src/PrivateKeyInfo.js

import * as asn1js from "asn1js";
import { getParametersValue, clearProps } from "pvutils";
import AlgorithmIdentifier from "./AlgorithmIdentifier.js";
import Attribute from "./Attribute.js";
import ECPrivateKey from "./ECPrivateKey.js";
import RSAPrivateKey from "./RSAPrivateKey.js";
//**************************************************************************************
/**
 * Class from RFC5208
 */
export default class PrivateKeyInfo
{
	//**********************************************************************************
	/**
	 * Constructor for PrivateKeyInfo 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", PrivateKeyInfo.defaultValues("version"));
		/**
		 * @type {AlgorithmIdentifier}
		 * @description privateKeyAlgorithm
		 */
		this.privateKeyAlgorithm = getParametersValue(parameters, "privateKeyAlgorithm", PrivateKeyInfo.defaultValues("privateKeyAlgorithm"));
		/**
		 * @type {OctetString}
		 * @description privateKey
		 */
		this.privateKey = getParametersValue(parameters, "privateKey", PrivateKeyInfo.defaultValues("privateKey"));

		if("attributes" in parameters)
			/**
			 * @type {Array.<Attribute>}
			 * @description attributes
			 */
			this.attributes = getParametersValue(parameters, "attributes", PrivateKeyInfo.defaultValues("attributes"));

		if("parsedKey" in parameters)
			/**
			 * @type {ECPrivateKey|RSAPrivateKey}
			 * @description Parsed public key value
			 */
			this.parsedKey = getParametersValue(parameters, "parsedKey", PrivateKeyInfo.defaultValues("parsedKey"));
		//endregion

		//region If input argument array contains "schema" for this object
		if("schema" in parameters)
			this.fromSchema(parameters.schema);
		//endregion
		//region If input argument array contains "json" for this object
		if("json" in parameters)
			this.fromJSON(parameters.json);
		//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 "privateKeyAlgorithm":
				return new AlgorithmIdentifier();
			case "privateKey":
				return new asn1js.OctetString();
			case "attributes":
				return [];
			case "parsedKey":
				return {};
			default:
				throw new Error(`Invalid member name for PrivateKeyInfo 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 = {})
	{
		//PrivateKeyInfo ::= SEQUENCE {
		//    version Version,
		//    privateKeyAlgorithm AlgorithmIdentifier {{PrivateKeyAlgorithms}},
		//    privateKey PrivateKey,
		//    attributes [0] Attributes OPTIONAL }
		//
		//Version ::= INTEGER {v1(0)} (v1,...)
		//
		//PrivateKey ::= OCTET STRING
		//
		//Attributes ::= SET OF Attribute

		/**
		 * @type {Object}
		 * @property {string} [blockName]
		 * @property {string} [version]
		 * @property {string} [privateKeyAlgorithm]
		 * @property {string} [privateKey]
		 * @property {string} [attributes]
		 */
		const names = getParametersValue(parameters, "names", {});

		return (new asn1js.Sequence({
			name: (names.blockName || ""),
			value: [
				new asn1js.Integer({ name: (names.version || "") }),
				AlgorithmIdentifier.schema(names.privateKeyAlgorithm || {}),
				new asn1js.OctetString({ name: (names.privateKey || "") }),
				new asn1js.Constructed({
					optional: true,
					idBlock: {
						tagClass: 3, // CONTEXT-SPECIFIC
						tagNumber: 0 // [0]
					},
					value: [
						new asn1js.Repeated({
							name: (names.attributes || ""),
							value: Attribute.schema()
						})
					]
				})
			]
		}));
	}
	//**********************************************************************************
	/**
	 * Convert parsed asn1js object into current class
	 * @param {!Object} schema
	 */
	fromSchema(schema)
	{
		//region Clear input data first
		clearProps(schema, [
			"version",
			"privateKeyAlgorithm",
			"privateKey",
			"attributes"
		]);
		//endregion
		
		//region Check the schema is valid
		const asn1 = asn1js.compareSchema(schema,
			schema,
			PrivateKeyInfo.schema({
				names: {
					version: "version",
					privateKeyAlgorithm: {
						names: {
							blockName: "privateKeyAlgorithm"
						}
					},
					privateKey: "privateKey",
					attributes: "attributes"
				}
			})
		);

		if(asn1.verified === false)
			throw new Error("Object's schema was not verified against input data for PrivateKeyInfo");
		//endregion

		//region Get internal properties from parsed schema
		this.version = asn1.result.version.valueBlock.valueDec;
		this.privateKeyAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.privateKeyAlgorithm });
		this.privateKey = asn1.result.privateKey;

		if("attributes" in asn1.result)
			this.attributes = Array.from(asn1.result.attributes, element => new Attribute({ schema: element }));

		switch(this.privateKeyAlgorithm.algorithmId)
		{
			case "1.2.840.113549.1.1.1": // RSA
				{
					const privateKeyASN1 = asn1js.fromBER(this.privateKey.valueBlock.valueHex);
					if(privateKeyASN1.offset !== (-1))
						this.parsedKey = new RSAPrivateKey({ schema: privateKeyASN1.result });
				}
				break;
			case "1.2.840.10045.2.1": // ECDSA
				if("algorithmParams" in this.privateKeyAlgorithm)
				{
					if(this.privateKeyAlgorithm.algorithmParams instanceof asn1js.ObjectIdentifier)
					{
						const privateKeyASN1 = asn1js.fromBER(this.privateKey.valueBlock.valueHex);
						if(privateKeyASN1.offset !== (-1))
						{
							this.parsedKey = new ECPrivateKey({
								namedCurve: this.privateKeyAlgorithm.algorithmParams.valueBlock.toString(),
								schema: privateKeyASN1.result
							});
						}
					}
				}
				break;
			default:
		}
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convert current object to asn1js object and set correct values
	 * @returns {Object} asn1js object
	 */
	toSchema()
	{
		//region Create array for output sequence
		const outputArray = [
			new asn1js.Integer({ value: this.version }),
			this.privateKeyAlgorithm.toSchema(),
			this.privateKey
		];

		if("attributes" in this)
		{
			outputArray.push(new asn1js.Constructed({
				optional: true,
				idBlock: {
					tagClass: 3, // CONTEXT-SPECIFIC
					tagNumber: 0 // [0]
				},
				value: Array.from(this.attributes, 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()
	{
		//region Return common value in case we do not have enough info fo making JWK
		if(("parsedKey" in this) === false)
		{
			const object = {
				version: this.version,
				privateKeyAlgorithm: this.privateKeyAlgorithm.toJSON(),
				privateKey: this.privateKey.toJSON()
			};

			if("attributes" in this)
				object.attributes = Array.from(this.attributes, element => element.toJSON());

			return object;
		}
		//endregion

		//region Making JWK
		const jwk = {};

		switch(this.privateKeyAlgorithm.algorithmId)
		{
			case "1.2.840.10045.2.1": // ECDSA
				jwk.kty = "EC";
				break;
			case "1.2.840.113549.1.1.1": // RSA
				jwk.kty = "RSA";
				break;
			default:
		}

		const publicKeyJWK = this.parsedKey.toJSON();

		for(const key of Object.keys(publicKeyJWK))
			jwk[key] = publicKeyJWK[key];

		return jwk;
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convert JSON value into current object
	 * @param {Object} json
	 */
	fromJSON(json)
	{
		if("kty" in json)
		{
			switch(json.kty.toUpperCase())
			{
				case "EC":
					this.parsedKey = new ECPrivateKey({ json });

					this.privateKeyAlgorithm = new AlgorithmIdentifier({
						algorithmId: "1.2.840.10045.2.1",
						algorithmParams: new asn1js.ObjectIdentifier({ value: this.parsedKey.namedCurve })
					});
					break;
				case "RSA":
					this.parsedKey = new RSAPrivateKey({ json });

					this.privateKeyAlgorithm = new AlgorithmIdentifier({
						algorithmId: "1.2.840.113549.1.1.1",
						algorithmParams: new asn1js.Null()
					});
					break;
				default:
					throw new Error(`Invalid value for "kty" parameter: ${json.kty}`);
			}

			this.privateKey = new asn1js.OctetString({ valueHex: this.parsedKey.toSchema().toBER(false) });
		}
	}
	//**********************************************************************************
}
//**************************************************************************************