Articles · Cross-category

Correlation, ciphers, and email auth tools

Another hundred tools landed across correlation and finance math, classical ciphers, JWT display decode, Gray code, SPF/DMARC header parsers, calendar week math, and retail check-digit generators. Start here when you know the job, not the route name.

The newest Toolcore batch adds another hundred browser-local pages in correlation and finance math, classical ciphers and readability scores, JWT display-only decode, Gray code and Base58Check, SPF/DMARC and HTTP header splits, calendar week math, and check-digit generators for retail barcodes. Use this map when you know the job—not when you want to scroll the full catalog.

Correlation, regression, and finance

Ciphers, readability, and run-length text

Classical ciphers and readability formulas run locally on pasted prose—no upload, no server round-trip.

JWT decode, checksums, Gray code

Email auth headers, calendar math, check digits

Browse Math, Writing, Security, Encoding, Protocol, Schedule, and Identity tabs on the home catalog for the full list. For the prior statistics batch, see the statistics and text analysis guide.

Common use cases

  • Compare two pasted metric lists with Spearman ρ or sample covariance before building a dashboard.
  • Decode JWT header JSON or split SPF/DMARC TXT records from DNS without pasting tokens into chat.
  • Generate UPC-A or EAN-13 check digits for mock catalog data and barcode homework.

Common mistakes to avoid

  • Treating JWT decode pages as verification

    Header and payload tools display Base64url JSON only—they do not validate signatures or trust claims.

  • Using demo hash pages as certified algorithms

    Educational digest demos (HAS-160, Whirlpool-style) illustrate output shape—they are not audited national-standard implementations.

  • Expecting live identifier lookups

    UPC, EAN, and Luhn generators compute check digits locally—they do not query GS1 or card issuer directories.

FAQ

How does this batch differ from the statistics batch?

That guide covered sample mean, binomial probability, and HTTP Accept parse. This set adds correlation and finance formulas, classical ciphers, JWT display decode, Gray code, SPF/DMARC splits, and retail check-digit tools.

Are all 100 pages linked here?

No—each section points to representative tools. Browse the home catalog tabs for the full list.

Can agents prefill these tools?

Single text fields often accept q or qb. Multi-field date, number, and key+list tools open without URL prefill.