Signal と WhatsApp: 実際にチャットをプライベートに保つメッセンジャーはどれですか?
2026 年 6 月 24 日 · 2 分で読みました · コメント
どちらのアプリもエンドツーエンドの暗号化を使用していると述べています。しかし、暗号化は話の一部にすぎません。実際にそれらを区別するものは次のとおりです。
エンドツーエンド暗号化の実際の意味
- End-to-end encryption means only you and the person you're messaging can read the contents of your messages. Not the app company, not your mobile carrier, not the government — unless they get into your actual phone.
- Both Signal and WhatsApp use end-to-end encryption for message content. On this point, they are equal. The difference is everything else.
メタデータの問題
- Even if WhatsApp can't read your messages, it can — and does — collect metadata: who you talk to, how often, at what times, your location, your device, your contacts list.
- Meta (WhatsApp's parent company) uses this data to build advertising profiles and shares it across Instagram and Facebook.
- Signal collects almost none of this. The only data Signal holds about you is your phone number and the date you last connected.
オープンソースとクローズドソース
- Signal's code is open source — anyone can read it, audit it, and verify it does what it claims. Security researchers around the world have done exactly this.
- WhatsApp's code is closed. You have to take Meta's word for it that the encryption is correctly implemented and that no backdoors exist. Given Meta's track record with user data, that's a lot of trust.
Signal の実質的な欠点
- The only real drawback: your contacts need to have Signal too. You can't send a Signal message to a WhatsApp user.
- Signal has grown significantly — it now has over 100 million users. Many people already have it.
- The practical approach: keep WhatsApp for group chats with family who won't switch, move sensitive conversations to Signal.
Advantage: シグナル — プライバシーが重要な場合は、大差で。
