Diffusion oriented method and apparatus for stream cryptography

A stream cryptographic method comprising:

• a communications channel between a first computer and a second computer;
• a diffusion-area A, wherein A contains an initial value A0 and further, is a d1×d2× . . . ×dm binary matrix with a combination of positions labeled sequentially from 1 to n, accordingly, the bit values from a1 to an;
• a function-table Ft1 applied to A, notated AFt1 in abbreviation, wherein Ft1 has d1×d2× . . . ×dm layer, and every layer is a d1×d2× . . . ×dm, binary matrix;
• a diffusion-medium S, wherein S is a m-dimensional binary matrix which includes an anchor-position {dot over (S)};
• a medium-constant BFt1, wherein BFt1=BF(p1, p2t1pk) and B is a D1×d2=. . . =dm zero matrix;
• and further, comprising steps of;
• (I) generating, by the first and second computers, an assigned bit for stream encryption/decryption by;
• (a) setting t2=1, At1×(t2−1)=A0;
• (b) obtaining the medium-constant BFt1, further comprising steps of:
• (i) setting t=1;
• (ii) setting s=1;
• (iii) performing B with a diffusion function F(ps), namely BF(ps), wherein S overlaps B by {dot over (S)} anchoring to the position ps transforming into m-dimension coordinates (i1, i2, . . . , im), then BF(ps)=B⊕Bd1i⊕Bd2i⊕. . . ⊕ Bdmi⊕S, 1≦ps≦n;
• (iv) if s=k, then going to next step;
• otherwise, s=s+1, going back to Step (iii)
• (v) if t≢t1, then t=t+1, going back to Step (ii),
• (c) obtaining a new value At1×t2, wherein At1×t2=At1×(t2−1)Ft1⊕BFt1, wherein At1×(t2−1)Ft1 obtains new ai, 1≦n, by XORing with said layers having value 1 at position i, wherein the ith layer represent ai;
• (d) outputting an assigned bit of At1×t2;
• (II) encrypting, by the first computer, a bit of a plaintext stream in sequence, wherein in the bit of the plaintext stream XORs with the assigned bit of At1×t2;
• (III) decrypting, by the second computer, a bit of the ciphertext stream in sequence, received from the first computer, wherein the bit of the ciphertext steam XORs with the assigned bit of At1×t2;
• (IV) going to Step (c), and further, ;
• letting t2=2+1.

A stream cryptographic apparatus comprising of:

• a first register R1 provided for storing an input value At1×(t2−1);
• a diffuser DF provided for receiving At1×(t2−1) from the first register R1, further,
• recombining At1×(t2−1) with a function-table Ft1 and transmitting an output value At1×t2=At1×(t2−1)Ft1;
• a second register R2 provided for receiving and buffering At1×t2 from the diffuser DF, then, feeding back said At1×t2 to the first register R1;
• a multiplexer MUX provided for receiving At1×t2 from the second register R2, further, selecting an assigned bit of At1×t2 and transmitting the assigned bit;
• a third register R3 provided for storing a plaintext/ciphertext stream in sequence, the third register R3 input marked IN, and transmitting a bit each time;
• an XOR gate provided for receiving said assigned bit from the multiplexer MUX as a first operand, said bit from the third register R3 as a second operand, then, performing an exclusive or operation and transmitting an output bit;
• the output marked OUT.