A method of authenticating and encrypting a client-server communication is provided. Two one-time passwords (OTP1 and OTP2) are generated from a cryptographic token. An encryption key (K_ENC) and a MAC key (K_MAC) are generated based on OTP2. The client data are prepared and protected using K_ENC and K_MAC. A request message is sent from the client to the server, and contains the protected client data, a cryptographic token identifier and OTP1. OTP1 is validated at the server, and OTP2 is generated at the server upon successful validation. K_ENC and K_MAC are derived from OTP2 at the server. The request message is processed and result data is generated. The result data is encrypted using K_ENC and a digest is created using K_MAC. The encrypted result data is sent to the client, and is decrypted using K_ENC and the authenticity of the result data is verified using K_MAC.