{"$schema":"https://toolsly.tools/schemas/tool-manifest-v1.json","generated":"2026-06-27T12:01:38.457Z","discovery":{"catalog":"https://toolsly.tools/tools.json","llmsTxt":"https://toolsly.tools/llms.txt","sitemap":"https://toolsly.tools/sitemap.xml"},"relatedTools":[{"slug":"dukpt-pin-block-calculator","name":"DUKPT PIN Block Calculator","url":"https://toolsly.tools/dukpt-pin-block-calculator"},{"slug":"iban-validator","name":"IBAN Validator","url":"https://toolsly.tools/iban-validator"},{"slug":"luhn-check","name":"Luhn Check","url":"https://toolsly.tools/luhn-check"},{"slug":"discount-calculator","name":"Discount Calculator","url":"https://toolsly.tools/discount-calculator"},{"slug":"card-brand-identifier","name":"Card Brand Identifier","url":"https://toolsly.tools/card-brand-identifier"},{"slug":"emv-tag-lookup","name":"EMV Tag Lookup","url":"https://toolsly.tools/emv-tag-lookup"},{"slug":"swift-bic-validator","name":"SWIFT / BIC Validator","url":"https://toolsly.tools/swift-bic-validator"},{"slug":"crc32-checksum","name":"CRC32 Checksum Calculator","url":"https://toolsly.tools/crc32-checksum"}],"kind":"utility","slug":"kcv-calculator","name":"KCV Calculator (3DES)","description":"Compute the Key Check Value (KCV) of a single, double or triple length DES key by encrypting 8 bytes of zeros.","longDescription":"Standard payments-industry KCV: ECB-encrypt a block of 0x00 with the key under 3DES and take the first 3 (or 6) bytes of the ciphertext. Single-length keys are repeated three times; double-length keys use the K1K2K1 derivation. Runs entirely in your browser via crypto-js — your key is never transmitted.","category":"payment","categoryName":"Payment & cards","keywords":["kcv calculator","kcv calculator online","kcv calculator free","key check value","3des kcv","tdes kcv","des key kcv","kcv tool","calculate kcv","kcv 3 bytes","kcv 6 bytes","payment hsm kcv"],"badge":"Calculator","url":"https://toolsly.tools/kcv-calculator","inputs":[{"type":"text","key":"key","label":"Key (hex)","placeholder":"0123456789ABCDEF FEDCBA9876543210","monospace":true,"help":"16 (single), 32 (double) or 48 (triple) hex digits. Whitespace is ignored."},{"type":"select","key":"length","label":"KCV length","defaultValue":"3","choices":[{"value":"3","label":"3 bytes (6 hex digits) — standard"},{"value":"6","label":"6 bytes (12 hex digits)"}]}],"outputs":[{"key":"kcv","label":"KCV"},{"key":"keyForm","label":"Key length"}],"invocation":{"webUi":"https://toolsly.tools/kcv-calculator","api":null,"notes":"Currently invoked via the web UI at `webUi`. Inputs are form fields; outputs are structured text values. A remote MCP/REST API is planned."}}