# Determining number of required plaintext pairs for differential cryptanalysis

When carrying differential analysis of a SPN network, how can one determine the number of required plaintext for the attack to be successful with high probability?

• You might want first to compute the probability of your trails and select the one with the highest chances.
– Biv
Apr 6, 2017 at 16:11
• @Biv I've already done that. Just not sure how to proceed from this point. Apr 6, 2017 at 16:12
• let us assume that you have a probability $1/2^p$, then you will need at least $2^p$ pair to exhibit this characteristic once (in average). By multiplying this number by... 1000 you should be able to have the number of pair that you need.
– Biv
Apr 6, 2017 at 16:24
• For DES, they need $2^{20} \approx 1000000$ pairs while the probability of the characteristic is $1/55000$.
– Biv
Apr 6, 2017 at 16:27
• @Biv I am facing the same question as SpiderRico. Hope I can get an answer here: Let us assume I have a trail with probability 0.0264. This is as fraction 7/1024. 1024 = 2^10 => I need at least 1024 Pairs, right? Do you may be have some literature about that? May be a paper? I need something to read about that, but did not find anything except this post here. Apr 26, 2019 at 17:12