How to use the node-opcua-crypto.readCertificate function in node-opcua-crypto

encryptBufferWithDerivedKeys,
    makeMessageChunkSignature,
    makeMessageChunkSignatureWithDerivedKeys,
    makeSHA1Thumbprint,
    publicEncrypt_long,
    readCertificate,
    readKeyPem,
    RSA_PKCS1_PADDING
} from "node-opcua-crypto";
import { AsymmetricAlgorithmSecurityHeader, SymmetricAlgorithmSecurityHeader } from "node-opcua-service-secure-channel";
import { SecureMessageChunkManager, SequenceNumberGenerator } from "../source";

// tslint:disable:no-var-requires
const getFixture = require("node-opcua-test-fixtures").getFixture;

const senderCertificate = readCertificate(getFixture("certs/client_cert_1024.pem"));
const senderPrivateKey = readKeyPem(getFixture("certs/client_key_1024.pem"));

const receiverCertificate =  readCertificate(getFixture("certs/server_cert_1024.pem"));
const receiverCertificateThumbprint = makeSHA1Thumbprint(receiverCertificate);

const receiverPublicKey = fs.readFileSync(getFixture("certs/server_public_key_1024.pub", "ascii")).toString();

const sequenceNumberGenerator = new SequenceNumberGenerator();

export type ChunkVisitorFunc = (err: Error | null, chunk?: Buffer) => void;

export function iterateOnSignedMessageChunks(buffer: Buffer, callback: ChunkVisitorFunc) {

    const params = {
        algorithm: "RSA-SHA1",
        privateKey: senderPrivateKey,

makeSHA1Thumbprint,
    publicEncrypt_long,
    readCertificate,
    readKeyPem,
    RSA_PKCS1_PADDING
} from "node-opcua-crypto";
import { AsymmetricAlgorithmSecurityHeader, SymmetricAlgorithmSecurityHeader } from "node-opcua-service-secure-channel";
import { SecureMessageChunkManager, SequenceNumberGenerator } from "../source";

// tslint:disable:no-var-requires
const getFixture = require("node-opcua-test-fixtures").getFixture;

const senderCertificate = readCertificate(getFixture("certs/client_cert_1024.pem"));
const senderPrivateKey = readKeyPem(getFixture("certs/client_key_1024.pem"));

const receiverCertificate =  readCertificate(getFixture("certs/server_cert_1024.pem"));
const receiverCertificateThumbprint = makeSHA1Thumbprint(receiverCertificate);

const receiverPublicKey = fs.readFileSync(getFixture("certs/server_public_key_1024.pub", "ascii")).toString();

const sequenceNumberGenerator = new SequenceNumberGenerator();

export type ChunkVisitorFunc = (err: Error | null, chunk?: Buffer) => void;

export function iterateOnSignedMessageChunks(buffer: Buffer, callback: ChunkVisitorFunc) {

    const params = {
        algorithm: "RSA-SHA1",
        privateKey: senderPrivateKey,
        signatureLength: 128,
    };

const SecureMessageChunkManager = require("../src/secure_message_chunk_manager").SecureMessageChunkManager;
const SequenceNumberGenerator = require("../src/sequence_number_generator").SequenceNumberGenerator;

const AsymmetricAlgorithmSecurityHeader = require("node-opcua-service-secure-channel").AsymmetricAlgorithmSecurityHeader;
const SymmetricAlgorithmSecurityHeader = require("node-opcua-service-secure-channel").SymmetricAlgorithmSecurityHeader;

const crypto_utils = require("node-opcua-crypto");
const fs = require("fs");
const path = require("path");

const getFixture = require("node-opcua-test-fixtures").getFixture;

const senderCertificate = crypto_utils.readCertificate(getFixture("certs/client_cert_1024.pem"));
const senderPrivateKey = crypto_utils.readKeyPem(getFixture("certs/client_key_1024.pem"));

const receiverCertificate = crypto_utils.readCertificate(getFixture("certs/server_cert_1024.pem"));
const receiverCertificateThumbprint = crypto_utils.makeSHA1Thumbprint(receiverCertificate);

const receiverPublicKey = fs.readFileSync(getFixture("certs/server_public_key_1024.pub"));

const sequenceNumberGenerator = new SequenceNumberGenerator();

/**
 * @method iterate_on_signed_message_chunks
 * @param buffer
 * @param callback {Function}
 * @param callback.err  {Error}
 * @param callback.chunks  {Array}
 *
 */
function iterate_on_signed_message_chunks(buffer, callback) {

const hexDump = require("node-opcua-debug").hexDump;

const SecureMessageChunkManager = require("../src/secure_message_chunk_manager").SecureMessageChunkManager;
const SequenceNumberGenerator = require("../src/sequence_number_generator").SequenceNumberGenerator;

const AsymmetricAlgorithmSecurityHeader = require("node-opcua-service-secure-channel").AsymmetricAlgorithmSecurityHeader;
const SymmetricAlgorithmSecurityHeader = require("node-opcua-service-secure-channel").SymmetricAlgorithmSecurityHeader;

const crypto_utils = require("node-opcua-crypto");
const fs = require("fs");
const path = require("path");

const getFixture = require("node-opcua-test-fixtures").getFixture;

const senderCertificate = crypto_utils.readCertificate(getFixture("certs/client_cert_1024.pem"));
const senderPrivateKey = crypto_utils.readKeyPem(getFixture("certs/client_key_1024.pem"));

const receiverCertificate = crypto_utils.readCertificate(getFixture("certs/server_cert_1024.pem"));
const receiverCertificateThumbprint = crypto_utils.makeSHA1Thumbprint(receiverCertificate);

const receiverPublicKey = fs.readFileSync(getFixture("certs/server_public_key_1024.pub"));

const sequenceNumberGenerator = new SequenceNumberGenerator();

/**
 * @method iterate_on_signed_message_chunks
 * @param buffer
 * @param callback {Function}
 * @param callback.err  {Error}
 * @param callback.chunks  {Array}
 *

setTimeout(function () {

                    callback(null, {
                        process: server_exec,
                        pid_collected: pid_collected,
                        endpointUrl: "opc.tcp://" + os.hostname() + ":" + port + "/UA/SampleServer",
                        serverCertificate: crypto_utils.readCertificate(serverCertificateFilename)
                    });

                }, 100);
            }

function _load_certificate(certificateFilename: string): Certificate {
    const der =  readCertificate(certificateFilename);
    return der;
}

function _load_certificate(certificate_file) {
    return crypto_utils.readCertificate(certificate_file);
}
function _load_private_key(private_key_file) {