Research corpus Data and agentsBLC-STUDY-0412

CCIP Read—Secure offchain data retrieval

ERC 3668, CCIP Read—Secure offchain data retrieval. Contracts wishing to support lookup of data from external sources may, instead of returning the data directly, revert using OffchainLookup(address sender, string[] urls, bytes callData, bytes4 callbackFunction, bytes extraData).

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Record

Authors: Nick Johnson
Date: 2020
Publisher: Nick Johnson
Version: Source cited by the 2020 study. The study is the reading. This page does not add a second essay.
Document ID: BLC-STUDY-0412
DOI: None recorded
Last reviewed: 1 October 2026
Licence: No licence recorded. Rights status under review.

No hash is published. This build does not store those PDF bytes, so a checksum would be invented. Where a legacy path exists, it points at the Internet Archive copy of the old library.

Direct answer

Where to read

Official source — ERC 3668
Blockchain Lab study, the canonical readingOriginal commentary. Not a transcription of the paper.

Metadata and commentary only. The reading is the study page.

Full text

Full text is not published on this page. Public availability is not a licence to republish a document. Blockchain Lab has not recorded a licence that permits an HTML transcription, a training set, or a retrieval corpus of the paper. Text on this page is Blockchain Lab's own wording, or a pointer to a study that is also Blockchain Lab's wording.

What changed

Status in the source: Final. A reading of the public specification, not a copy of it and not a certification.

Relationships

Canonical readingERC 3668 study
Related paperERC-4337
Related paperChainlink
Related paperThe Graph

Cite this record

These citations point at the source document. They are not a licence to copy it.

Author–date

Johnson, N. (2020). CCIP Read—Secure offchain data retrieval. Nick Johnson. https://eips.ethereum.org/EIPS/eip-3668

BibTeX

@techreport{erc36682020,
  title = {CCIP Read—Secure offchain data retrieval},
  author = {Nick Johnson},
  year = {2020},
  institution = {Nick Johnson},
  url = {https://eips.ethereum.org/EIPS/eip-3668},
  note = {Rights status: Official external source only. Blockchain Lab record: https://blockchainlab.com/research/corpus/papers/erc-3668}
}

RIS

TY  - RPRT
TI  - CCIP Read—Secure offchain data retrieval
AU  - Nick Johnson
PY  - 2020
PB  - Nick Johnson
UR  - https://eips.ethereum.org/EIPS/eip-3668
N1  - Rights status: Official external source only
ER  -

CSL-JSON

[
  {
    "type": "report",
    "id": "BLC-STUDY-0412",
    "title": "CCIP Read—Secure offchain data retrieval",
    "author": [
      {
        "literal": "Nick Johnson"
      }
    ],
    "issued": {
      "date-parts": [
        [
          2020
        ]
      ]
    },
    "publisher": "Nick Johnson",
    "URL": "https://eips.ethereum.org/EIPS/eip-3668",
    "note": "Rights status: Official external source only. Not a licence to republish the paper."
  }
]

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Rights record

Source status: Official source
Use status: Metadata and commentary only. The reading is the study page.
Rights: Official external source only
Training and retrieval: Not permitted from this site. There is no rights-cleared full text to retrieve or to train on.

Rights and licensing Corrections