A credit card reader is attached to a mobile device to process credit card transactions at the point of sale. A user of the credit card reader slides an authenticator card through the credit card reader to activate the credit card reader. Accordingly, the credit card reader may compare data stored in the authenticator card to an expected value for the data to determine whether the user is authorized to utilize the credit card reader. If there is a match, the credit card reader displays a unique password, known to the user, which the user can use to verify that the credit card reader is authentic. Further, if there is a match, the credit card reader may allow the user to process credit card transactions through the credit card reader.