diff --git a/cw/cw.tex b/cw/cw.tex index 2fd1f92..36e44c2 100644 --- a/cw/cw.tex +++ b/cw/cw.tex @@ -147,14 +147,14 @@ \subsection*{4.3} Our random value is $R = u-bit long digit$ which means that it has $2^u$ possible values. And since we know that $q$ balls into $p$ holes a colision is bound to happend at the probability of $\frac{q^2}{2p}$ we can calculate: - $$\frac{q^2}{2(2^u)}\gt\frac{1}{2}\iff q\gt 2^{\frac{u}{2}}$$ + $$\frac{q^2}{2(2^u)}>\frac{1}{2}\iff q> 2^{\frac{u}{2}}$$ \subsection*{4.4} The size of TripleDES is 64 bit long which makes $u=64/2=32$ making the q - $q\gt 2^\frac{32}{2}\iff q \gt 65536$ + $q> 2^\frac{32}{2}\iff q > 65536$ \subsection*{4.5} The size of AES is 128 bit long which makes $u=128/2=64$ making the q - $q\gt 2^\frac{64}{2}\iff q \gt 4294967296$ + $q>t 2^\frac{64}{2}\iff q > 4294967296$ \subsection*{4.6} Since in in both 4.4 and 4.5 the value of $q$ is not large enough the scheme is not CPA secure