EdDSA: the requested test vectors for SigGen mode has unexpected 'context' and 'contextLength' parameters in some tests

[almau]

The RFC 8032 defines various parameter sets for the EdDSA algorithm. The need for providing the "context" is applicable solely to Ed25519ctx. The RFC also specifies that "the context (if present at all) MUST be empty" for Ed25519.

The following registration JSON object used to report to the demo ACVP server the EdDSA sigGen mode capabilities without supporting the "context":

{
    "algorithm": "EDDSA",
    "mode": "sigGen",
    "revision": "1.0",
    "prereqVals": [
        {
            "algorithm": "SHA",
            "valValue": "same"
        }
    ],
    "pure": true,
    "preHash": false,
    "contextLength": [0],
    "curve": [
        "ED-25519",
        "ED-448"
    ]
},

A test vector request is generated by the demo server upon accepting such settings. The request contains several tests, some of which simply have the "message" value, and others which also have the values "message", "context" and "contextLength" = 1.

[
   {
    "vsId": 2471370,
    "algorithm": "EDDSA",
    "mode": "sigGen",
    "revision": "1.0",
    "isSample": true,
    "testGroups": [
        {
            "tgId": 1,
            "testType": "AFT",
            "curve": "ED-25519",
            "preHash": false,
            "tests": [
                {
                    "tcId": 1,
                    "message": "C19FF187A64E7AF49D492EDAC284EF1690FF85F82757D0FE77AE2B5F1B356213A526C1D9B34BE5CA730CBB2DD3D43C381807B422ED01478278A4D38C18EE00587601AFFFBC071E442173F96FDA48A24B3A444E1B8DD81555267DE0D290073E6D7B9575761F777D662341FA03566D0059776393575C7BEDEC78CF763A6E41861C"
                },
                {...}
            ]
        },
        {
            "tgId": 2,
            "testType": "AFT",
            "curve": "ED-448",
            "preHash": false,
            "tests": [
                {
                    "tcId": 11,
                    "message": "C0192F9CCCA0B148517A373D1FA58BD25025C2E8A3213F8DF8B943B01F34A917C2D687B62743F3A547F8F812E381A135772F712D9655B748D056DFBF46F841498D1BBEC0DA0302C252593E5A6910E4D77889A9607D3732819762BA2A0545FE85536223C8581ABF218FEF64C9D64FAA8B80E505457E94ABB0E316DB9A2592B2B7",
                    "context": "E1",
                    "contextLength": 1
                },
                {...}
            ]
        },
        {
            "tgId": 3,
            "testType": "BFT",
            "curve": "ED-25519",
            "preHash": false,
            "tests": [
                {
                    "tcId": 21,
                    "message": "9420C1BA"
                },
                {...}
            ]
        }
        ]
    }
]

The specified configuration was implemented in the hotfix update released on May 23, 2024 in response to the issue #1501

No "context" or "contextLength" values need to be included in any of the test cases in the expected test vector request. An empty "context" with "contextLength" = 0 could be included as an alternative to represent the test with solely the "message" value.

Test 11 in the request, which is given as an example, needs to be:

{
    "tcId": 11,
    "message": "C0192F9CCCA0B148517A373D1FA58BD25025C2E8A3213F8DF8B943B01F34A917C2D687B62743F3A547F8F812E381A135772F712D9655B748D056DFBF46F841498D1BBEC0DA0302C252593E5A6910E4D77889A9607D3732819762BA2A0545FE85536223C8581ABF218FEF64C9D64FAA8B80E505457E94ABB0E316DB9A2592B2B7"
}

or alternatively:

{
    "tcId": 11,
    "message": "C0192F9CCCA0B148517A373D1FA58BD25025C2E8A3213F8DF8B943B01F34A917C2D687B62743F3A547F8F812E381A135772F712D9655B748D056DFBF46F841498D1BBEC0DA0302C252593E5A6910E4D77889A9607D3732819762BA2A0545FE85536223C8581ABF218FEF64C9D64FAA8B80E505457E94ABB0E316DB9A2592B2B7",
    "context": "",
    "contextLength": 0
}

[almau]

The latest build, v1.1.0.36, fixes the reported bug.
The zero-length context was validated in session 548075.

[livebe01]

Great. Thanks for letting us know!

[livebe01]

The fix for this issue has been deployed to ACVTS Prod as part of the v1.1.0.36 release.