悪魔の証明 — The Devil’s Proof
2026-10-26
Recently, some customers asked us about a PHP vulnerability that was being discussed in Japan.
悪魔の証明 — The Devil’s Proof
Recently, some customers asked us about a PHP vulnerability that was being discussed in Japan.
“Did you fix it?”
We answered, “Yes. Our servers have been updated and the vulnerability has been addressed.”
Then came the next question:
“Can you prove that the problem no longer exists?”
This is what we call 悪魔の証明 (Akuma no Shōmei) — “the Devil’s Proof.”
The expression comes from an old legal concept rooted in Roman law, later known in Latin as probatio diabolica. It describes the extreme difficulty of proving something for which evidence may not exist—particularly proving a negative.
For example, I can show you which PHP version is running. I can show you that a security patch was installed. I can show you when the server was updated and how it was tested.
But if you ask:
“Can you prove that this problem can never happen?”
No.
To prove that absolutely, I would have to prove that the problem cannot occur under any possible condition, now or in the future.
That is the Devil’s Proof.
In technology, responsible security does not mean promising that nothing can ever go wrong. It means identifying known risks, fixing them, documenting what was done, testing the result, and continuing to maintain the system.
We can prove what we did.
We cannot prove that something will never happen.
We cannot prove that something will never happen.
That distinction is important—in law, in technology, and in business.
Disclaimer: I use AI as a tool to help create images and proofread my writing. However, the ideas, opinions, experiences, and messages in my posts are my own. AI does not generate my posts for me. It simply helps me present my own words and ideas more clearly.
Kenichi Uchikura
Founder & CEO
Pacific Software Publishing, Inc. (PSPINC)
Uchikura & Co., LLC.
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ABOUT THIS BLOG
I was born and raised in Japan and have spent most of my adult life in the United States. Through this blog, I share Japanese culture, language, expressions, and wisdom. My goal is not to say one culture is better, but to explore different perspectives and what we can learn from them.
Your comments are always welcome.
..-･**･-....-･･-..__..-･･-....-･**･-..
Kenichi Uchikura
Founder & CEO
Pacific Software Publishing, Inc. (PSPINC)
Uchikura & Co., LLC.
..-･**･-....-･･-..__..-･･-....-･**･-..
ABOUT THIS BLOG
I was born and raised in Japan and have spent most of my adult life in the United States. Through this blog, I share Japanese culture, language, expressions, and wisdom. My goal is not to say one culture is better, but to explore different perspectives and what we can learn from them.
Your comments are always welcome.
..-･**･-....-･･-..__..-･･-....-･**･-..