Crypto Algorithm Evaluation - Public key algorithm

  I                       V
  |                       |
  |              +--------+ P: Permute bits
+---+            |        | output[p]=input[(p*(N-1)/2)mod N]
| P |  +---+-----------+  |
+---+  |   |           |  | R:Rotation matrix
  |    |   |           |  | First row filled with input
  +----| K |     R     |  | Each row is the preceding 
  k1   |   |           |  | rotated right one position
       |   |           |  | Output: xor of rows where
       +---+-----------+  | bit in K is 1 (lsb on top)
                 |        |
  +--------------+        | Key agreement:
  |                       | Va=X(I,a),Vb=X(I,b)
  |                       | r=X(Va,X(b,I))
  |              +--------+ r=X(Vb,X(a,I))
+---+            |        | Secret values are a, b
| P |  +---+-----------+  | Transmitted values are Va, Vb
+---+  |   |           |  |
  |    |   |           |  | Hash signature:
  +----| K |     R     |  | s=X(H,J), H=hash to sign
  k2   |   |           |  | Check:
       |   |           |  | X(X(I,a),s)=X(X(I,H),X(a,J))
       +---+-----------+  | Secret value is J
                 |        | Public values are X(a,J),x(I,a)
  +--------------+        |
  |                       | N safe prime, n=N/log2(N)
  .                       . each line is N bits wide
  .                       .
  .                       .
  |                       |
  |              +--------+
+---+            |        
| P |  +---+-----------+  
+---+  |   |           |  
  |    |   |           |  
  +----| K |     R     |  
  kn   |   |           |  
       |   |           |  
       +---+-----------+  
                 |        
                 |
                 C
X(I,V)=C


(c) Daniel Nager - daniel.nager at gmail.com

N number of bits

Y:
input a,b
output r

	r=0 ; all bits 0
	for i in 0..N-1 do
		if bit(a,(i*(N-1)/2)mod N)=1 then
			r=xor(r,b)
		endif
		b=ror(b) ; bitwise rotate right
	endfor
end Y

X:
input b, a
output r

	r=b
	for i in 0..n-1 do
		r=Y(r,a)
	endfor

end X

a and b are N bit arrays, n is the number of rounds

The following holds:
X(X(I,a),X(b,I))=X(X(I,b),X(a,I))
where I is an arbitrary N-bit array and a,b the secret values
of each part.

In a diffie-hellman like key agreement Va=X(I,a) and Vb=X(I,b) is
sent in each direction and the secret key is calculated 
k=X(Va,X(b,I))=X(Vb,X(a,I))