D2D Utilities
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JWT Inspector & Verifier

SubtleCrypto Verifier

Inspect JSON Web Tokens, evaluate claims, track expiration validity, and verify HMAC signatures locally via Web Crypto Subtle without transmitting credentials.

Client-Side Cryptography: JWTs and secrets never leave your browser
HMAC Signature Verification
Decoded (Signature Unverified)
Active / Valid Exp
Header:
{
  "alg": "HS256",
  "typ": "JWT"
}
Payload Claims:
{
  "sub": "usr-9982",
  "name": "Alex Chen",
  "role": "admin",
  "iss": "auth.platform.io",
  "exp": 1999999999,
  "iat": 1680000000
}

Security & Verification Distinction

Decoding a token only extracts claims and does not prove authenticity. A token is only trustworthy once its signature is validated against the signing secret with standard Web Crypto.

JWTを検証する方法

  1. 1トークンを貼り付けます。
  2. 2シークレットキーを入力して署名の正当性を数学的に検証します。

Frequently Asked Questions

シークレットは安全ですか?

はい、ブラウザ内のみで処理され外部に流出しません。