src/PublicKeyInfo.js

import * as asn1js from "asn1js";
import { getParametersValue, clearProps } from "pvutils";
import { getCrypto } from "./common.js";
import AlgorithmIdentifier from "./AlgorithmIdentifier.js";
import ECPublicKey from "./ECPublicKey.js";
import RSAPublicKey from "./RSAPublicKey.js";
//**************************************************************************************
/**
 * Class from RFC5280
 */
export default class PublicKeyInfo 
{
	//**********************************************************************************
	/**
	 * Constructor for PublicKeyInfo class
	 * @param {Object} [parameters={}]
	 * @property {Object} [schema] asn1js parsed value
	 */
	constructor(parameters = {})
	{
		//region Internal properties of the object
		/**
		 * @type {AlgorithmIdentifier}
		 * @description Algorithm identifier
		 */
		this.algorithm = getParametersValue(parameters, "algorithm", PublicKeyInfo.defaultValues("algorithm"));
		/**
		 * @type {BitString}
		 * @description Subject public key value
		 */
		this.subjectPublicKey = getParametersValue(parameters, "subjectPublicKey", PublicKeyInfo.defaultValues("subjectPublicKey"));
		
		if("parsedKey" in parameters)
			/**
			 * @type {ECPublicKey|RSAPublicKey}
			 * @description Parsed public key value
			 */
			this.parsedKey = getParametersValue(parameters, "parsedKey", PublicKeyInfo.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 "algorithm":
				return new AlgorithmIdentifier();
			case "subjectPublicKey":
				return new asn1js.BitString();
			default:
				throw new Error(`Invalid member name for PublicKeyInfo 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 = {})
	{
		//SubjectPublicKeyInfo  ::=  Sequence  {
		//    algorithm            AlgorithmIdentifier,
		//    subjectPublicKey     BIT STRING  }
		
		/**
		 * @type {Object}
		 * @property {string} [blockName]
		 * @property {string} [algorithm]
		 * @property {string} [subjectPublicKey]
		 */
		const names = getParametersValue(parameters, "names", {});
		
		return (new asn1js.Sequence({
			name: (names.blockName || ""),
			value: [
				AlgorithmIdentifier.schema(names.algorithm || {}),
				new asn1js.BitString({ name: (names.subjectPublicKey || "") })
			]
		}));
	}
	//**********************************************************************************
	/**
	 * Convert parsed asn1js object into current class
	 * @param {!Object} schema
	 */
	fromSchema(schema)
	{
		//region Clear input data first
		clearProps(schema, [
			"algorithm",
			"subjectPublicKey"
		]);
		//endregion
		
		//region Check the schema is valid
		const asn1 = asn1js.compareSchema(schema,
			schema,
			PublicKeyInfo.schema({
				names: {
					algorithm: {
						names: {
							blockName: "algorithm"
						}
					},
					subjectPublicKey: "subjectPublicKey"
				}
			})
		);
		
		if(asn1.verified === false)
			throw new Error("Object's schema was not verified against input data for PublicKeyInfo");
		//endregion
		
		//region Get internal properties from parsed schema
		this.algorithm = new AlgorithmIdentifier({ schema: asn1.result.algorithm });
		this.subjectPublicKey = asn1.result.subjectPublicKey;
		
		switch(this.algorithm.algorithmId)
		{
			case "1.2.840.10045.2.1": // ECDSA
				if("algorithmParams" in this.algorithm)
				{
					if(this.algorithm.algorithmParams instanceof asn1js.ObjectIdentifier)
					{
						try
						{
							this.parsedKey = new ECPublicKey({
								namedCurve: this.algorithm.algorithmParams.valueBlock.toString(),
								schema: this.subjectPublicKey.valueBlock.valueHex
							});
						}
						catch(ex){} // Could be a problems during recognision of internal public key data here. Let's ignore them.
					}
				}
				break;
			case "1.2.840.113549.1.1.1": // RSA
				{
					const publicKeyASN1 = asn1js.fromBER(this.subjectPublicKey.valueBlock.valueHex);
					if(publicKeyASN1.offset !== (-1))
					{
						try
						{
							this.parsedKey = new RSAPublicKey({ schema: publicKeyASN1.result });
						}
						catch(ex){} // Could be a problems during recognision of internal public key data here. Let's ignore them.
					}
				}
				break;
			default:
		}
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convert current object to asn1js object and set correct values
	 * @returns {Object} asn1js object
	 */
	toSchema()
	{
		//region Construct and return new ASN.1 schema for this object
		return (new asn1js.Sequence({
			value: [
				this.algorithm.toSchema(),
				this.subjectPublicKey
			]
		}));
		//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)
		{
			return {
				algorithm: this.algorithm.toJSON(),
				subjectPublicKey: this.subjectPublicKey.toJSON()
			};
		}
		//endregion
		
		//region Making JWK
		const jwk = {};
		
		switch(this.algorithm.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 ECPublicKey({ json });
					
					this.algorithm = new AlgorithmIdentifier({
						algorithmId: "1.2.840.10045.2.1",
						algorithmParams: new asn1js.ObjectIdentifier({ value: this.parsedKey.namedCurve })
					});
					break;
				case "RSA":
					this.parsedKey = new RSAPublicKey({ json });
					
					this.algorithm = 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.subjectPublicKey = new asn1js.BitString({ valueHex: this.parsedKey.toSchema().toBER(false) });
		}
	}
	//**********************************************************************************
	importKey(publicKey)
	{
		//region Initial variables
		let sequence = Promise.resolve();
		const _this = this;
		//endregion
		
		//region Initial check
		if(typeof publicKey === "undefined")
			return Promise.reject("Need to provide publicKey input parameter");
		//endregion
		
		//region Get a "crypto" extension
		const crypto = getCrypto();
		if(typeof crypto === "undefined")
			return Promise.reject("Unable to create WebCrypto object");
		//endregion
		
		//region Export public key
		sequence = sequence.then(() =>
			crypto.exportKey("spki", publicKey));
		//endregion
		
		//region Initialize internal variables by parsing exported value
		sequence = sequence.then(
			/**
			 * @param {ArrayBuffer} exportedKey
			 */
			exportedKey =>
			{
				const asn1 = asn1js.fromBER(exportedKey);
				try
				{
					_this.fromSchema(asn1.result);
				}
				catch(exception)
				{
					return Promise.reject("Error during initializing object from schema");
				}
				
				return undefined;
			},
			error => Promise.reject(`Error during exporting public key: ${error}`)
		);
		//endregion
		
		return sequence;
	}
	//**********************************************************************************
}
//**************************************************************************************