Methods and systems are provided for efficient and secure “Machine-to-Machine” (M2M) between modules and servers. A module can communicate with a server by accessing the Internet, and the module can include a sensor and/or actuator. The module and server can utilize public key infrastructure (PKI) such as public keys to encrypt messages. The module and server can use private keys to generate digital signatures for datagrams sent and decrypt messages received. The module can internally derive pairs of private/public keys using cryptographic algorithms and a set of parameters. A server can use a shared secret key to authenticate the submission of derived public keys with an associated module identity. For the very first submission of a public key derived the module, the shared secret key can comprise a pre-shared secret key which can be loaded into the module using a pre-shared secret key code.