Cryptography Reference
In-Depth Information
Figure 6.9 - Second iteration of the line - column decoding process.
II. There must be at least 2 wrong letters.
III. CANES is correct
IV. Replacing the P with a G, we get AGONS (conflicts)
V. We can replace the P with an L, getting LENTO (slow).
After this step, there is still one wrong line.
It is possible to correct it by
decoding the columns again (Figure 6.9(b)).
1. VOCAL is a synonym of oral.
2. IMAGE is also a kind of representation.
3. TENON is correct.
4. AGENT is correct.
5. LASSO is correct.
After this final decoding step, the wrong word on line II is identified: it is
OMEGA, another Greek letter.
A certain number of remarks can be made after this experience of decoding
a parallel concatenated code.
•
To arrive at the right result, two iterations of the line and column decoding
were necessary. It would have been a pity to stop after just one iteration.
But that is what we do in the case of a classical concatenated code such
as that of Figure 6.1.
