Security & API
Cryptographic Hash, HMAC & UUID Generator
Calculate SHA-256, SHA-512, and HMAC signatures, encode/decode UTF-8 Base64, verify release checksums, and generate bulk UUID v4 strings with 100% in-browser privacy.
43 chars43 bytes
SHA-256 (Hex)
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SHA-256 (Base64)
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SHA-512 (Hex)
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SHA-384 (Hex)
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SHA-1 (Hex - Legacy)
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Verify & Compare Checksum
Paste an expected hash from an open-source download or security bulletin to verify integrity:
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How to use
- 1Select a tab: Hashes (SHA-256/512), HMAC Signer, Base64 Encoder, or UUID Generator.
- 2For Hashes: Type or paste your text to see real-time updates for SHA-256, SHA-512, SHA-384, and SHA-1.
- 3For HMAC: Enter your secret signing key and message payload to generate standard HMAC-SHA256 signatures.
- 4For Base64: Easily switch between UTF-8 text encoding and Base64 decoding.
- 5For UUID: Choose your batch size (1 to 20), toggle uppercase or hyphens, and click "Copy All".
Frequently asked questions
Are my passwords or sensitive payloads uploaded to any server?
Never. All calculations use the browser's native Web Cryptography API (window.crypto.subtle). Your inputs, secret signing keys, and generated hashes never leave your browser memory and are completely safe from network inspection.
What is the difference between SHA-256 Hex and SHA-256 Base64?
Both represent the exact same 256-bit cryptographic digest. Hexadecimal encoding uses 64 characters (0-9, a-f) where each byte takes two characters. Base64 represents the 32 bytes using 44 characters (A-Z, a-z, 0-9, +, /, =), which is more compact for HTTP headers and JSON bodies.
What is HMAC and when should I use it?
HMAC (Hash-based Message Authentication Code) combines a cryptographic hash function with a secret shared key. It is widely used in REST APIs and webhooks (e.g. Stripe, GitHub, AWS SigV4) to verify both data integrity and message authenticity, ensuring payloads were not tampered with in transit.
Are the UUIDs generated cryptographically secure?
Yes. UUID v4 values are generated using crypto.randomUUID(), which relies on the operating system's cryptographically secure pseudo-random number generator (CSPRNG). With 122 bits of randomness, the probability of collision is virtually zero.
How do I verify a downloaded file's checksum with this tool?
Paste your content into the Input area, copy the expected checksum from the release page into the "Verify & Compare Checksum" box, and the tool will instantly confirm if any SHA-256, SHA-512, or SHA-1 hashes match.
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