{"id":"GHSA-7f6p-phw2-8253","aliases":["GO-2024-3288"],"status":"published","title":"Taurus multi-party-sig has OT-based ECDSA protocol implementation flaws","description":"Coinbase researchers reported 2 security issues in our implementation of the oblivious transfer (OT) based protocol [DKLS](https://eprint.iacr.org/2018/499.pdf):\n\n### 1. Secret share recovery attack\n\nIf the base OT setup of the protocol is reused for another execution of the OT extension, then a malicious participant can extract a bit of the secret of another participant. By repeating the execution they can eventually recover the whole secret.\n\nTherefore, unlike our comments suggested, you **must not reuse an OT setup** for multiple protocol executions. \n\nWe're adding a warning in the code:\n\nhttps://github.com/taurushq-io/multi-party-sig/blob/9e4400fccee89be6195d0a12dd0ed052288d5040/internal/ot/extended.go#L114\n\n### 2. Invalid security proof due to incorrect operator\n\nThe original 2018 version of the DKLS had a typo in the OT extension protocol when computing the check value in the OT extension: the paper noted a XOR whereas it should be a field multiplication. This erroneous behavior was implemented [in our code](https://github.com/taurushq-io/multi-party-sig/blob/4d84aafb57b437da1b933db9a265fb7ce4e7c138/internal/ot/extended.go#L188). \n\nThe proof of security fails in this case. No concrete attack is known, however.\n\nThe [2023 update](https://eprint.iacr.org/2018/499.pdf) of the DKLS paper reported that typo and updated the protocol definition.\n\n~As of 20241124, patching is in progress (branch [otfix](https://github.com/taurushq-io/multi-party-sig/tree/otfix)), but not merged to the main branch yes as the tests fail to pass. We're troubleshooting the issue and will merge into the main branch when it's resolved.~\n\nAs of 20250128, a patched version is available in https://github.com/taurushq-io/multi-party-sig/releases/tag/v0.7.0-alpha-2025-01-28, thanks to https://github.com/taurushq-io/multi-party-sig/pull/119.\n\n### Workarounds\n\nDo not reuse an OT setup in the event that an abort is detected, to eliminate the secret recovery attack.\n  \n\n### Credits\n\nThanks to the Coinbase researchers Yi-Hsiu Chen and Samuel Ranellucci for discovering these issues and providing a comprehensive write-up. Thank you to Yehuda Lindell for coordinating the disclosure.\nThanks to Jay Prakash for clarifying the risk of the base setup reuse.\nThanks to @cronokirby for writing the corrected code.","facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"published":"2024-11-25T15:11:11Z","modified":"2026-03-03T04:56:02Z","fixes":[{"ecosystem":"Go","package":"github.com/taurusgroup/multi-party-sig","fixed_in":["0.7.0-alpha-2025-01-28"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/taurusgroup/multi-party-sig","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"0.6.0-alpha-2021-09-21"},{"fixed":"0.7.0-alpha-2025-01-28"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/taurusgroup/multi-party-sig","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.7.0-alpha-2025-01-28"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/taurusgroup/multi-party-sig","ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}]}],"references":[{"url":"https://github.com/taurushq-io/multi-party-sig/security/advisories/GHSA-7f6p-phw2-8253","tags":["web","advisory"]},{"url":"https://eprint.iacr.org/2018/499.pdf","tags":["web"]},{"url":"https://github.com/taurushq-io/multi-party-sig/blob/4d84aafb57b437da1b933db9a265fb7ce4e7c138/internal/ot/extended.go#L188","tags":["web"]},{"url":"https://github.com/taurushq-io/multi-party-sig/blob/9e4400fccee89be6195d0a12dd0ed052288d5040/internal/ot/extended.go#L114","tags":["web"]},{"url":"https://github.com/taurushq-io/multi-party-sig/tree/otfix","tags":["web"]},{"url":"https://github.com/advisories/GHSA-7f6p-phw2-8253"},{"url":"https://github.com/taurushq-io/multi-party-sig","tags":["package"]}],"sources":{"ghsa":[{"id":"GHSA-7f6p-phw2-8253","title":"Taurus multi-party-sig has OT-based ECDSA protocol implementation flaws","description":"Coinbase researchers reported 2 security issues in our implementation of the oblivious transfer (OT) based protocol [DKLS](https://eprint.iacr.org/2018/499.pdf):\n\n### 1. Secret share recovery attack\n\nIf the base OT setup of the protocol is reused for another execution of the OT extension, then a malicious participant can extract a bit of the secret of another participant. By repeating the execution they can eventually recover the whole secret.\n\nTherefore, unlike our comments suggested, you **must not reuse an OT setup** for multiple protocol executions. \n\nWe're adding a warning in the code:\n\nhttps://github.com/taurushq-io/multi-party-sig/blob/9e4400fccee89be6195d0a12dd0ed052288d5040/internal/ot/extended.go#L114\n\n### 2. Invalid security proof due to incorrect operator\n\nThe original 2018 version of the DKLS had a typo in the OT extension protocol when computing the check value in the OT extension: the paper noted a XOR whereas it should be a field multiplication. This erroneous behavior was implemented [in our code](https://github.com/taurushq-io/multi-party-sig/blob/4d84aafb57b437da1b933db9a265fb7ce4e7c138/internal/ot/extended.go#L188). \n\nThe proof of security fails in this case. No concrete attack is known, however.\n\nThe [2023 update](https://eprint.iacr.org/2018/499.pdf) of the DKLS paper reported that typo and updated the protocol definition.\n\n~As of 20241124, patching is in progress (branch [otfix](https://github.com/taurushq-io/multi-party-sig/tree/otfix)), but not merged to the main branch yes as the tests fail to pass. We're troubleshooting the issue and will merge into the main branch when it's resolved.~\n\nAs of 20250128, a patched version is available in https://github.com/taurushq-io/multi-party-sig/releases/tag/v0.7.0-alpha-2025-01-28, thanks to https://github.com/taurushq-io/multi-party-sig/pull/119.\n\n### Workarounds\n\nDo not reuse an OT setup in the event that an abort is detected, to eliminate the secret recovery attack.\n  \n\n### Credits\n\nThanks to the Coinbase researchers Yi-Hsiu Chen and Samuel Ranellucci for discovering these issues and providing a comprehensive write-up. Thank you to Yehuda Lindell for coordinating the disclosure.\nThanks to Jay Prakash for clarifying the risk of the base setup reuse.\nThanks to @cronokirby for writing the corrected code.\n\n\n","status":"published","published":"2024-11-25T15:11:11Z","modified":"2025-01-28T18:06:15Z","updated_at":"2026-11-02T14:38:28.945236Z"}],"osv":[{"id":"GHSA-7f6p-phw2-8253","title":"Taurus multi-party-sig has OT-based ECDSA protocol implementation flaws","description":"Coinbase researchers reported 2 security issues in our implementation of the oblivious transfer (OT) based protocol [DKLS](https://eprint.iacr.org/2018/499.pdf):\n\n### 1. Secret share recovery attack\n\nIf the base OT setup of the protocol is reused for another execution of the OT extension, then a malicious participant can extract a bit of the secret of another participant. By repeating the execution they can eventually recover the whole secret.\n\nTherefore, unlike our comments suggested, you **must not reuse an OT setup** for multiple protocol executions. \n\nWe're adding a warning in the code:\n\nhttps://github.com/taurushq-io/multi-party-sig/blob/9e4400fccee89be6195d0a12dd0ed052288d5040/internal/ot/extended.go#L114\n\n### 2. Invalid security proof due to incorrect operator\n\nThe original 2018 version of the DKLS had a typo in the OT extension protocol when computing the check value in the OT extension: the paper noted a XOR whereas it should be a field multiplication. This erroneous behavior was implemented [in our code](https://github.com/taurushq-io/multi-party-sig/blob/4d84aafb57b437da1b933db9a265fb7ce4e7c138/internal/ot/extended.go#L188). \n\nThe proof of security fails in this case. No concrete attack is known, however.\n\nThe [2023 update](https://eprint.iacr.org/2018/499.pdf) of the DKLS paper reported that typo and updated the protocol definition.\n\n~As of 20241124, patching is in progress (branch [otfix](https://github.com/taurushq-io/multi-party-sig/tree/otfix)), but not merged to the main branch yes as the tests fail to pass. We're troubleshooting the issue and will merge into the main branch when it's resolved.~\n\nAs of 20250128, a patched version is available in https://github.com/taurushq-io/multi-party-sig/releases/tag/v0.7.0-alpha-2025-01-28, thanks to https://github.com/taurushq-io/multi-party-sig/pull/119.\n\n### Workarounds\n\nDo not reuse an OT setup in the event that an abort is detected, to eliminate the secret recovery attack.\n  \n\n### Credits\n\nThanks to the Coinbase researchers Yi-Hsiu Chen and Samuel Ranellucci for discovering these issues and providing a comprehensive write-up. Thank you to Yehuda Lindell for coordinating the disclosure.\nThanks to Jay Prakash for clarifying the risk of the base setup reuse.\nThanks to @cronokirby for writing the corrected code.\n\n\n","status":"published","published":"2024-11-25T15:11:11Z","modified":"2025-01-28T18:06:15Z","updated_at":"2026-11-02T15:46:41.002603Z"},{"id":"GO-2024-3288","title":"Taurus multi-party-sig has OT-based ECDSA protocol implementation flaws in github.com/taurusgroup/multi-party-sig","description":"Taurus multi-party-sig has OT-based ECDSA protocol implementation flaws in github.com/taurusgroup/multi-party-sig","status":"published","published":"2024-11-27T19:16:39Z","modified":"2026-03-03T04:56:02.578799Z","updated_at":"2026-11-02T15:47:01.453823Z"}]}}