Coding method and system with enhanced security

A method of producing a code with enhanced acquisition security, comprising the steps of:

• generating a plurality of linear component codes, C.sub.1, C.sub.2, . . . C.sub.n ;
• combining said linear component codes to form a linear first composite code in accordance with a first composition rule of such a character that said first composite code does not correlate with said component codes;
• nonlinearizing said first composite code to form a nonlinear second composite code;
• time delaying said component codes, C.sub.1, C.sub.2, . . . C.sub.n-1 ;
• and
• combining said delayed codes, C.sub.1, C.sub.2, . . . C.sub.n-1, with said nonlinear second composite code to form a nonlinear acquisition composite code in accordance with a second composition rule of such a character that at least one of said delayed codes correlates with said acquisition composite code.

A method of producing a code with enhanced acquisition security, comprising the steps of:

• generating a plurality of linear component codes, C.sub.1, C.sub.2, . . . C.sub.n ;
• combining said linear component codes in accordance with a modulo-2 addition rule to form a linear first composite code;
• nonlinearizing said first composite code by applying the same to an encrypter operating in a decrypt mode to form a nonlinear second composite code;
• time delaying said component codes, C.sub.1, C.sub.2, . . . C.sub.n-1 ;
• and
• combining said time delayed codes, C.sub.1, C.sub.2, . . . C.sub.n-1, with said nonlinear second composite code in accordance with a Boolean majority voting rule to form a nonlinear acquisition composite code.

A system for producing a code with enhanced acquisition security, comprising:

• means for generating a plurality of linear component codes, C.sub.1, C.sub.2, . . . C.sub.n ;
• means for combining said linear component codes to form a linear first composite code in accordance with a first composition rule of such a character that said first composite code does not correlate with said component codes;
• means for nonlinearizing said first composite code to form a nonlinear second composite code;
• and
• means for combining said linear component codes, C.sub.1, C.sub.2, . . . C.sub.n-1, with said nonlinear second composite code to form a nonlinear acquisition composite code in accordance with a second composite rule of such a character that at least one of said component codes correlates with said acquisition composite code.

A system for producing a code with enhanced acquisition security, comprising:

• means for generating a plurality of linear component codes, C.sub.1, C.sub.2, . . . C.sub.n ;
• means for combining said linear component codes to form a linear first composite code in accordance with a first composition rule of such a character that said first composite code does not correlate with said component codes;
• means for nonlinearizing said first composite code to form a nonlinear second composite code;
• means for time delaying said component codes, C.sub.1, C.sub.2, . . . C.sub.n-1 ;
• and
• means for combining said delayed codes, C.sub.1, C.sub.2, . . . C.sub.n-1, with said nonlinear second composite code to form a nonlinear acquisition composite code in accordance with a second composition rule of such a character that at least one of said delayed codes correlates with said acquisition composite code.

A coding method for communication between a transmitter and a receiver with enhanced security, comprising the steps of:

• (I) at the transmitter,
• (a) generating a plurality of linear acquisition component codes, C.sub.1, C.sub.2, . . . C.sub.n,
• (b) combining said acquisition component codes to form a linear first composite code in accordance with a first composition rule of such a character that said first composite code does not correlate with said component codes,
• (c) nonlinearizing said first composite code to form a nonlinear second composite code,
• (d) combining said linear component codes, C.sub.1, C.sub.2, . . . C.sub.n-1, with said nonlinear second composite code to form a nonlinear acquisition composite code in accordance with a second composition rule of such a character that at least one of said component codes correlates with said acquisition composite code, and
• (e) transmitting said nonlinear acquisition composite code;
• and
• (II) at the receiver,
• (a) receiving said nonlinear acquisition composite code,
• (b) generating a plurality of linear reference component codes, R.sub.1, R.sub.2, . . . R.sub.n, that correlate respectively with said linear acquisition component codes, C.sub.1, C.sub.2, . . . C.sub.n,
• (c) combining said reference component codes to form a linear third composite code in accordance with said first composition rule,
• (d) nonlinearizing said third composite code in a manner identical to that of said (I,c) nonlinearizing step to form a nonlinear fourth composite code,
• (e) correlating said reference component codes, R.sub.1, R.sub.2, . . . R.sub.n-1, with said nonlinear acquisition composite code by shifting the phases of said reference component codes, R.sub.1, R.sub.2, . . . R.sub.n-1, and
• (f) correlating said nonlinear fourth composite code with said nonlinear acquisition composite code by shifting the phase of the remaining reference component code, R.sub.n.