@ldapjs/asn1

What is @ldapjs/asn1?

@ldapjs/asn1 is a Node.js library for encoding and decoding Abstract Syntax Notation One (ASN.1) data structures. ASN.1 is a standard interface description language for defining data structures that can be serialized and deserialized in a cross-platform way. This package is particularly useful for working with LDAP (Lightweight Directory Access Protocol) data, which often uses ASN.1 encoding.

What are @ldapjs/asn1's main functionalities?

Encoding ASN.1 Data

This feature allows you to encode data into ASN.1 format. The code sample demonstrates how to create a BER (Basic Encoding Rules) writer, start a sequence, write an integer, and then end the sequence. The resulting buffer contains the encoded ASN.1 data.

const asn1 = require('@ldapjs/asn1');
const Ber = asn1.Ber;

const writer = new Ber.Writer();
writer.startSequence();
writer.writeInt(42);
writer.endSequence();

const encodedData = writer.buffer;
console.log(encodedData);

Decoding ASN.1 Data

This feature allows you to decode ASN.1 data. The code sample demonstrates how to create a BER reader, read a sequence, and then read an integer from the encoded data. The resulting value is the decoded integer.

const asn1 = require('@ldapjs/asn1');
const Ber = asn1.Ber;

const encodedData = Buffer.from([0x30, 0x03, 0x02, 0x01, 0x2A]);
const reader = new Ber.Reader(encodedData);
reader.readSequence();
const value = reader.readInt();

console.log(value); // 42

Other packages similar to @ldapjs/asn1

asn1.js

asn1.js is a pure JavaScript implementation of ASN.1. It provides a comprehensive set of tools for encoding and decoding ASN.1 data structures. Compared to @ldapjs/asn1, asn1.js offers more flexibility and is widely used in various cryptographic applications.

README

node-asn1 is a library for encoding and decoding ASN.1 datatypes in pure JS. Currently BER encoding is supported; at some point I'll likely have to do DER.

Usage

Mostly, if you're actually needing to read and write ASN.1, you probably don't need this readme to explain what and why. If you have no idea what ASN.1 is, see this: ftp://ftp.rsa.com/pub/pkcs/ascii/layman.asc

The source is pretty much self-explanatory, and has read/write methods for the common types out there.

Decoding

The following reads an ASN.1 sequence with a boolean.

var Ber = require('asn1').Ber;

var reader = new Ber.Reader(Buffer.from([0x30, 0x03, 0x01, 0x01, 0xff]));

reader.readSequence();
console.log('Sequence len: ' + reader.length);
if (reader.peek() === Ber.Boolean)
  console.log(reader.readBoolean());

Encoding

The following generates the same payload as above.

var Ber = require('asn1').Ber;

var writer = new Ber.Writer();

writer.startSequence();
writer.writeBoolean(true);
writer.endSequence();

console.log(writer.buffer);

Installation

npm install asn1

License

MIT.

Bugs

See https://github.com/joyent/node-asn1/issues.