src/RSASSAPSSParams.js

import * as asn1js from "asn1js";
import { getParametersValue, clearProps } from "pvutils";
import AlgorithmIdentifier from "./AlgorithmIdentifier.js";
//**************************************************************************************
/**
 * Class from RFC4055
 */
export default class RSASSAPSSParams
{
	//**********************************************************************************
	/**
	 * Constructor for RSASSAPSSParams class
	 * @param {Object} [parameters={}]
	 * @property {Object} [schema] asn1js parsed value
	 */
	constructor(parameters = {})
	{
		//region Internal properties of the object
		/**
		 * @type {AlgorithmIdentifier}
		 * @description Algorithms of hashing (DEFAULT sha1)
		 */
		this.hashAlgorithm = getParametersValue(parameters, "hashAlgorithm", RSASSAPSSParams.defaultValues("hashAlgorithm"));
		/**
		 * @type {AlgorithmIdentifier}
		 * @description Algorithm of "mask generaion function (MGF)" (DEFAULT mgf1SHA1)
		 */
		this.maskGenAlgorithm = getParametersValue(parameters, "maskGenAlgorithm", RSASSAPSSParams.defaultValues("maskGenAlgorithm"));
		/**
		 * @type {number}
		 * @description Salt length (DEFAULT 20)
		 */
		this.saltLength = getParametersValue(parameters, "saltLength", RSASSAPSSParams.defaultValues("saltLength"));
		/**
		 * @type {number}
		 * @description (DEFAULT 1)
		 */
		this.trailerField = getParametersValue(parameters, "trailerField", RSASSAPSSParams.defaultValues("trailerField"));
		//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 "hashAlgorithm":
				return new AlgorithmIdentifier({
					algorithmId: "1.3.14.3.2.26", // SHA-1
					algorithmParams: new asn1js.Null()
				});
			case "maskGenAlgorithm":
				return new AlgorithmIdentifier({
					algorithmId: "1.2.840.113549.1.1.8", // MGF1
					algorithmParams: (new AlgorithmIdentifier({
						algorithmId: "1.3.14.3.2.26", // SHA-1
						algorithmParams: new asn1js.Null()
					})).toSchema()
				});
			case "saltLength":
				return 20;
			case "trailerField":
				return 1;
			default:
				throw new Error(`Invalid member name for RSASSAPSSParams 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 = {})
	{
		//RSASSA-PSS-params  ::=  Sequence  {
		//    hashAlgorithm      [0] HashAlgorithm DEFAULT sha1Identifier,
		//    maskGenAlgorithm   [1] MaskGenAlgorithm DEFAULT mgf1SHA1Identifier,
		//    saltLength         [2] Integer DEFAULT 20,
		//    trailerField       [3] Integer DEFAULT 1  }

		/**
		 * @type {Object}
		 * @property {string} [blockName]
		 * @property {string} [hashAlgorithm]
		 * @property {string} [maskGenAlgorithm]
		 * @property {string} [saltLength]
		 * @property {string} [trailerField]
		 */
		const names = getParametersValue(parameters, "names", {});

		return (new asn1js.Sequence({
			name: (names.blockName || ""),
			value: [
				new asn1js.Constructed({
					idBlock: {
						tagClass: 3, // CONTEXT-SPECIFIC
						tagNumber: 0 // [0]
					},
					optional: true,
					value: [AlgorithmIdentifier.schema(names.hashAlgorithm || {})]
				}),
				new asn1js.Constructed({
					idBlock: {
						tagClass: 3, // CONTEXT-SPECIFIC
						tagNumber: 1 // [1]
					},
					optional: true,
					value: [AlgorithmIdentifier.schema(names.maskGenAlgorithm || {})]
				}),
				new asn1js.Constructed({
					idBlock: {
						tagClass: 3, // CONTEXT-SPECIFIC
						tagNumber: 2 // [2]
					},
					optional: true,
					value: [new asn1js.Integer({ name: (names.saltLength || "") })]
				}),
				new asn1js.Constructed({
					idBlock: {
						tagClass: 3, // CONTEXT-SPECIFIC
						tagNumber: 3 // [3]
					},
					optional: true,
					value: [new asn1js.Integer({ name: (names.trailerField || "") })]
				})
			]
		}));
	}
	//**********************************************************************************
	/**
	 * Convert parsed asn1js object into current class
	 * @param {!Object} schema
	 */
	fromSchema(schema)
	{
		//region Clear input data first
		clearProps(schema, [
			"hashAlgorithm",
			"maskGenAlgorithm",
			"saltLength",
			"trailerField"
		]);
		//endregion
		
		//region Check the schema is valid
		const asn1 = asn1js.compareSchema(schema,
			schema,
			RSASSAPSSParams.schema({
				names: {
					hashAlgorithm: {
						names: {
							blockName: "hashAlgorithm"
						}
					},
					maskGenAlgorithm: {
						names: {
							blockName: "maskGenAlgorithm"
						}
					},
					saltLength: "saltLength",
					trailerField: "trailerField"
				}
			})
		);

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

		//region Get internal properties from parsed schema
		if("hashAlgorithm" in asn1.result)
			this.hashAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.hashAlgorithm });

		if("maskGenAlgorithm" in asn1.result)
			this.maskGenAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.maskGenAlgorithm });

		if("saltLength" in asn1.result)
			this.saltLength = asn1.result.saltLength.valueBlock.valueDec;

		if("trailerField" in asn1.result)
			this.trailerField = asn1.result.trailerField.valueBlock.valueDec;
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convert current object to asn1js object and set correct values
	 * @returns {Object} asn1js object
	 */
	toSchema()
	{
		//region Create array for output sequence
		const outputArray = [];
		
		if(!this.hashAlgorithm.isEqual(RSASSAPSSParams.defaultValues("hashAlgorithm")))
		{
			outputArray.push(new asn1js.Constructed({
				idBlock: {
					tagClass: 3, // CONTEXT-SPECIFIC
					tagNumber: 0 // [0]
				},
				value: [this.hashAlgorithm.toSchema()]
			}));
		}
		
		if(!this.maskGenAlgorithm.isEqual(RSASSAPSSParams.defaultValues("maskGenAlgorithm")))
		{
			outputArray.push(new asn1js.Constructed({
				idBlock: {
					tagClass: 3, // CONTEXT-SPECIFIC
					tagNumber: 1 // [1]
				},
				value: [this.maskGenAlgorithm.toSchema()]
			}));
		}
		
		if(this.saltLength !== RSASSAPSSParams.defaultValues("saltLength"))
		{
			outputArray.push(new asn1js.Constructed({
				idBlock: {
					tagClass: 3, // CONTEXT-SPECIFIC
					tagNumber: 2 // [2]
				},
				value: [new asn1js.Integer({ value: this.saltLength })]
			}));
		}
		
		if(this.trailerField !== RSASSAPSSParams.defaultValues("trailerField"))
		{
			outputArray.push(new asn1js.Constructed({
				idBlock: {
					tagClass: 3, // CONTEXT-SPECIFIC
					tagNumber: 3 // [3]
				},
				value: [new asn1js.Integer({ value: this.trailerField })]
			}));
		}
		//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 = {};

		if(!this.hashAlgorithm.isEqual(RSASSAPSSParams.defaultValues("hashAlgorithm")))
			object.hashAlgorithm = this.hashAlgorithm.toJSON();

		if(!this.maskGenAlgorithm.isEqual(RSASSAPSSParams.defaultValues("maskGenAlgorithm")))
			object.maskGenAlgorithm = this.maskGenAlgorithm.toJSON();

		if(this.saltLength !== RSASSAPSSParams.defaultValues("saltLength"))
			object.saltLength = this.saltLength;

		if(this.trailerField !== RSASSAPSSParams.defaultValues("trailerField"))
			object.trailerField = this.trailerField;

		return object;
	}
	//**********************************************************************************
}
//**************************************************************************************