292 lines
8.4 KiB
Markdown
292 lines
8.4 KiB
Markdown
# [rsa-compat.js](https://git.coolaj86.com/coolaj86/rsa-compat.js)
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| A [Root](https://therootcompany.com) Project.
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JavaScript RSA utils that work on Windows, Mac, and Linux with or without C compiler
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This was built for the [ACME.js](https://git.coolaj86.com/coolaj86/acme.js) and
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[Greenlock.js](https://git.coolaj86.com/coolaj86/greenlock.js) **Let's Encrypt** clients
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and is particularly suitable for building **certbot**-like clients.
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(if you're looking for similar tools in the browser, consider [Bluecrypt](https://www.npmjs.com/search?q=bluecrypt))
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# Install
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node.js
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```bash
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npm install --save rsa-compat
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```
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If you need compatibility with older versions of node, you may need to `npm install --save ursa-optional node-forge`.
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### CLI
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```bash
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npm install --global rsa-compat
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```
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# Usage
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CLI
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---
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You can generate keypairs on Windows, Mac, and Linux using rsa-keygen-js:
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```bash
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# generates a new keypair in the current directory
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rsa-keypiar-js
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```
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Examples
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--------
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Generate an RSA Keypair:
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```javascript
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var RSA = require('rsa-compat').RSA;
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var options = { bitlen: 2048, exp: 65537, public: true, pem: true, internal: true };
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RSA.generateKeypair(options, function (err, keypair) {
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console.log(keypair);
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});
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```
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Here's what the object might look like:
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`console.log(keypair)`:
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```javascript
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{ publicKeyPem: '-----BEGIN RSA PUBLIC KEY-----\n/*base64 pem-encoded string*/'
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, privateKeyPem: '-----BEGIN RSA PRIVATE KEY-----\n/*base64 pem-encoded string*/'
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, privateKeyJwk: {
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kty: "RSA"
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, n: '/*base64 modulus n = pq*/'
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, e: '/*base64 exponent (usually 65537)*/'
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, d: '/*base64 private exponent (d = e^−1 (mod ϕ(n))/'
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, p: '/*base64 first prime*/'
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, q: '/*base64 second prime*/'
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, dp: '/*base64 first exponent for Chinese remainder theorem (dP = d (mod p−1))*/'
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, dq: '/*base64 Second exponent, used for CRT (dQ = d (mod q−1))/'
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, qi: '/*base64 Coefficient, used for CRT (qinv = q^−1 (mod p))*/'
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}
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, publicKeyJwk: {
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kty: "RSA"
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, n: '/*base64 modulus n = pq*/'
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, e: '/*base64 exponent (usually 65537)*/'
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}
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}
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```
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See http://crypto.stackexchange.com/questions/6593/what-data-is-saved-in-rsa-private-key to learn a little more about the meaning of the specific fields in the JWK.
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# API Summary
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* `RSA.generateKeypair(options, cb)`
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* (deprecated `RSA.generateKeypair(bitlen, exp, options, cb)`)
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* `RSA.import(options)`
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* (deprecated `RSA.import(keypair, options)`)
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* `RSA.exportPrivatePem(keypair)`
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* `RSA.exportPublicPem(keypair)`
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* `RSA.exportPrivateJwk(keypair)`
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* `RSA.exportPublicJwk(keypair)`
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* `RSA.signJws(keypair, header, protect, payload)`
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* (deprecated `RSA.signJws(keypair, payload, nonce)`)
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* `RSA.generateCsrPem(keypair, names)`
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* `RSA.generateCsrDerWeb64(keypair, names)`
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* `RSA.thumbprint(keypair)`
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`keypair` can be any object with any of these keys `publicKeyPem, privateKeyPem, publicKeyJwk, privateKeyJwk`
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### RSA.generateKeypair(options, cb)
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Create a private keypair and export it as PEM, JWK, and/or internal formats
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```javascript
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RSA.generateKeypair(null, function (keypair) { /*...*/ });
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RSA.generateKeypair({
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bitlen: 2048, exp: 65537, pem: false, public: false, internal: false
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}, function (keypair) { /*...*/ });
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```
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`options`:
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```javascript
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{ public: false // export public keys
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, pem: false // export pems
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, jwk: true // export jwks
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, internal: false // preserve internal intermediate formats (_ursa, _forge)
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, thumbprint: false // JWK sha256 thumbprint
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, fingerprint: false // NOT IMPLEMENTED (RSA key fingerprint)
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}
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```
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### RSA.import(options)
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Imports keypair as JWKs and internal values `_ursa` and `_forge`.
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```javascript
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var keypair = RSA.import({ type: 'RSA', privateKeyPem: '...' });
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console.log(keypair);
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```
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```javascript
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{ privateKeyPem: ..., privateKeyJwk: ..., _ursa: ..., _forge: ... }
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```
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### RSA.export*(keypair)
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You put in an object like `{ privateKeyPem: '...' }` or `{ publicKeyJwk: {} }`
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and you get back the keys in the format you requested.
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Note:
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* Private keys **can** be used to export both private and public keys
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* Public keys can **NOT** be used to generate private keys
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Example:
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```javascript
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var keypair = { privateKeyPem: '...' };
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keypair.publicKeyJwk = RSA.exportPublicJwk(keypair);
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console.log(keypair);
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```
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### RSA.signJws(keypair, payload, nonce)
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Generates a signature in JWS format (necessary for **certbot**/**letsencrypt**).
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```javascript
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var message = "Hello, World!"
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var nonce = crypto.randomBytes(16).toString('hex');
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var jws = RSA.signJws(keypair, message, nonce);
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console.log(jws);
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```
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The result looks like this:
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```javascript
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{ "header": {
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"alg": "RS256",
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"jwk": {
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"kty": "RSA",
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"n": "AMJubTfOtAarnJytLE8fhNsEI8wnpjRvBXGK/Kp0675J10ORzxyMLqzIZF3tcrUkKBrtdc79u4X0GocDUgukpfkY+2UPUS/GxehUYbYrJYWOLkoJWzxn7wfoo9X1JgvBMY6wHQnTKvnzZdkom2FMhGxkLaEUGDSfsNznTTZNBBg9",
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"e": "AQAB"
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}
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},
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"protected": "eyJub25jZSI6IjhlZjU2MjRmNWVjOWQzZWYifQ",
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"payload": "JLzF1NBNCV3kfbJ5sFaFyX94fJuL2H-IzaoBN-ciiHk",
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"signature": "Wb2al5SDyh5gjmkV79MK9m3sfNBBPjntSKor-34BBoGwr6n8qEnBmqB1Y4zbo-5rmvsoPmJsnRlP_hRiUY86zSAQyfbisTGrGBl0IQ7ditpkfYVm0rBWJ8WnYNqYNp8K3qcD7NW72tsy-XoWEjNlz4lWJeRdEG2Nt4CJgnREH4Y"
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}
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```
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### RSA.thumbprint(keypair)
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Generates a JWK thumbprint.
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`RSA.thumbprint(keypair)`:
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```javascript
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var thumb = RSA.thumbprint(keypair);
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console.log(thumb);
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```
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```
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// kK4OXp5CT1FEkHi6WkegldmeTJecSTyJN-DxZ91nQ30
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```
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### RSA.generateCsr*(keypair, names)
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You can generate the CSR in human-readable or binary / base64 formats:
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`RSA.generateCsrPem(keypair, names)`:
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```javascript
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var pem = RSA.generateCsrPem(keypair, [ 'example.com', 'www.example.com' ]);
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console.log(pem);
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```
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web-safe base64 for **certbot**/**letsencrypt**:
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`RSA.generateCsrDerWeb64(keypair, names)`:
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```javascript
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var web64 = RSA.generateCsrDerWeb64(keypair, [ 'example.com', 'www.example.com' ]);
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console.log(web64);
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```
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# Old Node Versions
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In recent versions of node >= v10.12 native RSA key generation is fairly quick for 2048-bit keys
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(though it may still be too slow for some applications with 4096-bit keys).
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In old versions, however, and especially on ARM and/or MIPS procesors, RSA key generation can be
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very, very slow.
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In old node versions `ursa` can provide faster key generation, but it must be compiled.
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`ursa` will not compile for new node versions, but they already include the same openssl bindings anyawy.
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```bash
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npm install --save ursa
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```
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Also, if you need **Node < v6** support:
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```bash
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npm install --save buffer-v6-polyfill
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```
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## Security and Compatibility
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**TL;DR**: Use the default values 2048 and 65537 unless you have a really, really good reason to do otherwise.
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Various platforms *require* these values.
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Most security experts agree that 4096-bit is no more "secure" than 2048-bit -
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a fundamental vulnerability in the RSA algorithm which causes 2048 to be broken
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will most likely also cause 4096 to be broken
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(i.e. if someone can prove mathematically prove P=NP or a way to predict prime numbers).
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Also, many platforms
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only support 2048 bit keys due to the insecurity of 1024-bit keys (which are not 1/2 secure
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but rather 1/(2^1028) less secure) and the excess computational
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cost of 4096-bit keys (it's not a 2x increase, it's more like a 2^2048 increase).
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As to why 65537 is even optional as a prime exponent or why it matters... no idea,
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but it does matter.
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# ChangeLog:
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* v2.0.0
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* remove ursa and node-forge as strict dependencies
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* v1.9.0
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* consistently handle key generation across node crypto, ursa, and forge
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* move all other operations to rasha.js and rsa-csr.js
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* bugfix non-standard JWKs output (which *mostly* worked)
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* v1.4.0
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* remove ursa as dependency (just causes confusion), but note in docs
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* drop node < v6 support
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# Legal
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rsa-compat.js directly includes code from
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[Rasha.js](https://git.coolaj86.com/coolaj86/rasha.js)
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and
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[RSA-CSR.js](https://git.coolaj86.com/coolaj86/rsa-csr.js)
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(also [Root](https://therootcompany.com) projects),
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retrofitted for rsa-compat.
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[rsa-compat.js](https://git.coolaj86.com/coolaj86/rsa-compat.js) |
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MPL-2.0 |
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[Terms of Use](https://therootcompany.com/legal/#terms) |
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[Privacy Policy](https://therootcompany.com/legal/#privacy)
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