Method for the mutual authentication of entities having previously initiated an online transaction

An authentication method for enabling authentication to be performed between a first portable electronic device of a first entity and a second portable electronic device of a second entity, the first portable electronic device comprising:

• a processor;
• and
• a memory coupled to the processor, the memory storing instructions, which when executed by the processor, cause the processor to perform operations comprising:
• during a first stage in which the first portable electronic device of the first entity communicates with the second portable electronic device of the second entity via a telecommunications network:
• generating, by the first portable electronic device, a first digital cryptographic token;
• and
• transmitting the first digital cryptographic token from the first portable electronic device to the second portable electronic device of the second entity;
• and
• during a second stage, authenticating a first non-authenticated entity as being the second entity as a function of a second digital cryptographic token received from the second portable electronic device and stored in the memory of the first portable electronic device corresponding to the first digital cryptographic token;
• wherein the operations further comprise:
• during the first stage:
• receiving, via the telecommunications network, at the first portable electronic device, a third digital cryptographic token generated by the second portable electronic device;
• and
• during the second stage, transmitting a fourth digital cryptographic token from the first portable electronic device to the second portable electronic device, wherein when the fourth digital cryptographic token is received, a second non-authenticated entity is authenticated as being the first entity as a function of the fourth digital cryptographic token stored in a memory of the second portable electronic device corresponding to the third digital cryptographic token.