ConfirmDevice function not working with React JS code with serverless

Hello,

I understand that you are facing an error (InvalidParameterException: Found negative value for salt or password verifier) while trying to call the ConfirmDevice API and you want some insight into the PasswordVerifier formula.

This error usually occurs in the following use cases:

1→ Using old version of Amplify. If you are using Amplify and an old version, you might run into this error. Further details can be read here [2] on this Github issue.

2→ The calculated password verifier value/ salt value is incorrect. With the DeviceGroupKey and DeviceKey, you would have to use the Secure Remote Password (SRP) protocol to create a secret. This generates a salt and a password verifier. The formula for password verifier would be as follows: => PasswordVerifier = g( SHA256_HASH(salt + FULL_PASSWORD) ) (mod N)

Note: for the values of g and N refer the documentation

[+] https://github.com/aws-amplify/amplify-js/blob/master/packages/amazon-cognito-identity-js/src/AuthenticationHelper.js#L57

The article below discusses the same issue and has an elaborate details regarding the issue. Please go through the article for further insight into the issue.

[+] https://repost.aws/questions/QUp7x1PyHdSC6wKCAkmKZYGA/aws-cognito-deviceconfirm-sending-invalidparameterexception-found-negative-value-for-salt-or-password-verifier

That being said, to further look into this issue more closely, if you would like to do a resource based troubleshooting, please raise a support case with AWS for further information. If a support case has already been created please be assured that we will get back to you and assist you in the best way possible.

[+] https://console.aws.amazon.com/support/home#/case/create