# hmac Published articles for hmac. This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## HTTP Message Signatures with curl DevFeed: [HTTP Message Signatures with curl]() Original publisher: [Read original article]() Author: Daniel Stenberg Published: 2026-07-27T06:55:03Z Content type: release Language: en Sources: [Daniel Stenberg]() Topics: [cURL](), [HTTP](), [Authentication]() Tags: [curl](), [curl-and-libcurl](), [digital-signatures](), [ed25519](), [experimental](), [git](), [hmac](), [http](), [production](), [release]() ### AI overview curl experimentally supports HTTP Message Signatures based on RFC 9421, allowing users to sign selected HTTP request components with ed25519 or hmac-sha256 through new command-line and libcurl options. The feature must be explicitly enabled, is discouraged for production use, and is planned for curl 8.22.0. ### Source excerpt The recently published RFC 9421 describes how to do HTTP Message Signatures, and starting just now, curl experimentally supports them. Message Signatures The specification describes this as a mechanism for creating, encoding, and verifying digital signatures or message authentication codes over components of an HTTP message. It is a way to verify that selected parts ... Continue reading HTTP Message Signatures with curl -> ## A Developer's Guide to HMAC Validation for Adyen Webhooks DevFeed: [A Developer's Guide to HMAC Validation for Adyen Webhooks]() Original publisher: [Read original article]() Author: Adyen Published: 2025-06-16T09:38:43Z Content type: tutorial Language: en Sources: [Adyen Tech]() Topics: [Security](), [integrity](), [payload](), [implementation](), [JSON](), [HTTP](), [Testing](), [Open Source]() Tags: [adyen](), [api](), [authentication](), [best-practices](), [developer](), [encryption](), [guide](), [hmac](), [http](), [implementation](), [integration](), [json](), [open-source](), [payload](), [payments](), [security](), [testing](), [validation](), [webhooks]() ### AI overview This guide explains how Adyen uses HMAC signatures to protect the authenticity and integrity of webhook payloads. It distinguishes payment webhooks, which include the signature in the JSON payload, from other webhooks, which provide it in an HTTP header, and discusses custom validation and Adyen's open-source libraries. ### Source excerpt By Beppe Catanese, Developer Relations, AdyenImage by authorIntroduction When it comes to payments, security isn't optional -- it's essential. If you're integrating with Adyen, ensuring the incoming webhooks' authenticity and integrity is very important. That's where Hash-based Message Authentication Code (HMAC) plays a critical role in securing your Adyen integration. Image by author Implementing, testing, and troubleshooting HMAC validation can be challenging. This guide explains how HMAC validation works, highlights the challenges, and provides tools and best practices for secure and reliable implementation. HMAC at Adyen All Adyen webhooks use HMAC to ensure the integrity and authenticity of the payloads delivered to your integrations. The HMAC key should be enabled when setting up a new webhook (either in the Customer Area Webhook page or using the Management API). Adyen will use the HMAC key to sign the payload by creating an HMAC signature. You must validate the HMAC signature, delivered with the webhook, using the same HMAC key. Adyen webhooks fall into two main categories, each with its approach to HMAC implementation. Let's explore the two scenarios. 1. Payments Webhooks For payments-related webhooks, the calculation of the signature involves using a subset of fields, and it's embedded directly within the JSON payload under the `additionalData` object: { "live":"false", "notificationItems":[ { "NotificationRequestItem":{ "additionalData":{ "hmacSignature":"+JWKfq4ynALK+FFzGgHnp1jSMQJMBJeb87dlph24sXw=" }, ... } } ] }2. Other Webhooks (Adyen for Platforms, Management) For non-payment webhooks, the signature is calculated using the entire JSON payload. Instead of being included in the payload itself, the signature is provided in the HTTP Header `hmacSignature`: content-length: 1614 content-type: application/json hmacsignature: SMQZFOq3oIdugmf97u9TB+5256jjXgUX3MRjK+RlGNQ=Implementing HMAC Validation Developers have two options for implementing HMAC validation: ## Practical Cryptography Recommendations for Developers DevFeed: [Practical Cryptography Recommendations for Developers]() Original publisher: [Read original article]() Published: 2018-04-03T19:25:00Z Content type: opinion Language: en Sources: [Latacora]() Topics: [Cryptography](), [Encryption](), [Security](), [ChaCha](), [passwords](), [Embedded Systems]() Tags: [cryptographic](), [cryptography](), [hmac](), [password](), [security](), [stream]() ### AI overview The article gives conservative cryptography guidance for developers, recommending simple, conventional, analyzable choices. It discusses authenticated encryption, password AKEs, KMS, ChaCha20-Poly1305, AES-GCM, and nonce management, while noting that more specialized systems may require different designs. ### Source excerpt We're less interested in empowering developers and a lot more pessimistic about the prospects of getting this stuff right. There are, in the literature and in the most sophisticated modern systems, "better" answers for many of these items. If you're building for low-footprint embedded systems, you can use STROBE and a sound, modern, authenticated encryption stack entirely out of a single SHA-3-like sponge constructions. You can use NOISE to build a secure transport protocol with its own AKE. Speaking of AKEs, there are, like, 30 different password AKEs you could choose from. ## Thought experiment on protocols and noise DevFeed: [Thought experiment on protocols and noise]() Original publisher: [Read original article]() Author: Nate Lawson Published: 2014-11-04T18:42:52Z Content type: opinion Language: en Sources: [rdist]() Topics: [Security](), [Protocol (disambiguation)](), [sha-256](), [hash]() Tags: [crypto](), [hash](), [hmac](), [network](), [protocol](), [protocols](), [security](), [sha-256]() ### AI overview A security thought experiment examines how to respond when an HMAC does not verify, including whether comparing MAC differences could distinguish network noise from tampering. It questions the security risks of exposing error details or accepting messages with altered MAC bits. ### Source excerpt I hesitate to call this an interview question because I don't think on-the-spot puzzle solving equates to a good engineering hire. On the other hand, I try to explore some simple thought experiments with candidates that have a security background. One of these involves a protocol that has messages authenticated by an HMAC. There's a message ... Continue reading Thought experiment on protocols and noise