src/EncryptedData.js

import * as asn1js from "asn1js";
import { getParametersValue, clearProps } from "pvutils";
import { getEngine } from "./common.js";
import EncryptedContentInfo from "./EncryptedContentInfo.js";
import Attribute from "./Attribute.js";
//**************************************************************************************
/**
 * Class from RFC5652
 */
export default class EncryptedData
{
	//**********************************************************************************
	/**
	 * Constructor for EncryptedData class
	 * @param {Object} [parameters={}]
	 * @property {Object} [schema] asn1js parsed value
	 */
	constructor(parameters = {})
	{
		//region Internal properties of the object
		/**
		 * @type {number}
		 * @description version
		 */
		this.version = getParametersValue(parameters, "version", EncryptedData.defaultValues("version"));
		/**
		 * @type {EncryptedContentInfo}
		 * @description encryptedContentInfo
		 */
		this.encryptedContentInfo = getParametersValue(parameters, "encryptedContentInfo", EncryptedData.defaultValues("encryptedContentInfo"));
		
		if("unprotectedAttrs" in parameters)
			/**
			 * @type {Array.<Attribute>}
			 * @description unprotectedAttrs
			 */
			this.unprotectedAttrs = getParametersValue(parameters, "unprotectedAttrs", EncryptedData.defaultValues("unprotectedAttrs"));
		//endregion
		
		//region If input argument array contains "schema" for this object
		if("schema" in parameters)
			this.fromSchema(parameters.schema);
		//endregion
	}
	//**********************************************************************************
	/**
	 * Return default values for all class members
	 * @param {string} memberName String name for a class member
	 */
	static defaultValues(memberName)
	{
		switch(memberName)
		{
			case "version":
				return 0;
			case "encryptedContentInfo":
				return new EncryptedContentInfo();
			case "unprotectedAttrs":
				return [];
			default:
				throw new Error(`Invalid member name for EncryptedData class: ${memberName}`);
		}
	}
	//**********************************************************************************
	/**
	 * Compare values with default values for all class members
	 * @param {string} memberName String name for a class member
	 * @param {*} memberValue Value to compare with default value
	 */
	static compareWithDefault(memberName, memberValue)
	{
		switch(memberName)
		{
			case "version":
				return (memberValue === 0);
			case "encryptedContentInfo":
				return ((EncryptedContentInfo.compareWithDefault("contentType", memberValue.contentType)) &&
				(EncryptedContentInfo.compareWithDefault("contentEncryptionAlgorithm", memberValue.contentEncryptionAlgorithm)) &&
				(EncryptedContentInfo.compareWithDefault("encryptedContent", memberValue.encryptedContent)));
			case "unprotectedAttrs":
				return (memberValue.length === 0);
			default:
				throw new Error(`Invalid member name for EncryptedData class: ${memberName}`);
		}
	}
	//**********************************************************************************
	/**
	 * Return value of asn1js schema for current class
	 * @param {Object} parameters Input parameters for the schema
	 * @returns {Object} asn1js schema object
	 */
	static schema(parameters = {})
	{
		//id-encryptedData OBJECT IDENTIFIER ::= { iso(1) member-body(2)
		//    us(840) rsadsi(113549) pkcs(1) pkcs7(7) 6 }
		
		//EncryptedData ::= SEQUENCE {
		//    version CMSVersion,
		//    encryptedContentInfo EncryptedContentInfo,
		//    unprotectedAttrs [1] IMPLICIT UnprotectedAttributes OPTIONAL }
		
		/**
		 * @type {Object}
		 * @property {string} [blockName]
		 * @property {string} [version]
		 * @property {string} [encryptedContentInfo]
		 * @property {string} [unprotectedAttrs]
		 */
		const names = getParametersValue(parameters, "names", {});
		
		return (new asn1js.Sequence({
			name: (names.blockName || ""),
			value: [
				new asn1js.Integer({ name: (names.version || "") }),
				EncryptedContentInfo.schema(names.encryptedContentInfo || {}),
				new asn1js.Constructed({
					optional: true,
					idBlock: {
						tagClass: 3, // CONTEXT-SPECIFIC
						tagNumber: 1 // [1]
					},
					value: [
						new asn1js.Repeated({
							name: (names.unprotectedAttrs || ""),
							value: Attribute.schema()
						})
					]
				})
			]
		}));
	}
	//**********************************************************************************
	/**
	 * Convert parsed asn1js object into current class
	 * @param {!Object} schema
	 */
	fromSchema(schema)
	{
		//region Clear input data first
		clearProps(schema, [
			"version",
			"encryptedContentInfo",
			"unprotectedAttrs"
		]);
		//endregion
		
		//region Check the schema is valid
		const asn1 = asn1js.compareSchema(schema,
			schema,
			EncryptedData.schema({
				names: {
					version: "version",
					encryptedContentInfo: {
						names: {
							blockName: "encryptedContentInfo"
						}
					},
					unprotectedAttrs: "unprotectedAttrs"
				}
			})
		);
		
		if(asn1.verified === false)
			throw new Error("Object's schema was not verified against input data for EncryptedData");
		//endregion
		
		//region Get internal properties from parsed schema
		this.version = asn1.result.version.valueBlock.valueDec;
		this.encryptedContentInfo = new EncryptedContentInfo({ schema: asn1.result.encryptedContentInfo });
		
		if("unprotectedAttrs" in asn1.result)
			this.unprotectedAttrs = Array.from(asn1.result.unprotectedAttrs, element => new Attribute({ schema: element }));
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convert current object to asn1js object and set correct values
	 * @returns {Object} asn1js object
	 */
	toSchema()
	{
		//region Create array for output sequence
		const outputArray = [];
		
		outputArray.push(new asn1js.Integer({ value: this.version }));
		outputArray.push(this.encryptedContentInfo.toSchema());
		
		if("unprotectedAttrs" in this)
		{
			outputArray.push(new asn1js.Constructed({
				optional: true,
				idBlock: {
					tagClass: 3, // CONTEXT-SPECIFIC
					tagNumber: 1 // [1]
				},
				value: Array.from(this.unprotectedAttrs, element => element.toSchema())
			}));
		}
		//endregion
		
		//region Construct and return new ASN.1 schema for this object
		return (new asn1js.Sequence({
			value: outputArray
		}));
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convertion for the class to JSON object
	 * @returns {Object}
	 */
	toJSON()
	{
		const _object = {
			version: this.version,
			encryptedContentInfo: this.encryptedContentInfo.toJSON()
		};
		
		if("unprotectedAttrs" in this)
			_object.unprotectedAttrs = Array.from(this.unprotectedAttrs, element => element.toJSON());
		
		return _object;
	}
	//**********************************************************************************
	/**
	 * Create a new CMS Encrypted Data content
	 * @param {Object} parameters Parameters neccessary for encryption
	 * @returns {Promise}
	 */
	encrypt(parameters)
	{
		//region Check for input parameters
		if((parameters instanceof Object) === false)
			return Promise.reject("Parameters must have type \"Object\"");
		//endregion
		
		//region Get cryptographic engine
		const engine = getEngine();
		if(typeof engine === "undefined")
			return Promise.reject("Unable to initialize cryptographic engine");
		//endregion
		
		//region Set "contentType" parameter
		parameters.contentType = "1.2.840.113549.1.7.1"; // "data"
		//endregion
		
		if("encryptEncryptedContentInfo" in engine.subtle)
		{
			return engine.subtle.encryptEncryptedContentInfo(parameters).then(result =>
			{
				this.encryptedContentInfo = result;
			});
		}
		
		return Promise.reject(`No support for "encryptEncryptedContentInfo" in current crypto engine ${engine.name}`);
	}
	//**********************************************************************************
	/**
	 * Create a new CMS Encrypted Data content
	 * @param {Object} parameters Parameters neccessary for encryption
	 */
	decrypt(parameters)
	{
		//region Check for input parameters
		if((parameters instanceof Object) === false)
			return Promise.reject("Parameters must have type \"Object\"");
		//endregion
		
		//region Get cryptographic engine
		const engine = getEngine();
		if(typeof engine === "undefined")
			return Promise.reject("Unable to initialize cryptographic engine");
		//endregion
		
		//region Set "encryptedContentInfo" value
		parameters.encryptedContentInfo = this.encryptedContentInfo;
		//endregion
		
		if("decryptEncryptedContentInfo" in engine.subtle)
			return engine.subtle.decryptEncryptedContentInfo(parameters);
		
		return Promise.reject(`No support for "decryptEncryptedContentInfo" in current crypto engine ${engine.name}`);
	}
	//**********************************************************************************
}
//**************************************************************************************