2021-12-07 13:18:08 -05:00

68 lines
1.9 KiB
JavaScript

const { publicEncrypt, privateDecrypt, constants } = require('crypto')
const { oaepHashSupported } = require('../help/runtime_support')
const { KEYOBJECT } = require('../help/consts')
const { asInput } = require('../help/key_object')
const resolvePadding = (alg) => {
switch (alg) {
case 'RSA-OAEP':
case 'RSA-OAEP-256':
case 'RSA-OAEP-384':
case 'RSA-OAEP-512':
return constants.RSA_PKCS1_OAEP_PADDING
case 'RSA1_5':
return constants.RSA_PKCS1_PADDING
}
}
const resolveOaepHash = (alg) => {
switch (alg) {
case 'RSA-OAEP':
return 'sha1'
case 'RSA-OAEP-256':
return 'sha256'
case 'RSA-OAEP-384':
return 'sha384'
case 'RSA-OAEP-512':
return 'sha512'
default:
return undefined
}
}
const wrapKey = (padding, oaepHash, { [KEYOBJECT]: keyObject }, payload) => {
const key = asInput(keyObject, true)
return { wrapped: publicEncrypt({ key, oaepHash, padding }, payload) }
}
const unwrapKey = (padding, oaepHash, { [KEYOBJECT]: keyObject }, payload) => {
const key = asInput(keyObject, false)
return privateDecrypt({ key, oaepHash, padding }, payload)
}
const LENGTHS = {
RSA1_5: 0,
'RSA-OAEP': 592,
'RSA-OAEP-256': 784,
'RSA-OAEP-384': 1040,
'RSA-OAEP-512': 1296
}
module.exports = (JWA, JWK) => {
const algs = ['RSA-OAEP', 'RSA1_5']
if (oaepHashSupported) {
algs.splice(1, 0, 'RSA-OAEP-256', 'RSA-OAEP-384', 'RSA-OAEP-512')
}
algs.forEach((jwaAlg) => {
const padding = resolvePadding(jwaAlg)
const oaepHash = resolveOaepHash(jwaAlg)
JWA.keyManagementEncrypt.set(jwaAlg, wrapKey.bind(undefined, padding, oaepHash))
JWA.keyManagementDecrypt.set(jwaAlg, unwrapKey.bind(undefined, padding, oaepHash))
JWK.RSA.wrapKey[jwaAlg] = key => (key.use === 'enc' || key.use === undefined) && key.length >= LENGTHS[jwaAlg]
JWK.RSA.unwrapKey[jwaAlg] = key => key.private && (key.use === 'enc' || key.use === undefined) && key.length >= LENGTHS[jwaAlg]
})
}