{"uid":"cap_JR3zzB4pS3cJHEJ02lf6i","slug":"hmac-blake2b-512-base64url-generator-0e8eba9b","name":"HMAC-BLAKE2b-512 Base64URL Generator","description":"Call when an agent needs an HMAC-blake2b512 of text with a caller-supplied key, encoded as base64url. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/hmac-blake2b512-base64url first.","url":"https://agentshelf.syntexa.ch/v1/hmac-blake2b512-base64url?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"key":{"type":"string","examples":["secret"],"maxLength":512,"minLength":1,"description":"HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored."},"text":{"type":"string","examples":["hello"],"maxLength":100000,"minLength":1,"description":"Message to digest. For raw-hex SKUs this is hex bytes; for utf16 or latin1 SKUs it is decoded with that encoding. Otherwise it is UTF-8 text."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_cF5DsnkBVI8dXZgZ6mAWa","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes an HMAC-BLAKE2b-512 digest of input text using a caller-supplied key and returns the result encoded as base64url","exampleAgentPrompt":"Compute an HMAC-BLAKE2b-512 signature of the text 'order_id=42&amount=100' using the key 'my-secret-key' and give me the result as a base64url string.","exampleUseCases":[{"title":"Webhook payload integrity verification","prompt":"Sign the webhook payload 'user_id=99&event=purchase&timestamp=1720000000' with the secret key 'wh_secret_abc123' using HMAC-BLAKE2b-512, and give me the base64url digest so I can attach it as a signature header."},{"title":"API request token generation","prompt":"I need to generate an HMAC-BLAKE2b-512 authentication token for the string 'GET /api/orders?page=1' using the key 'api-signing-key-xyz', encoded as base64url — can you do that?"},{"title":"Data tamper detection tagging","prompt":"Create an HMAC-BLAKE2b-512 tag for the text 'record:{\"id\":5,\"value\":\"approved\"}' with the key 'integrity-check-key-2024' and return it base64url-encoded so I can store it alongside the record."}],"resultDescription":"A base64url-encoded string representing the HMAC-BLAKE2b-512 digest of the input text computed with the provided key. The result is a fixed-length cryptographic MAC suitable for integrity checking, authentication, or signing workflows.","failureModes":["Missing or empty 'key' field returns a validation error","Missing or empty 'text' field returns a validation error","Key exceeding 512 characters or text exceeding 100,000 characters triggers a length validation error","Payment failure (insufficient USDC balance or x402 protocol error) results in a 402 response","Network or server error returns a 5xx response with no digest"],"whenToPreferThis":"Choose this endpoint when you need HMAC using the BLAKE2b-512 hash function specifically — which offers higher speed and security than HMAC-SHA256 in many contexts — and require the output in base64url encoding (URL-safe, no padding issues). Prefer over SHA-based HMAC endpoints when BLAKE2b compatibility is required. Use the free sandbox POST /v1/sandbox/hmac-blake2b512-base64url for testing before committing to the paid endpoint.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-01T00:49:03.443Z","isFirstParty":false,"canonicalSlug":"hmac-blake2b-512-base64url-generator-0e8eba9b"}