HMAC Component Overview

📖 Introduction

cCryptoHMAC is a Windows CryptoAPI-based HMAC (Hash-based Message Authentication Code) implementation that supports HMAC-SHA1 and HMAC-SHA256 algorithms.

✨ Key Features

Feature	Description
Standard HMAC	Implemented according to RFC 2104 standard
Dual Algorithm Support	HMAC-SHA1, HMAC-SHA256
Flexible Keys	Supports keys in string, byte array, Hex, Base64 formats
Chainable API	Fluent API design with method chaining
Multiple Outputs	Supports Hex, Base64, byte array output
Auto Key Processing	Automatic key length handling (auto-hash if exceeds block size)

🚀 Quick Start

Create Instance

Dim Hmac As New cCryptoHMAC

Simple Computation

' Compute HMAC (default SHA256)
Dim result As String
result = Hmac.Compute("data to sign", "secret-key")
Debug.Print result

Chainable Call

' Use chainable call
Dim result As String
result = Hmac.Mode(HMAC_ALG_SHA256) _
            .Secret("secret-key") _
            .DataString("data to sign") _
            .ReturnHex()

📋 Supported Algorithms

Algorithm	Enum Value	Block Size	Description
HMAC-SHA1	HMAC_ALG_SHA1	64 bytes	Good compatibility
HMAC-SHA256	HMAC_ALG_SHA256	64 bytes	High security (recommended)

🔐 HMAC Use Cases

HMAC is mainly used for:

1. API Request Signing - Verify request integrity and identity
2. Message Authentication - Ensure message has not been tampered with
3. Data Integrity Verification - Integrity verification with keys
4. JWT Signing - Signature part of JSON Web Tokens

🔗 Related Documentation

• methods.md - Methods detailed reference

---

Last Updated: 2026-05-17