CONNOTECH Experts-conseils Inc.

Synopsis of the Core Frogbit Algorithm

by Thierry Moreau

May 1997

© 1997 CONNOTECH Experts-conseils Inc.


Definitions:
cleartext bits mi
ciphertext bits ei

Encryption equation: ei=k1i XOR mi XOR k2i
Decryption equation: mi=k2i XOR ei XOR k1i

Parameter n, then N=3×2n-2 (preferably n=2, N=10)

Notation:

Unconditional iteration equations: si=k1i XOR mi=k2i XOR ei and r'(i)=r(i) mod n



FGBSYNL.GIF

The matrix P is a fixed table of 2N permutations of N elements, that is 0<=P[j,q]<N, and P[j,q']<>P[j,q''] for q'=q''. A reference matrix P is given for n=2.

The Frogbit uses N independent pseudo-random sources. The bit pair <k1i+1,k2i+1> is given by the d'(i)+1'th source. The state information for pseudo-random sources is part of the global Frogbit state.

 j P[j,0] P[j,1] P[j,2] P[j,3] P[j,4] P[j,5] P[j,6] P[j,7] P[j,8] P[j,9]

 0    5      8      7      9      3      2      4      0      6      1
 1    2      3      7      6      8      1      9      0      5      4
 2    6      0      4      2      3      7      8      1      9      5
 3    6      5      8      4      2      3      0      9      7      1

 4    3      2      0      6      8      1      5      9      7      4
 5    6      2      9      1      5      8      7      3      4      0
 6    4      8      9      7      3      0      1      6      5      2
 7    5      9      3      7      0      4      2      1      6      8

 8    8      0      1      2      6      3      7      4      9      5
 9    9      4      6      5      2      3      0      8      1      7
10    7      6      4      8      1      9      5      2      3      0
11    1      4      8      0      7      2      9      5      3      6

12    7      4      5      0      9      8      3      6      1      2
13    3      9      0      5      6      2      8      4      1      7
14    8      9      1      0      2      7      5      6      4      3
15    9      5      4      1      7      0      3      8      2      6

16    7      3      6      9      5      4      1      2      0      8
17    4      7      9      5      1      6      2      8      0      3
18    2      7      3      8      9      6      4      5      0      1
19    1      6      5      4      0      9      7      3      2      8

security scheme designalternative to PKIpatent publicationsSAKEMscholarly web contentsconsulting services ]
[ CONNOTECH home page: http://www.connotech.com/about us | e-mail to: info@connotech.com ]

CONNOTECH Experts-conseils Inc.
9130 Place de Montgolfier
Montréal, Québec, Canada, H2M 2A1
Tél.: +1-514-385-5691 Fax: +1-514-385-5900