Web Crypto API Capabilities Inspector
Web Crypto API Capabilities Inspector: Queries available cryptographic primitives: AES-GCM, RSA-PSS, ECDSA (P-256, P-384), SHA-256, and HKDF.
About this web crypto api capabilities inspector
Web Crypto API Capabilities Inspector — browser-based utility.
How this tool works
Implements client-side Web Crypto API Capabilities Inspector operations. Queries available cryptographic primitives: AES-GCM, RSA-PSS, ECDSA (P-256, P-384), SHA-256, and HKDF specifically designed for a security developer audits the browser's hardware cryptographic capabilities and algorithm support.
- Key Derivation & CSPRNG Nonce Generation: Derives cryptographic keys from passphrases via PBKDF2 with random salts and generates unique IV nonces.
- Authenticated Encryption (AEAD): Encrypts plaintext blocks and computes an authentication tag to protect against ciphertext tampering.
- Container Formatting: Packages salt, IV, ciphertext, and auth tag into standardized Base64 or JSON envelopes.
- Decryption & Tamper Verification: Verifies the authentication tag before decrypting; throws immediate integrity errors if data was modified.
Worked example
Scenario: Probe the four Web Crypto operations exposed by the current page context.
Sample input:
Processing: Check secure context and random APIs, then attempt SHA-256, AES-GCM, HMAC and ECDSA P-256 operations.
Illustrative output:
Limits and verification
Never reuses an Initialization Vector (IV) with the same key (IV reuse in GCM mode destroys authenticity and leaks plaintext). Passphrases cannot be recovered if lost, as no backdoor or recovery key exists.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the Web Crypto API Capabilities Inspector workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
What does Web Crypto Inspector test?+
It reports secure-context status, availability of crypto.subtle and crypto.getRandomValues, then attempts SHA-256 digest, AES-GCM key generation, HMAC key generation, and ECDSA P-256 key generation.
What did the browser fixture verify?+
On the frozen HTTPS-equivalent local candidate context, secureContext, subtleCryptoAvailable and randomValuesAvailable were true, and all four listed algorithm attempts returned true.
Does available mean every Web Crypto operation works?+
No. This is a small capability probe. It does not test every algorithm, key import/export format, browser policy, hardware-backed key, quota, cipher vector, or failure mode.
Can this diagnose a remote site?+
No. It inspects the current page context only. Headers, origin trust, enterprise policy, extensions, secure transport and another browser can produce different capability results.