74 lines
2.3 KiB
Plaintext
74 lines
2.3 KiB
Plaintext
import { COSECRV, COSEKEYS } from '../../cose.js';
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import { mapCoseAlgToWebCryptoAlg } from './mapCoseAlgToWebCryptoAlg.js';
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import { importKey } from './importKey.js';
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import { isoBase64URL } from '../index.js';
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import { getWebCrypto } from './getWebCrypto.js';
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/**
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* Verify a signature using an EC2 public key
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*/
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export async function verifyEC2(opts) {
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const { cosePublicKey, signature, data, shaHashOverride } = opts;
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const WebCrypto = await getWebCrypto();
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// Import the public key
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const alg = cosePublicKey.get(COSEKEYS.alg);
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const crv = cosePublicKey.get(COSEKEYS.crv);
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const x = cosePublicKey.get(COSEKEYS.x);
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const y = cosePublicKey.get(COSEKEYS.y);
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if (!alg) {
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throw new Error('Public key was missing alg (EC2)');
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}
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if (!crv) {
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throw new Error('Public key was missing crv (EC2)');
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}
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if (!x) {
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throw new Error('Public key was missing x (EC2)');
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}
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if (!y) {
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throw new Error('Public key was missing y (EC2)');
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}
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let _crv;
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if (crv === COSECRV.P256) {
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_crv = 'P-256';
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}
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else if (crv === COSECRV.P384) {
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_crv = 'P-384';
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}
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else if (crv === COSECRV.P521) {
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_crv = 'P-521';
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}
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else {
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throw new Error(`Unexpected COSE crv value of ${crv} (EC2)`);
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}
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const keyData = {
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kty: 'EC',
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crv: _crv,
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x: isoBase64URL.fromBuffer(x),
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y: isoBase64URL.fromBuffer(y),
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ext: false,
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};
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const keyAlgorithm = {
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/**
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* Note to future self: you can't use `mapCoseAlgToWebCryptoKeyAlgName()` here because some
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* leaf certs from actual devices specified an RSA SHA value for `alg` (e.g. `-257`) which
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* would then map here to `'RSASSA-PKCS1-v1_5'`. We always want `'ECDSA'` here so we'll
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* hard-code this.
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*/
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name: 'ECDSA',
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namedCurve: _crv,
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};
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const key = await importKey({
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keyData,
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algorithm: keyAlgorithm,
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});
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// Determine which SHA algorithm to use for signature verification
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let subtleAlg = mapCoseAlgToWebCryptoAlg(alg);
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if (shaHashOverride) {
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subtleAlg = mapCoseAlgToWebCryptoAlg(shaHashOverride);
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}
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const verifyAlgorithm = {
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name: 'ECDSA',
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hash: { name: subtleAlg },
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};
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return WebCrypto.subtle.verify(verifyAlgorithm, key, signature, data);
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}
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