Device and method for processing digital values in particular in non-adjacent form

A chip card having an integral device for processing numerical values, that comprises:

• first storage means having at least one correspondence table that defines correspondences between first sets of at least one digit, expressed according to a signed code where each digit has a value of 0, 1 or −1, and second sets of at least one digit, expressed according to a simple form where each digit has a value of 0 or 1;
• and
• conversion means including:
• means for inputting values to be processed in the form of a sequence of digits,
• decomposition means for decomposing the sequence of digits into sets of digits appearing in said correspondence table,
• extraction means for extracting from the correspondence table, for each set of digits resulting from the decomposition, the corresponding set of digits given by said correspondence table,
• compilation means for compiling a sequence of digits from the sets extracted by the extraction means, and
• means for outputting the sequence compiled by the compilation means
• wherein the conversion means generates a compact coded outputted sequence of digits from the inputted sequence of digits expressed according to the signed code, or the conversion means generates a non-compact coded outputted sequence of digits from the inputted sequence of digits expressed according to the simple form, the compact coded sequence of digits requiring less storage space than the non-compact coded sequence of digits.

A method for processing numerical values, comprising the steps of:

• establishing at least one correspondence table that defines correspondences between first sets of at least one digit, expressed according to a signed binary code where each digit has a value of 0, 1 or −1, and second sets of at least one digit, expressed according to a simple form where each digit has a value of 0 or 1;
• and
• carrying out a conversion by the steps of:
• receiving input values to be processed in the form of a sequence of digits,
• decomposing said sequence of digits into sets of digits appearing in said correspondence table,
• extracting from said correspondence table, for each set of digits resulting from the decomposition, a set of corresponding digits given by said correspondence table,
• compiling a sequence of digits from the sets thus extracted, and
• outputting the compiled sequence, wherein the outputting step comprises outputting a compact coded compiled sequence of digits from the inputted sequence of digits expressed according to the signed code, or outputting a non-compact coded compiled sequence of digits from the inputted sequence of digits expressed according to the simple form, the compact coded sequence of digits requiring less storage space than the non-compact coded sequence of digits.