Authentication services that include One Time Password and Mobile Signature. One Time Password is used for two-level authentication controls on transactions, especially online banking processes and login transactions. It allows corporate customers to send a single-use password via SMS to consumers when providing authentication on transactions. Mobile Signature enables mobile subscribers to sign electronic documents and transactions with a legally-accepted digital signature using GSM SIM cards. Mobile signature subscribers can verify their personal identity in a digital environment and complete transactions remotely.