Method for designing a circuit suitable for generating random bits, wherein - the circuit has a number m of mapping devices (K1, K2,... Kj,... Ki,... Km); - each of the mapping devices (K1, K2,... Kj,... Ki,... Km) is supplied a number n of input bits, where n is a value greater than 1; - each of the mapping devices (K1, K2,... Kj,... Ki,... Km) uses a respective function (f 1, f 2,... f j,... f i,... f m) to carry out a bijective mapping of the n input bits to n output bits, having the following steps: (a) selection of a j-th mapping device (K j) from the first mapping device (K 1) to m-th mapping device (K m) and prescribing of a j-th specific function (g j) from a set of bijective mappings as the j-th function (f j), wherein - a j-th concatenation (f j ') of the j functions (f 1,... f j) carries out a j-th fixed-point-free mapping when the j-th specific function (g j) is prescribed as the j-th function (f j); - the j-th concatenation applies the j functions in an ascending order starting with the first function (f 1); (b) selection of at least one i-th mapping device (K i) from the first mapping device (K 1) to m-th mapping device (K m), where i is not equal to j, and prescribing of an i-th specific function (g i) from a set of bijective mappings as the i-th function (f i), wherein - an i-th concatenation (f i ') of the i functions (f 1,... f i) carries out an i-th fixed-point-free mapping when the i-th specific function (g i) is prescribed as the i-th function (f i); - the i-th concatenation applies the i functions in an ascending order starting with the first function (f 1). - the circuit has a number m of mapping devices (K1, K2,... Kj,... Ki,... Km); - each of the mapping devices (K1, K2,... Kj,... Ki,... Km) is supplied a number n of input bits, where n is a value greater than 1; - each of the mapping devices (K1, K2,... Kj,... Ki,... Km) uses a respective function (f 1, f 2,... f j,... f i,... f m) to carry out a bijective mapping of the n input bits to n output bits, having the following steps: (a) selection of a j-th mapping device (K j) from the first mapping device (K 1) to m-th mapping device (K m) and prescribing of a j-th specific function (g j) from a set of bijective mappings as the j-th function (f j), wherein - a j-th concatenation (f j ') of the j functions (f 1,... f j) carries out a j-th fixed-point-free mapping when the j-th specific function (g j) is prescribed as the j-th function (f j); - the j-th concatenation applies the j functions in an ascending order starting with the first function (f 1); (b) selection of at least one i-th mapping device (K i) from the first mapping device (K 1) to m-th mapping device (K m), where i is not equal to j, and prescribing of an i-th specific function (g i) from a set of bijective mappings as the i-th function (f i), wherein - an i-th concatenation (f i ') of the i functions (f 1,... f i) carries out an i-th fixed-point-free mapping when the i-th specific function (g i) is prescribed as the i-th function (f i); - the i-th concatenation applies the i functions in an ascending order starting with the first function (f 1). (a) selection of a j-th mapping device (K j) from the first mapping device (K 1) to m-th mapping device (K m) and prescribing of a j-th specific function (g j) from a set of bijective mappings as the j-th function (f j), wherein - a j-th concatenation (f j ') of the j functions (f 1,... f j) carries out a j-th fixed-point-free mapping when the j-th specific function (g j) is prescribed as the j-th function (f j); - the j-th concatenation applies the j functions in an ascending order starting with the first function (f 1); - a j-th concatenation (f j ') of the j functions (f 1,... f j) carries out a j-th fixed-point-free mapping when the j-th specific function (g j) is prescribed as the j-th function (f j); - the j-th concatenation applies the j functions in an ascending order starting with the first function (f 1); (b) selection of at least one i-th mapping device (K i) from the first mapping device (K 1) to m-th mapping device (K m), where i is not equal to j, and prescribing of an i-th specific function (g i) from a set of bijective mappings as the i-th function (f i), wherein - an i-th concatenation (f i ') of the i functions (f 1,... f i) carries out an i-th fixed-point-free mapping when the i-th specific function (g i) is prescribed as the i-th function (f i); - the i-th concatenation applies the i functions in an ascending order starting with the first function (f 1). - an i-th concatenation (f i ') of the i functions (f 1,... f i) carries out an i-th fixed-point-free mapping when the i-th specific function (g i) is prescribed as the i-th function (f i); - the i-th concatenation applies the i functions in an ascending order starting with the first function (f 1).