encrypted_data_key.ts

// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

import {
  readOnlyBinaryProperty,
  readOnlyProperty,
  frozenClass,
} from './immutable_class'
import { needs } from './needs'

/*
 * This public interface to the encrypted data key (EDK) objects is provided for
 * developers of CMMs and keyrings only. If you are a user of the AWS Encryption
 * SDK and you are not developing your own CMMs and/or keyrings, you do not
 * need to use it and you should not do so.
 */

/* The providerInfo is technically bytes.
 * That most keyrings chose to use store this data as a string just convenience.
 * It is easy and manageable to store pass utf8 strings around,
 * however some keyrings may chose to use this field to store binary data.
 * The raw AES keyrings are a notable example.
 * To complicate matters, utf8 is "destructive" because of multi-byte characters.
 * binary != decodeUtf8(encodeUtf8(binary))
 * Any binary value above 127 will be interpreted as a multi-byte character.
 * To support the simplicity of strings but the extensibility of binary
 * I chose default to strings, but offer an optional binary property.
 * All serialize/deserialize operations will prefer the binary value if present.
 *
 * *It is not required that the providerInfo string "equal" the binary rawInfo*
 *
 */
export interface IEncryptedDataKey
  extends Readonly<{
    providerInfo: string
    providerId: string
    encryptedDataKey: Uint8Array
    rawInfo?: Uint8Array
  }> {}

export class EncryptedDataKey {
  declare readonly providerInfo: string
  declare readonly providerId: string
  declare readonly encryptedDataKey: Uint8Array
  declare readonly rawInfo?: Uint8Array

  constructor(edkInput: IEncryptedDataKey) {
    const { providerInfo, providerId, encryptedDataKey, rawInfo } = edkInput
    needs(
      typeof providerInfo === 'string' &&
        providerInfo &&
        typeof providerId === 'string' &&
        providerId &&
        encryptedDataKey instanceof Uint8Array &&
        encryptedDataKey.byteLength,
      'Malformed encrypted data key'
    )

    readOnlyProperty(this, 'providerInfo', providerInfo)
    readOnlyProperty(this, 'providerId', providerId)
    readOnlyBinaryProperty(this, 'encryptedDataKey', encryptedDataKey)
    if (rawInfo instanceof Uint8Array) {
      readOnlyBinaryProperty(this, 'rawInfo', rawInfo)
    } else {
      readOnlyProperty(this, 'rawInfo', undefined)
    }

    Object.setPrototypeOf(this, EncryptedDataKey.prototype)
    Object.freeze(this)
  }
}

frozenClass(EncryptedDataKey)