perldoc > Digest::HMAC

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🏷️ NAME

Digest::HMAC - Keyed-Hashing for Message Authentication

🚀 Quick Reference

Use Case	Command	Description
Functional HMAC 🧪	hmac($data, $key, \&myhash)	Compute HMAC with a given hash function
Functional HMAC (hex) 🧪	hmac_hex($data, $key, \&myhash)	Compute HMAC and return hex string
OO style instantiation 🧱	Digest::HMAC->new($key, "Digest::MyHash")	Create HMAC object with key and digest class
Add data ➕	$hmac->add($data)	Feed data to the HMAC object
Add file data 📁	$hmac->addfile(*FILE)	Feed data from a filehandle
Binary digest 🔒	$hmac->digest	Get the raw binary digest
Hex digest 🔢	$hmac->hexdigest	Get the digest as a hex string
Base64 digest 📦	$hmac->b64digest	Get the digest as a Base64 string
Optional blocksize 🧩	Digest::HMAC->new($key, "Digest::Foo", $blocksize)	Specify custom compression block size

📝 SYNOPSIS

# Functional style
use Digest::HMAC qw(hmac hmac_hex);
$digest = hmac($data, $key, \&myhash);
print hmac_hex($data, $key, \&myhash);

# OO style
use Digest::HMAC;
$hmac = Digest::HMAC->new($key, "Digest::MyHash");

$hmac->add($data);
$hmac->addfile(*FILE);

$digest = $hmac->digest;
$digest = $hmac->hexdigest;
$digest = $hmac->b64digest;

📖 DESCRIPTION

HMAC is used for message integrity checks 🔐 between two parties that share a secret key 🔑, and works in combination with some other Digest algorithm, usually MD5 or SHA-1. The HMAC mechanism is described in RFC 2104.

HMAC follow the common "Digest::" interface, but the constructor takes the secret key and the name of some other simple "Digest::" as argument.

The hmac() and hmac_hex() functions and the Digest::HMAC->new() constructor takes an optional 📦 $blocksize argument as well. The HMAC algorithm assumes the digester to hash by iterating a basic compression function on blocks of data and the $blocksize should match the byte-length of such blocks.

The default $blocksize is 64 which is suitable for the MD5 and SHA-1 digest functions. For stronger algorithms the blocksize probably needs to be increased.

🔗 SEE ALSO

• 📘 Digest::HMAC_MD5
• 📘 Digest::HMAC_SHA1
• 📄 RFC 2104

👤 MAINTAINER

Andrew Rodland <arodland AT cpan.org>

👥 ORIGINAL AUTHORS

Graham Barr <gbarr AT ti.com>, Gisle Aas <gisle AT aas.no>

🏷️ NAME 🚀 Quick Reference 📝 SYNOPSIS 📖 DESCRIPTION 🔗 SEE ALSO 👤 MAINTAINER 👥 ORIGINAL AUTHORS