dynamic data authentication (DDA)
Dynamic Data Authentication (DDA) is an authentication method for smart cards and credit cards that is designed to protect against misuse and the possibility of cloning.
With dynamic data authentication, the smart card has a private RSA key that can be used to create a dynamic digital signature. Such a signature is valid only for one authentication and includes the card data and unique terminal data in the calculation. This signature is different for each card session because it contains a random number generated by the terminal. The associated public key is stored in a public key certificate signed by the certification authority. The public key can be used to prove the authenticity of the signature.
In addition to the DDA procedure with dynamic data authentication, there is also the static procedure Static Data Authentication( SDA) and the combined procedure Combined Data Authentication( CDA).