Research corpus ScalingBLC-STUDY-0341

Supplant DIFFICULTY opcode with PREVRANDAO

EIP 4399, Supplant DIFFICULTY opcode with PREVRANDAO. This EIP supplants the semantics of the return value of existing DIFFICULTY (0x44) opcode and renames the opcode to PREVRANDAO (0x44).

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Record

Authors: Mikhail Kalinin , Danny Ryan
Date: 2021
Publisher: Mikhail Kalinin , Danny Ryan
Version: Source cited by the 2021 study. The study is the reading. This page does not add a second essay.
Document ID: BLC-STUDY-0341
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

EIP 4399, Supplant DIFFICULTY opcode with PREVRANDAO. This EIP supplants the semantics of the return value of existing DIFFICULTY (0x44) opcode and renames the opcode to PREVRANDAO (0x44).

Where to read

Official source — EIP 4399
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 readingEIP 4399 study
Related paperEIP-4844
Related paperPlasma
Related paperArbitrum

Cite this record

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

Author–date

Kalinin, M., & Ryan, D. (2021). Supplant DIFFICULTY opcode with PREVRANDAO. Mikhail Kalinin , Danny Ryan. https://eips.ethereum.org/EIPS/eip-4399

BibTeX

@techreport{eip43992021,
  title = {Supplant DIFFICULTY opcode with PREVRANDAO},
  author = {Mikhail Kalinin , Danny Ryan},
  year = {2021},
  institution = {Mikhail Kalinin , Danny Ryan},
  url = {https://eips.ethereum.org/EIPS/eip-4399},
  note = {Rights status: Official external source only. Blockchain Lab record: https://blockchainlab.com/research/corpus/papers/eip-4399}
}

RIS

TY  - RPRT
TI  - Supplant DIFFICULTY opcode with PREVRANDAO
AU  - Mikhail Kalinin
AU  - Danny Ryan
PY  - 2021
PB  - Mikhail Kalinin , Danny Ryan
UR  - https://eips.ethereum.org/EIPS/eip-4399
N1  - Rights status: Official external source only
ER  -

CSL-JSON

[
  {
    "type": "report",
    "id": "BLC-STUDY-0341",
    "title": "Supplant DIFFICULTY opcode with PREVRANDAO",
    "author": [
      {
        "literal": "Mikhail Kalinin"
      },
      {
        "literal": "Danny Ryan"
      }
    ],
    "issued": {
      "date-parts": [
        [
          2021
        ]
      ]
    },
    "publisher": "Mikhail Kalinin , Danny Ryan",
    "URL": "https://eips.ethereum.org/EIPS/eip-4399",
    "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