Method for establishing a secured communication without preliminary information share
View Patent ↗The invention relates to a method for generating a session key between two communicating electronic devices not requiring any prerecorded information in one of the two devices and enabling the authentication of one of said devices. The method uses a close collaboration between a symmetrical algorithm and an asymmetrical algorithm.
1. A method for establishing secured communication between a first communicating electronic device and a second communicating electronic device that is a reader, each having at least one random number generator, a symmetrical encryption algorithm an asymmetrical encryption algorithm and a mathematical function, said first communicating electronic device being associated with a cryptographic certificate, a public key and a private key, the method comprising at least the stages of:
providing an engagement, during which said first communicating electronic device generates a first random number and informs said reader of the identity of said first communicating electronic device,
providing a challenge, during which said reader obtains the public key and subsequently generates a second random number, encrypts it using said asymmetrical encryption algorithm and the public key and transmits it to said first communicating electronic device,
providing a response, during which said first communicating electronic device decrypts the second random number with said asymmetrical encryption algorithm and said private key, encrypts said first random number with said symmetrical encryption algorithm and the second random number by way of a key, sends this encrypted data to said reader and generates a session key by applying said mathematical function to said first and second random numbers, and
providing verification, during which said reader decrypts said first random number received with the symmetrical encryption algorithm and the second random number by way of a key and subsequently generates a session key by applying said mathematical function to said first and second random numbers.
2. The method according to claim 1 , wherein at a previous stage, said public key is recorded in said reader.
3. The method according to claim 1 , wherein said reader obtains said public key from a third communicating electronic device.
4. The method according to claim 1 , further comprising, on the part of the reader, a stage involving verification of the identity of said first communicating electronic device during which said reader obtains said cryptographic certificate and checks its validity with said public key by means of the asymmetrical encryption algorithm.
5. The method according to claim 4 , wherein at a previous stage, said cryptographic certificate is recorded in said reader.
6. The method according to claim 4 , wherein said reader obtains said cryptographic certificate from said first communicating electronic device during the engagement.
7. The method according to claim 4 , wherein said reader obtains said cryptographic certificate from a third communicating electronic device.
8. The method according to claim 1 , wherein said asymmetrical encryption algorithm with a public key is a Rivest Shamir Adleman algorithm.
9. The method according to claim 1 , wherein said asymmetrical encryption algorithm with a public key is the “RSA for paranoid” algorithm.
10. The method according to claim 1 , wherein said asymmetrical encryption algorithm with a public key is based on the elliptical curves.
11. The method according to claim 1 , wherein said symmetrical encryption algorithm is a Data Encryption Standard (DES) algorithm.
12. The method according to claim 1 , wherein said symmetrical encryption algorithm is the triple DES algorithm.
13. The method according to claim 1 , wherein said symmetrical encryption algorithm is an Advanced Encryption Standard (AES) algorithm.