Hash ジェネレーター
SHA-1、SHA-256、SHA-384、SHA-512 ハッシュを生成
アルゴリズムの詳細
SHA-1: 160ビットハッシュ、レガシー用途のみ（衝突耐性なし）
SHA-256: 256ビットハッシュ、整合性検証やブロックチェーンで広く使用
SHA-384: 384ビットハッシュ、SHA-512 の短縮版
SHA-512: 512ビットハッシュ、SHA-2 系列で最も強力
使い方
テキストを貼り付けまたは入力
テキスト、コード、またはデータを入力エリアに入力します。
オプションを選択
適用する変換やフォーマットを選択します。
結果をコピー
ワンクリックで出力をクリップボードにコピーします。
このツールを使う理由
完全無料
隠れたコストもプレミアムプランもありません — すべての機能が無料です。
インストール不要
すべてブラウザで実行されます。ソフトウェアのダウンロードやインストールは不要です。
プライベート＆安全
データはデバイスの外に出ることはありません。サーバーにアップロードされることはありません。
モバイル対応
完全レスポンシブ対応 — スマートフォン、タブレット、デスクトップで利用できます。
Cryptographic Hash Functions: MD5, SHA-1, SHA-256, and Beyond
Key Takeaways
- Hash functions produce fixed-length fingerprints of data, enabling integrity verification, password storage, and digital signatures.
- MD5 and SHA-1 are considered broken for security purposes — use SHA-256 or SHA-3 for any security-sensitive application.
- All hash computation happens in your browser using the Web Crypto API — your data never leaves your device.
Cryptographic hash functions are one-way transformations that convert any input into a fixed-size output (the hash or digest). They are fundamental to modern computing — from verifying file integrity and storing passwords to powering blockchain technology. Understanding which algorithm to use and when is critical for building secure applications.
SHA-256 produces a 256-bit hash — the probability of two different inputs producing the same hash is roughly 1 in 10^77.
Collision Resistance
Key Concepts
One-Way Property
Hash functions are designed to be computationally infeasible to reverse. Given a hash output, you cannot determine the original input. This property makes them ideal for password storage.
Collision Resistance
A strong hash function makes it extremely difficult to find two different inputs that produce the same hash. MD5 and SHA-1 have known collision attacks, which is why SHA-256 is now the standard.
Avalanche Effect
Changing even a single bit of input produces a completely different hash output. This property ensures that similar inputs cannot be detected by comparing their hashes.
Algorithm Comparison
MD5 (128-bit) is fast but broken. SHA-1 (160-bit) is deprecated. SHA-256 (256-bit) is the current standard. SHA-3 (variable) offers an alternative design. Choose based on your security requirements.
Pro Tips
Never use plain hashes for password storage — use bcrypt, scrypt, or Argon2 which add salt and computational cost.
Use SHA-256 file hashes to verify download integrity — compare with the hash published by the software vendor.
MD5 is still acceptable for non-security uses like cache keys, deduplication checks, and checksums where collision attacks are not a concern.
The Web Crypto API (SubtleCrypto.digest) provides hardware-accelerated hashing in modern browsers — much faster than JavaScript implementations.
All hash generation is performed entirely in your browser using the Web Crypto API. Your input data is never transmitted to any server, making this tool safe for hashing sensitive content.