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Diffstat (limited to '')
-rw-r--r-- | buch/chapters/90-crypto/images/sbox.m | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/buch/chapters/90-crypto/images/sbox.m b/buch/chapters/90-crypto/images/sbox.m new file mode 100644 index 0000000..1f0c2ce --- /dev/null +++ b/buch/chapters/90-crypto/images/sbox.m @@ -0,0 +1,52 @@ +#
+# sbox.m
+#
+# (c) 2021 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule
+#
+A=[
+1,0,0,0,1,1,1,1;
+1,1,0,0,0,1,1,1;
+1,1,1,0,0,0,1,1;
+1,1,1,1,0,0,0,1;
+1,1,1,1,1,0,0,0;
+0,1,1,1,1,1,0,0;
+0,0,1,1,1,1,1,0;
+0,0,0,1,1,1,1,1;
+]
+
+R = zeros(8,16);
+R(:,1:8) = A;
+R(:,9:16) = eye(8);
+
+for k = (1:5)
+ for i=(k+1:8)
+ pivot = R(i,k);
+ R(i,:) = R(i,:) + pivot * R(k,:);
+ end
+ R = mod(R, 2)
+end
+
+P = [
+1,0,0,0,0,0,0,0;
+0,1,0,0,0,0,0,0;
+0,0,1,0,0,0,0,0;
+0,0,0,1,0,0,0,0;
+0,0,0,0,1,0,0,0;
+0,0,0,0,0,0,0,1;
+0,0,0,0,0,1,0,0;
+0,0,0,0,0,0,1,0;
+]
+
+R = P * R
+
+for k = (8:-1:2)
+ for i = (1:k-1)
+ pivot = R(i,k);
+ R(i,:) = R(i,:) + pivot * R(k,:);
+ end
+ R = mod(R, 2)
+end
+
+B = R(:,9:16)
+
+A * B
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