| 摘要 |
A system for encrypting and decrypting digital data wherein the data is divided in packets of N blocks X(1) ... X(N) of 2<m> bits, comprises an encryption device and a decryption device. The encryption device reverses the sequence of the blocks X(1) ... X(N) before a XOR operation and next an encryption operation by means of an encryption algorithm E is carried out on each block of a packet. Thereby the following encrypted blocks Y(1) ... Y(N) are formed: Y(1) = E [X(N) + IV], Y(i) = E [X(N-i+1) + Y(i-1)] for i > 1 and i </= N. The encrypted blocks Y(1) ... Y(N) are transferred by a sender in reversed sequence Y(N) ... Y(1) to a receiver. The decryption device at the receiver obtains the original blocks X(1) ... X(N) by carrying out a decryption operation by means of a decryption algorithm D and next a XOR operation on each block Y(N) ... Y(1) received. Thereby the original blocks are obtained as follows: X(i) = D [Y(N-i+1)] + Y(N-i) for i = 1, 2, ..., N-1; X(N) = D [Y(1)] + IV. |
| 申请人 |
IRDETO B.V.;KUEHN, GIDEON, JACOBUS;DAVIES, DONALD, WATTS;RIX, SIMON, PAUL, ASHLEY |
发明人 |
KUEHN, GIDEON, JACOBUS;DAVIES, DONALD, WATTS;RIX, SIMON, PAUL, ASHLEY |
