Infineon Technologies Ag

Giesecke+devrient Mobile Security Gmbh

Giesecke & Devrient Gmbh

Rainer Urian

Thomas Poeppelmann

According to various embodiments, a method for code-based generation of a key pair for asymmetric cryptography is described including generating a private key defining a linear code, determining a parity check or generator matrix for the linear code, blinding a sub-matrix of the parity check or generator matrix, generating a blinded inverse matrix by inverting the blinded sub-matrix or by inverting a quadratic matrix contained in the blinded sub-matrix, de-blinding the blinded inverse matrix to generate an inverse matrix and generating a public key for the private key using the inverse matrix.

Method and device for code-based generation of a key pair for asymmetric cryptography

According to one embodiment, a method performed by a first communication device for generating a symmetric session key for encrypted communication with a second communication device is described comprising generating a blinding value for each of a first and a second private key component, generating a blinded public key from the first private key component, the second private key component, and the blinding values using a public key generation function, transmitting the blinded public key to the second communication device for encryption of a shared secret, receiving the shared secret, generating a session key for encrypted communication with the second communication device from the shared secret, encrypting, using the session key, an information from which the blinding values are derivable and transmitting the encrypted information to the second communication device.

Methods and devices for generating a symmetric session key for encrypted communication

A method is suggested for providing a response, wherein the method comprises: obtaining a challenge from a host, determining the response based on the challenge, determining an auxiliary value based on the response or the challenge, providing the auxiliary value to the host, obtaining a random value from the host, checking the validity of the challenge based on the random value, and providing the response to the host only if the challenge is valid. Also, corresponding methods running on the host and system are provided. Further, corresponding devices, hosts and systems are suggested.

Cryptographic operation

A method is suggested for providing a response, wherein the method comprises: obtaining a challenge from a host, determining the response based on the challenge, determining an auxiliary value based on the response or the challenge, providing the auxiliary value to the host, obtaining a random value from the host, checking the validity of the challenge based on the random value, and providing the response to the host only if the challenge is valid. Also, according methods running on the host and system are provided. Further, corresponding devices, hosts and systems are suggested.

A pseudonymous Diffie-Hellman protocol is provided by means of a combination of the CA protocol with the RI protocol. According to the invention the determining of the pseudonym from the RI protocol and the forming of the secure communication channel from the CA protocol occur substantially in parallel. According to the invention there is likewise employed a group key for the CA part of the protocol according to the invention. Due to the configuration of the protocol according to the invention it is not possible, in contrast to the known protocols, for an attacker who should succeed in establishing the group key of a portable data carrier according to the invention, to generate the pseudonym of another user.

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Augsburg, Germany

Rainer Urian