If you are trying to check your refund status, this is the information needed to verify the correct taxpayer's account.
Please see IRS Privacy Notice:
*Privacy Notice*
"We ask for your personal information, including your social security number, so that we can verify who you are and access the correct taxpayer account. This allows us to provide you with the tax information you request.
By submitting this information, you certify that you are the person identified. Use of this system to access another person's information may result in civil and criminal penalties.
We use and retain your personal information only for this purpose and only long enough to complete the transaction, ensure the security of our systems, and as authorized by law. We do not share it other than as provided by law. If you choose not to provide it, we will not be able to fully comply with your request.
The IRS requires Transport Layer Security (TLS) encryption be enabled to ensure the security of your personal tax information. Please ensure your browser has the appropriate security settings configured to ensure proper operation of this online service."
https://www.irs.gov/privacy-disclosure/irs-privacy-policy
