFrom": "negmDcN2P4ODpqn/6WkJ02zT/0w0bjhGpkZ8UP6vARk=",
  "privateFor": ["g59BmTeJIn7HIcnq8VQWgyh/pDbvbt2eyP0Ii60aDDw=","6fg8q5rWMBoAT2oIiU3tYJbk4b7oAr7dxaaVY7TeM3U="],
  "restriction": "restricted"
}

Unencoded and unsigned Besu-extended private transaction

{
  "to": null,
  "from": "0xfe3b557e8fb62b89f4916b721be55ceb828dbd73",
  "gas": "0x7600",
  "gasPrice": "0x0",
  "data": "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",
  "nonce": "0x0",
  "privateFrom": "negmDcN2P4ODpqn/6WkJ02zT/0w0bjhGpkZ8UP6vARk=",
  "privacyGroupId": "kAbelwaVW7okoEn1+okO+AbA4Hhz/7DaCOWVQz9nx5M=",
  "restriction": "restricted"
}

Tip

The example directory in the web3js-eea client library contains examples of signing and encoding private transactions.