Secure authenticated distance measurement

A system for controlling the transmission of protected content from a content provider to a requesting device, the content provider comprising:

• means for receiving a certificate of the requesting device, the certificate providing information for validating the requesting device as being compliant with a set of compliancy rules;
• means for validating that the requesting device is compliant with the set of compliancy rules using said information contained in said certificate;
• means for transmitting a first signal to the requesting device at a first time when said requesting device is validated as being compliant with the set of compliancy rules;
• means for receiving a second signal at a second time from the requesting device;
• means for providing the protected content to the requesting device after determining the second signal depends on a secret known to the content provider, and
• a time difference between the first time and the second time is less than a predetermined time.

A first device in communication with a second device, the first device comprising:

• a memory;
• a processor in communication with the memory, the processor arranged to execute software stored on the first device, the software configured to:
• receive from the second device a request for a protected content and a certificate providing information associated with the second device;
• determine whether the second device is suitable for receiving said protected content, wherein determining suitability of said second device is based on said information provided in said certificate;
• provide a first signal to said second device when said second device is determined to be suitable for receiving said protected content;
• receive from said second device a second signal;
• determine whether said second signal is representative of said first signal modified according to a secret known by said first device and said second device;
• determine whether a time difference between a time of providing the first signal and receiving the second signal is less than a predetermined time;
• and
• initiate transmission of said protected content to said second device when at least said second signal is representative of said first signal modified according to a secret known by said first device and said second device and said time difference is less than the predetermined time.

A method of a first device controlling delivery of protected content to a second device, the method comprising:

• receiving a certificate of the second device, the certificate providing information regarding the second device;
• determining whether the second device is compliant with a set of compliance rules utilizing said information provided in said certificate;
• providing a first signal to the second device depending when the second device is determined to be compliant with the set of compliance rules;
• receiving a second signal from the second device after providing the first signal;
• determining whether the second signal is derived from a secret known by the first device;
• determining whether a time difference between providing the first signal and receiving the second signal is less than a predetermined time;
• and
• allowing the protected content to be provided to the second device when at least the second signal is determined to be derived from the secret and the time difference is less than the predetermined time.

A first device for controlling delivery of protected content to a second device, the first device comprising:

• a memory;
• a processor, the processor arranged to:
• receive a certificate from the second device prior to sending a first signal;
• determine from the certificate if the second device is compliant;
• provide a secret to the second device via encryption by a public key of a private/public key-pair of the second device, if the second device is compliant, said secret comprising a random number;
• provide the first signal to the second device;
• receive a second signal from the second device after providing the first signal;
• determine if the second signal is derived from the secret by determining whether the second signal is the first signal modified based on the secret;
• determine whether a time difference between providing the first signal and receiving the second signal is less than a predetermined time;
• and
• allow the protected content to be provided to the second device at least when the second signal is determined to be derived from the secret and the time difference is less than the predetermined time.

A method of a first device controlling delivery of protected content to a second device, the method comprising:

• receiving a certificate from the second device prior to sending a first signal;
• determining from the certificate if the second device is compliant;
• providing a secret to the second device via encryption by a public key of a private/public key-pair of the second device, if the second device is compliant, said secret comprising a random number;
• providing the first signal to the second device;
• receiving a second signal from the second device after providing the first signal;
• determining if the second signal is derived from the secret by determining whether the second signal is the first signal modified based on the secret;
• determining whether a time difference between providing the first signal and receiving the second signal is less than a predetermined time;
• and
• allowing the protected content to be provided to the second device at least when the second signal is determined to be derived from the secret and the time difference is less than the predetermined time.