Method of providing an authenticable time-and-location indication

A radio-navigation signal receiver comprising a memory and a processor coupled to perform:

• a) receiving radio-navigation signals broadcast from a plurality of radio-navigation signal sources, at least some of said radio-navigation signals containing one or more cryptographic tokens per signal source protected by encryption, said cryptographic tokens being updated from time to time;
• b) retrieving said cryptographic tokens from said radio-navigation signals containing them, by decryption;
• c) determining positioning data based on said radio-navigation signals received, said positioning data, including geographical position and time of said radio-navigation signal receiver;
• d) generating a digital authentication code using a cryptographic function taking as inputs at least said positioning data and said retrieved cryptographic tokens;
• e) producing a data package including a first and a second part, said first part containing said positioning data and a receiver public identifier and said second part containing said digital authentication code;
• and
• f) providing further data to protect user identification data, signal-in-space integrity data, a receiver software fingerprint, further positioning data, digital signature identifying the user and/or one or more digital documents, wherein said digital authentication code is generated using said cryptographic function taking as an input also said further data to protect.

A method of checking authenticity of a data package, said method comprising:

• receiving a data package having allegedly been produced according to a method of providing an authenticable time-and-location indication using a radio-navigation signal receiver, said data package including a first part containing positioning data and a second part containing a digital authentication code, said positioning data including alleged geographical position and time, said method of providing an authenticable time-and-location indication using a radio-navigation signal receiver comprising the following steps:
• a) receiving radio-navigation signals broadcast from a plurality of radio-navigation signal sources, at least some of said radio-navigation signals containing one or more cryptographic tokens per signal source protected by encryption, said cryptographic tokens being updated from time to time;
• b) retrieving said cryptographic tokens from said radio-navigation signals containing them, by decryption;
• c) determining positioning data based on said radio-navigation signals received, said positioning data, including geographical position and time of said radio-navigation signal receiver;
• d) generating a digital authentication code using a cryptographic function taking as inputs at least said positioning data and said retrieved cryptographic tokens;
• e) producing said data package including said first and said second part, said first part containing said positioning data and a receiver public identifier and said second part containing said digital authentication code;
• and
• f) providing further data to protect user identification data, signal-in-space integrity data, a receiver software fingerprint, further positioning data, digital signature identifying the user and/or one or more digital documents, wherein said digital authentication code is generated using said cryptographic function taking as an input also said further data to protect;
• retrieving one or more cryptographic tokens that said radio-navigation signal receiver would have received had said radio-navigation signal receiver actually been at said geographical position at said time;
• checking whether said positioning data and said digital authentication code are consistent with each other;
• authenticating said data package when said positioning data and said digital authentication code are consistent with each other, or rejecting said data package as invalid when said positioning data and said digital authentication code are not consistent with each other.