A method for strong authentication of an individual implemented by a server and a client device that are connected; the client device having a candidate biometric data of the individual and an image acquired from an identity document representing at least one photograph of said individual and one optical reading data visible on said identity document, and the server having a cryptographic footprint of a first concatenation of said optical reading data of said identity document and of a first random data, so-called cryptographic footprint; wherein the method is characterized in that it comprises the implementation by data processing means (21, 31) of the server and/or of the client device of steps of; (b) Extraction, by analysis of said image acquired from said identity document, of: ∘ candidate information representative of the appearance of said photograph as depicted in the acquired image; ∘ said optical reading data as depicted in the acquired image; (c) Calculation of a first data decoded by application of a decoding process to said candidate information representative of the appearance of said photograph and to a first encoded data, such that said first decoded data matches the first random data if said candidate information representative of the appearance of said photograph coincides a reference information representative of the appearance of said photograph; (d) Verification that: - a cryptographic footprint of a first concatenation of the extracted optical reading data and of the decoded data coincides with said first cryptographic footprint in the possession of the server; and - a reference biometric data and the candidate biometric data of the individual match. the client device having a candidate biometric data of the individual and an image acquired from an identity document representing at least one photograph of said individual and one optical reading data visible on said identity document, and the server having a cryptographic footprint of a first concatenation of said optical reading data of said identity document and of a first random data, so-called cryptographic footprint; wherein the method is characterized in that it comprises the implementation by data processing means (21, 31) of the server and/or of the client device of steps of; (b) Extraction, by analysis of said image acquired from said identity document, of: ∘ candidate information representative of the appearance of said photograph as depicted in the acquired image; ∘ said optical reading data as depicted in the acquired image; ∘ candidate information representative of the appearance of said photograph as depicted in the acquired image; ∘ said optical reading data as depicted in the acquired image; (c) Calculation of a first data decoded by application of a decoding process to said candidate information representative of the appearance of said photograph and to a first encoded data, such that said first decoded data matches the first random data if said candidate information representative of the appearance of said photograph coincides a reference information representative of the appearance of said photograph; (d) Verification that: - a cryptographic footprint of a first concatenation of the extracted optical reading data and of the decoded data coincides with said first cryptographic footprint in the possession of the server; and - a reference biometric data and the candidate biometric data of the individual match. - a cryptographic footprint of a first concatenation of the extracted optical reading data and of the decoded data coincides with said first cryptographic footprint in the possession of the server; and - a reference biometric data and the candidate biometric data of the individual match.