Reproducible benchmark evidence
Evidence checker benchmark: 16 inputs and actual reports
This register documents 16 public-safe controlled inputs across provenance, metadata, processing, and C2PA integrity. Every case has an exact SHA-256, dated report JSON, report hash, run environment, and an evidence review record.
4
Camera originals
Baseline, stripped, recompressed, and converted copies.
4
AI original exports
Marker and metadata conditions without a binary-origin promise.
4
Processed copies
Screenshots and platform-like transformations that weaken provenance.
4
C2PA integrity
Trusted, untrusted, binding-mismatch, and marker-only states.
Review status
The evidence bundle and maintainer review are complete. Each case records its review method, date, and evidence limitations. Download the complete manifest JSON to audit every binding.
Evidence case register
Camera metadata baseline
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- 2ac758e9ea4a07a57539066016b6f3bde2b49e114595cb1b175dd504c5e70b04
- Preparation
- Deterministic project-owned RGB fixture saved once as JPEG quality 92 with synthetic test-camera EXIF.
- Observed result
- camera_like · absent
- Report SHA-256
- 7a0b4cc43e83371beca302270e86b51985e3a10aabd2faa4ab892cb9e20ee327
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The image has camera-like supporting evidence and no strong AI provenance marker was detected.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Camera metadata removed
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- 317c74b99452456a53cf9fb16ae7542defe4c2b55dead74cd0d2eee48553fbcf
- Preparation
- Decoded camera-01 pixels and saved as JPEG quality 92 without EXIF.
- Observed result
- camera_like · absent
- Report SHA-256
- bbf2dab92d8872c5871e6101f3d2ccae1d239d01b83ea88cdfd3b4fd19ba49f7
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The image has camera-like supporting evidence and no strong AI provenance marker was detected.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Camera image recompressed once
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- 3c22bbb92e0f3476eb5dff1361a7d749310521e6fcfc6b0322f7c2dbf26bc7a7
- Preparation
- Decoded camera-01 and recompressed once as JPEG quality 72 while retaining its test EXIF.
- Observed result
- camera_like · absent
- Report SHA-256
- 7dce0d5801b7d393d6a0b8fa1aa8de36d3280449b8373bc1f25f7602765a30c3
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The image has camera-like supporting evidence and no strong AI provenance marker was detected.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Camera image converted to WebP
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- 728f2ec3f7f596cbdbe73fbdab04f19e0f57b4e372fb6f495e477bd73e0e8f3f
- Preparation
- Decoded camera-01 and converted to WebP quality 82 while retaining its test EXIF.
- Observed result
- camera_like · absent
- Report SHA-256
- 7ee4be633f189b0b6fd88470450c12fe02f8c6ecc9fcaa168c9f76151a63ffb1
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The image has camera-like supporting evidence and no strong AI provenance marker was detected.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
AI provenance-marker baseline
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- 708d09c980299389c8a8d2553944f88460d610470dc6a38289baff8d69ed9858
- Preparation
- Project-owned PNG with explicit OpenAI, trainedAlgorithmicMedia, and c2pa marker-only text chunks.
- Observed result
- openai_marker_unverified · verifier_unavailable_marker_detected
- Report SHA-256
- 40e8bc54cd73157fc6e6efd8c50658fddaa5f9224b3386508d42023355253918
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: OpenAI/C2PA-style markers were found, but the C2PA signature has not been verified in this runtime.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
AI marker with metadata retained
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- 387d665a504caed06e3bfe602a116af8b76bc32c3ea4ba4d86df0cebc57f21a1
- Preparation
- Project-owned PNG with an XMP-shaped text chunk retaining OpenAI, trainedAlgorithmicMedia, and c2pa strings.
- Observed result
- openai_marker_unverified · verifier_unavailable_marker_detected
- Report SHA-256
- 1810175bc6d9e88dd7589262ad39f5d09d59e81e30e0256b368ad82358bb5265
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: OpenAI/C2PA-style markers were found, but the C2PA signature has not been verified in this runtime.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
AI-style XMP marker fixture
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- ed8e1a899a6abb500fa0c682a9227aa83d9a8f79308970458d613b7f0f9fb56d
- Preparation
- Project-owned JPEG with a controlled XMP-shaped AI marker appended after EOI; no signed manifest.
- Observed result
- other_ai_provenance_marker · absent
- Report SHA-256
- 6307821372cd7636567f955145a6be02858df7d2572cc145946889c726ed6149
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: AI-related provenance markers were found, but they are not a definitive attribution by themselves.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
AI-style byte marker fixture
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- 2932be92998a9a9b39eedcf6234fcee92563334f004dcd2b96eadc730cacd8b8
- Preparation
- Project-owned WebP with controlled XMP and trainedAlgorithmicMedia byte markers appended after the RIFF payload.
- Observed result
- other_ai_provenance_marker · absent
- Report SHA-256
- 4b417e73571911dbe37bb9192a73747fab6c02178490dd63fd40d85ff07f621b
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: AI-related provenance markers were found, but they are not a definitive attribution by themselves.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Screenshot-style metadata loss
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- baf98a932dd0057b6aae3f4359bb94a31fa411fb336bafbf25e025c487af5fe3
- Preparation
- Decoded ai-01 pixels and saved as a new PNG without source text chunks, modeling screenshot metadata loss.
- Observed result
- frequency_suspicious · absent
- Report SHA-256
- 3b5314d56e79eb0112aadcfc19b2d8d519798f3b066a824bb60f48ececf2902d
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The frequency score is above the configured reference threshold, which is a supportive signal only.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Social upload-style recompression
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- e629a515442e1f1db4cd6668b560db03a130f1e9360bbc9e52b6f70d54705be1
- Preparation
- Decoded ai-03 pixels and recompressed as JPEG quality 58, dropping the appended marker.
- Observed result
- camera_like · absent
- Report SHA-256
- a32ae4234b5a71f71cacae3479a4cfeb2e5b347795ea1735c63b913f617d1dab
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The image has camera-like supporting evidence and no strong AI provenance marker was detected.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Metadata-stripped copy
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- c291b5a431bf51cab21d7a94b7fc89d406a1aaccd97952c71b8bde6e4c8129e6
- Preparation
- Decoded camera-01 pixels and saved as JPEG quality 88 without EXIF.
- Observed result
- camera_like · absent
- Report SHA-256
- a26f8b192b2b6a29d4c8f32f714794a0adda18137081b77093b0af8d0b2d37fc
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The image has camera-like supporting evidence and no strong AI provenance marker was detected.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Resized and converted copy
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- bb9df1dbbf57919d13cbb579cd24d4b64aa13a1cdd0afd56c5600e2a7ecfd1e3
- Preparation
- Decoded ai-02 pixels, resized to 320x240, and saved as WebP quality 70 without metadata.
- Observed result
- frequency_suspicious · absent
- Report SHA-256
- 8c6809f4200c3f1b3bf669e41620b0ea82c40b4fae697607d35de69efc60ab99
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: The frequency score is above the configured reference threshold, which is a supportive signal only.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Trusted manifest expectation
Maintainer reviewed- Source and license
- Content Authenticity Initiative c2patool v0.26.67 distribution sample; dual Apache-2.0/MIT project · Apache-2.0/MIT upstream
- Input SHA-256
- 5f57bc22ad54aab1228874e831a6feb5514e5875307945c4e4b11aae6c53e8b7
- Preparation
- Unmodified c2patool v0.26.67 sample/C.jpg, evaluated with its sample end-entity allowed list.
- Observed result
- other_ai_provenance_marker · valid_signature
- Report SHA-256
- 5c60990a429967fd19c61de0ff7c4dd201c2fc1a708b2cd8175fe68f97f0e741
- Run environment
- 2026-08-03 · c2patool 0.26.67 · End-entity allow list SHA-256 7973400b5b75c3f8dd1f1c76f18d0c862842cbedeeb13b1fbb71e1e541d3f5f0
Conclusion: The manifest signature and asset binding validate under the recorded benchmark allow-list policy.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Manifest present but trust unresolved
Maintainer reviewed- Source and license
- Content Authenticity Initiative example-assets; MIT License · MIT
- Input SHA-256
- bdc5c19d4211d9c9f9f8dce5bf4e4dec29e9b32e308ff12a60979481e928154f
- Preparation
- Unmodified CAI example-assets Firefly_tabby_cat.jpg, evaluated without a configured signer trust list.
- Observed result
- other_ai_provenance_marker · verifier_error_marker_detected
- Report SHA-256
- c34f7b6ef510baeadc247e47fcffd6dbb946a300efc94c3e7c26db43ac3b6371
- Run environment
- 2026-08-03 · c2patool 0.26.67 · No trust anchors or signer allow list configured.
Conclusion: The signature is intact, but the signer is not trusted under this case's empty trust policy.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
Asset-binding mismatch expectation
Maintainer reviewed- Source and license
- Content Authenticity Initiative c2patool v0.26.67 distribution sample; dual Apache-2.0/MIT project · Apache-2.0/MIT upstream
- Input SHA-256
- 49058d24bf9f02312833b17db4cc1162dfc70c6b1aef36a428fcb1ea0afe4033
- Preparation
- Derived from c2pa-01 by flipping bit 0 of JPEG entropy byte offset 952; file remains decodable.
- Observed result
- other_ai_provenance_marker · asset_hash_mismatch
- Report SHA-256
- a45849991305f391c8fb25230afffb9626bc7f5f7e75cba3baa0f5b666979b96
- Run environment
- 2026-08-03 · c2patool 0.26.67 · End-entity allow list SHA-256 7973400b5b75c3f8dd1f1c76f18d0c862842cbedeeb13b1fbb71e1e541d3f5f0
Conclusion: The verifier found a signed-manifest asset-binding mismatch; this controlled mutation is detected.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
No manifest / marker-only expectation
Maintainer reviewed- Source and license
- Img2det project-owned controlled fixture · Project-owned
- Input SHA-256
- a1d8bca10fec13797bb32c1c39712c4c8311c3eed9a67dbb70e013e5772b0c41
- Preparation
- Project-owned PNG containing a literal c2pa text marker but no C2PA/JUMBF manifest.
- Observed result
- other_ai_provenance_marker · verifier_unavailable_marker_detected
- Report SHA-256
- e2489f9e4dafbe6c33ae63dcae4f53e44fb89712582d652c150761af63fb9ac8
- Run environment
- 2026-08-03 · not invoked · No C2PA verifier invoked for this controlled non-C2PA/marker-only case.
Conclusion: AI-related provenance markers were found, but they are not a definitive attribution by themselves.
Limit: Controlled fixture result only; it does not measure real-world prevalence or detector accuracy.
User uploads are never included. See the methodology and editorial policy for review rules.