# How Does Blockcerts Revoke a Certificate?

**URL:** <https://community.blockcerts.org/t/how-does-blockcerts-revoke-a-certificate/1105>\
**Category:** Technical\
**Created:** [June 13, 2018, 4:34am UTC](https://community.blockcerts.org/t/how-does-blockcerts-revoke-a-certificate/1105 "2018-06-13T04:34:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jake666](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/jake666/32/258_2.png) [@jake666](https://community.blockcerts.org/u/jake666)\
**Post date:** [June 13, 2018, 4:34am UTC](https://community.blockcerts.org/t/how-does-blockcerts-revoke-a-certificate/1105/1 "2018-06-13T04:34:44Z")

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Hi guys,

One thing I don’t understand is how you can revoke a certificate that has already been written to the blockchain? I.e. if it is immutably written, how can it be undone? Does it just write a different entry to say the original certificate is invalid?

Thanks.

Jake

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**Author:** ![Chris\_J](https://avatars.discourse-cdn.com/v4/letter/c/e480ec/32.png) [@Chris\_J](https://community.blockcerts.org/u/Chris_J)\
**Post date:** [June 13, 2018, 1:08pm UTC](https://community.blockcerts.org/t/how-does-blockcerts-revoke-a-certificate/1105/2 "2018-06-13T13:08:22Z")

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Hey Jake,

Revocation is one of those features that has some complexity, and will evolve going forward. Here is an in depth post about it:

> <https://github.com/WebOfTrustInfo/rebooting-the-web-of-trust-fall2017/blob/master/final-documents/blockcerts-revocation.md>

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**Author:** ![jake666](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/jake666/32/258_2.png) [@jake666](https://community.blockcerts.org/u/jake666)\
**Post date:** [June 14, 2018, 9:10am UTC](https://community.blockcerts.org/t/how-does-blockcerts-revoke-a-certificate/1105/3 "2018-06-14T09:10:31Z")

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Thanks Chris.

From the below, it looks like there is a separate smart contract with a list of credentials that have been revoked. So the original certification will still be on the blockchain, but there is a separate entry on the blockchain for credentials that have been revoked.

Does this imply that once a certificate is revoke it cannot be reinstated?

_\> The individualRevokedList is what allows for individual credentials to be revoked. Anyone can append an item to this list, which can be seen as a claim._

 ![image](https://us1.discourse-cdn.com/flex016/uploads/blockcerts/original/1X/d7bd0ce455cc0a0e8d00ea9459e2029847884295.png)

Jake