A method for the biunique identification of a document (1; 20), which is formed as a security document or a valuable document, wherein the method has the following steps: - providing a document (1; 20), which is produced from one or more materials; - determining a parameter for material comparison for a material property in at least one material section of the document (1; 20); - saving comparison data indicating the parameter for material comparison in a local storage device of the document (1; 20) and/or a central database, wherein the parameter for material comparison is biuniquely assigned to the document (1; 20) and thus forms a unique material signature for the document (1; 20), which differentiates the document (1; 20) from other documents; and - analysing the document (1; 20), wherein here - a material test parameter is determined for the at least one material section and/or a further material section of the document (1; 20), which is different from the at least one material section; - the comparison data are read out from the local storage device of the document (1; 20) and/or the central database and compared with test data, which specify the material test parameter; and - the document (1; 20) is determined to be biuniquely identified on the basis of the material signature if it is established during the comparison of the test data and the comparison data, that the material test parameter corresponds to the parameter for material comparison within predetermined parameter limits. - providing a document (1; 20), which is produced from one or more materials; - determining a parameter for material comparison for a material property in at least one material section of the document (1; 20); - saving comparison data indicating the parameter for material comparison in a local storage device of the document (1; 20) and/or a central database, wherein the parameter for material comparison is biuniquely assigned to the document (1; 20) and thus forms a unique material signature for the document (1; 20), which differentiates the document (1; 20) from other documents; and - analysing the document (1; 20), wherein here - a material test parameter is determined for the at least one material section and/or a further material section of the document (1; 20), which is different from the at least one material section; - the comparison data are read out from the local storage device of the document (1; 20) and/or the central database and compared with test data, which specify the material test parameter; and - the document (1; 20) is determined to be biuniquely identified on the basis of the material signature if it is established during the comparison of the test data and the comparison data, that the material test parameter corresponds to the parameter for material comparison within predetermined parameter limits. - a material test parameter is determined for the at least one material section and/or a further material section of the document (1; 20), which is different from the at least one material section; - the comparison data are read out from the local storage device of the document (1; 20) and/or the central database and compared with test data, which specify the material test parameter; and - the document (1; 20) is determined to be biuniquely identified on the basis of the material signature if it is established during the comparison of the test data and the comparison data, that the material test parameter corresponds to the parameter for material comparison within predetermined parameter limits.