text: const generateIV = require('../help/generate_iv')
  const base64url = require('../help/base64url')
  
  module.exports = (JWA, JWK) => {
    ['A128GCMKW', 'A192GCMKW', 'A256GCMKW'].forEach((jwaAlg) => {
      const encAlg = jwaAlg.substr(0, 7)
      const size = parseInt(jwaAlg.substr(1, 3), 10)
      const encrypt = JWA.encrypt.get(encAlg)
      const decrypt = JWA.decrypt.get(encAlg)
  
      if (encrypt && decrypt) {
        JWA.keyManagementEncrypt.set(jwaAlg, (key, payload) => {
          const iv = generateIV(jwaAlg)
          const { ciphertext, tag } = encrypt(key, payload, { iv })
          return {
            wrapped: ciphertext,
            header: { tag: base64url.encodeBuffer(tag), iv: base64url.encodeBuffer(iv) }
          }
        })
        JWA.keyManagementDecrypt.set(jwaAlg, decrypt)
        JWK.oct.wrapKey[jwaAlg] = JWK.oct.unwrapKey[jwaAlg] = key => (key.use === 'enc' || key.use === undefined) && key.length === size
      }
    })
  }
  