よくある誤解：Base64は安全か？
A widespread misunderstanding among web developers and system administrators is assuming that Base64-encoded text is secure because it looks like a scrambled, unintelligible random string of characters.
⚠️ Security Warning: Base64 encoding provides ZERO confidentiality or security. Anyone who intercepts a Base64-encoded string can instantly convert it back to plaintext without needing a secret key, password, or certificate.
比較：エンコード vs 暗号化 vs ハッシュ化
| Property | Encoding (Base64) | Encryption (AES / RSA) | Hashing (SHA-256) |
|---|---|---|---|
| Primary Purpose | Data format compatibility across text systems | Data confidentiality & privacy protection | Data integrity & password verification |
| Secret Key Required? | No Key | Requires Key / Password | No Key (One-way) |
| Reversible? | 100% Reversible by Anyone | Reversible ONLY with Secret Key | Irreversible (One-way) |
| Standard Example | RFC 4648 Base64 | AES-256-GCM, RSA-4096 | SHA-256, bcrypt, Argon2 |
オンラインツールを試す
文字列、ファイル、画像をエンコードまたはデコードする必要がありますか？ 100%クライアントサイドツールをご利用ください：