3DS ReferenceProtocol & field guide

EMV 3-D Secure · Core specification 2.3.1.1

SDK Ephemeral Public Key (Qc)sdkEphemPubKey

SDK Ephemeral Public Key (Qc) in Authentication Request (AReq).

Source edition: Core 2.3.1.1 · Type: Object · Length: Variable, maximum 256 · Maximum length: 256

Baseline in AReq Required

Varies by context. Requirement or applicability varies by channel or message category. Select a specific context to resolve it. Usage and conditions ↓

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Usage in AReq

Public key component of the ephemeral key pair generated by the 3DS SDK and used to establish session keys between the 3DS SDK and ACS. In AReq, this data element is present as its own object. In ARes, this data element is contained within the ACS Signed Content JWS Object. See Section 6.2.3.1 for additional detail.

Conditional inclusion — source text

For the ARes message, see ACS Signed Content.

Format and scope

Type: Object · Length: Variable, maximum 256 · Maximum length: 256

Source components: 3DS SDK. Channels: 01-APP. Categories: 01-PA, 02-NPA.

Object members

Nested presence rules apply when the parent is supplied. Consult the source for full conditions.

sdkEphemPubKey — SDK Ephemeral

sdkMaxTimeout — SDK Maximum

sdkReferenceNum — SDK Reference

EMV_3DS_CoreSpec_v2.3.1.1_20230530.pdf, Table A.1, PDF pages 281

Scoped FAQ qualifications

  • FAQ 27 — Applicable object-bearing protocol versions

    Only when the parent JSON object is present

    Evaluate nested presence conditions when the parent object is present. In multiTransaction, merchantList is required when the object is supplied; merchantAmount remains optional.

    EMVCo_3DS_Specification_FAQs_8-April-2026.pdf, page 9

  • FAQ 73 — Applicable object-bearing protocol versions

    An optional or conditionally optional field is sent empty

    An empty optional field produces error 203 under Req 309. When the empty JSON object contains mandatory data, error 201 may be returned.

    EMVCo_3DS_Specification_FAQs_8-April-2026.pdf, page 23

Transaction context

This reference covers the published source edition. Use the explorer to inspect this field and any applicable transaction conditions. Scheme programme requirements are not inferred from the protocol edition.

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Sources and related references

EMV_3DS_CoreSpec_v2.3.1.1_20230530.pdf, Table A.1, PDF pages 281

Source review status: carried-forward. Carried-forward material has not acquired a new verification claim.

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