Security & Crypto Tools

Hash generators, certificate and CSR decoders, SPF/DMARC/DKIM checkers and security header analysers - all client-side.

Security tools split into two halves on this site: things you compute locally, and things that need to look something up. The local half - hashes, SRI hashes, CSR decoding, password entropy - never sends your input anywhere, which is the only acceptable behaviour when the input is a private key, a password or an internal certificate. The lookup half - domain security checks and security header analysis - fetches public DNS records or the headers of a URL you name, and says so explicitly.

Typical workflows: generate a SHA-256 to verify a download, then look the hash up in the hash-check.com database to see whether that exact file is known; decode a CSR before you hand it to a certificate authority so you catch the wrong subject or key type first; check a domain's SPF, DMARC and DKIM records when mail is landing in spam; and scan your own response headers after a deploy to confirm HSTS, CSP and the frame options actually made it out.

Guidance that saves time: entropy is not the same as strength when the password is a dictionary phrase, DKIM failures are usually selector mismatches rather than missing records, and a CSR cannot be "fixed" - if the subject is wrong you generate a new key and a new request. Each tool says which of these applies to what you just pasted rather than leaving you to search.

7 tools in this category

• Hash Generator — SHA-1/256/384/512 hashes of text or files.
• Hash Checker — Look up a file hash in the hash-check.com database.
• Password Entropy Calculator — Estimate password strength with a realistic cracking model.
• Email Domain Security Checker — Check a domain's SPF, DMARC & DKIM via DNS-over-HTTPS with a spoofing-risk score, the
• Security Headers Checker — Check CSP, HSTS, XFO, XCT, Referrer-Policy & Permissions-Policy with an A+–F weighted
• Certificate Signing Request Decoder — Decode a CSR (PKCS#10) in your browser: subject DN, RSA/EC/Ed25519 key details, SAN
• Subresource Integrity Generator — Generate SRI hashes (SHA-256/384/512) for JS & CSS from pasted code, a URL or an

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