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Workers – Web Crypto adds ML-KEM and ML-DSA support

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The Workers Web Crypto API now supports ML-KEM-768, ML-KEM-1024, ML-DSA-44, ML-DSA-65, and ML-DSA-87. ML-KEM establishes shared secrets, while ML-DSA signs and verifies data.

The opt-in API also adds key encapsulation and decapsulation methods, getPublicKey(), SubtleCrypto.supports(), and JSON Web Keys (JWKs) with the AKP key type.

Turn on the webcrypto_modern_algorithms compatibility flag to use these features:

{
  "$schema": "./node_modules/wrangler/config-schema.json",
  "compatibility_flags": [
    "webcrypto_modern_algorithms"
  ]
}
compatibility_flags = ["webcrypto_modern_algorithms"]

This example uses ML-KEM-768 to establish the same shared secret on both sides:

src/index.jsjs
const keyPair = await crypto.subtle.generateKey("ML-KEM-768", false, [
	"encapsulateBits",
	"decapsulateBits",
]);

if (!("publicKey" in keyPair)) {
	throw new Error("Expected an ML-KEM key pair");
}

const { sharedKey, ciphertext } = await crypto.subtle.encapsulateBits(
	"ML-KEM-768",
	keyPair.publicKey,
);

const recoveredSharedKey = await crypto.subtle.decapsulateBits(
	"ML-KEM-768",
	keyPair.privateKey,
	ciphertext,
);
src/index.tsts
const keyPair = await crypto.subtle.generateKey("ML-KEM-768", false, [
	"encapsulateBits",
	"decapsulateBits",
]);

if (!("publicKey" in keyPair)) {
	throw new Error("Expected an ML-KEM key pair");
}

const { sharedKey, ciphertext } = await crypto.subtle.encapsulateBits(
	"ML-KEM-768",
	keyPair.publicKey,
);

const recoveredSharedKey = await crypto.subtle.decapsulateBits(
	"ML-KEM-768",
	keyPair.privateKey,
	ciphertext,
);

Workers implements a subset of the evolving Modern Algorithms in the Web Cryptography API ↗︎ draft. ML-KEM-512 and the draft’s other algorithms are not supported. The API may change as the draft evolves.

For current algorithm and operation support, refer to Web Crypto supported algorithms.

Source: Cloudflare

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