SHA-1 Hash
「SHA-1 Hash」はコード、データと QRに使えるブラウザツールです。入力内容と結果は通常この端末内で処理され、登録は必要ありません。
Text is encoded as UTF-8 and processed locally in your browser.
Enter text to begin.
SHA-1 is a one-way digest, not encryption. It cannot be decrypted to recover the original text and is unsuitable for new security designs. Use SHA-256 or SHA-3 for new integrity work, and a password-specific KDF such as Argon2id, scrypt, or PBKDF2 for passwords.
使い方
使い方
- Enter or paste text into the input field.
- Select Generate SHA-1 digest.
- Review or copy the 40-character hexadecimal digest.
A local SHA-1 digest
The page uses the browser’s built-in Web Crypto API to calculate SHA-1 from UTF-8 text. The result is shown as lowercase hexadecimal and is generated entirely on your device.
SHA-1 cannot be decrypted
SHA-1 is a one-way cryptographic digest, not encryption. There is no decryption operation that reliably recovers the original text. Different inputs can also be engineered to share a SHA-1 collision, so do not use it for new security-sensitive designs.
Choose a safer primitive for new work
Use SHA-256 or SHA-3 for new general-purpose integrity or identification tasks. Passwords need a password-specific key derivation function such as Argon2id, scrypt, or PBKDF2 with a unique salt; do not store plain SHA-1 password hashes.
よくある質問
あわせて知りたいこと
Can I decrypt a SHA-1 hash?
No. SHA-1 is a one-way digest, not encryption, so it has no decryption key or reliable reverse operation.
What is SHA-1 useful for?
It can help inspect or compare legacy identifiers and compatibility values. Its collision weaknesses make it unsuitable for new security-sensitive integrity, signing, or password storage.
Is my text uploaded?
No. UTF-8 encoding and hashing run locally in your browser through Web Crypto.
What should I use instead of SHA-1?
Use SHA-256 or SHA-3 for new general-purpose hashing. For passwords, use Argon2id, scrypt, or PBKDF2 with a unique salt.