# Revocation

Revocation is the process of invalidating a claim. For example, if a claim is used to prove that a person is resident in a country, and the person moves to another country, the claim can be revoked.

This is done by adding the claim to the revocation tree. The revocation tree is a Merkle Tree that contains all the claims that have been revoked. The root of the revocation tree is stored in the identity state.

To revoke a claim, the revocation nonce of the claim must be added to the revocation tree. The revocation nonce is a number that is added to the claim data structure when it is created.

    // revocation nonce of the claim to be revoked
revocationNonce := uint64(1909830690)

// add the revocation nonce to the revocation tree