bursar

Generate RSA keys in PKCS#1, PKCS#8 or BER format.

Long-form PKCS#1 field names are used for parameter names, not their (rather terse) RSA counterparts.

rsaPrivateKey(options)

• options {Object}
  • modulus {BigInt|Buffer|Uint8Array} RSA n parameter.
  • publicExponent {BigInt|Buffer|Uint8Array} RSA e parameter.
  • privateExponent {BigInt|Buffer|Uint8Array} RSA d parameter.
  • prime1 {BigInt|Buffer|Uint8Array} RSA p parameter.
  • prime2 {BigInt|Buffer|Uint8Array} RSA q parameter.
  • exponent1 {BigInt|Buffer|Uint8Array} RSA dp parameter, d % (p - 1).
  • exponent2 {BigInt|Buffer|Uint8Array} RSA dq parameter, d % (q - 1).
  • coefficient {BigInt|Buffer|Uint8Array} RSA inverseQ parameter, q * inverseQ === 1 % p.
• Returns: {Array} BER-encoded RSA private key.

Keep prime1, prime2 and privateExponent secure at all times; the security of the private key depends on it.

Example:

const {rsaPrivateKey} = require('bursar')
const modulus = 0xBAD5ECn	// insecure; example only
const publicExponent = 0x2n
const privateExponent = 0xBAD5ECn
const prime1 = 0xBAD5ECn
const prime2 = 0xBAD5ECn
const exponent1 = 0xBAD5ECn
const exponent2 = 0xBAD5ECn
const coefficient = 0xBAD5ECn
const options = {modulus, publicExponent, privateExponent, prime1, prime2, exponent1, exponent2, coefficient}
const key = rsaPrivateKey(options)
console.log(key)
// <Buffer 30 30 02 01 00 02 04 00 ba d5 ec 02 01 02 02 04 00 ba d5 ec 02 04 00
// ba d5 ec 02 04 00 ba d5 ec 02 04 00 ba d5 ec 02 04 00 ba d5 ec 02 04 00 ba d5
// ec>

rsaPrivateKey.pkcs1(options)

Like rsaPrivateKey() but the result is returned as a PKCS#1-encoded string.

Example:

const {rsaPrivateKey} = require('bursar')
const modulus = 0xBAD5ECn	// insecure; example only
const publicExponent = 0x2n
const privateExponent = 0xBAD5ECn
const prime1 = 0xBAD5ECn
const prime2 = 0xBAD5ECn
const exponent1 = 0xBAD5ECn
const exponent2 = 0xBAD5ECn
const coefficient = 0xBAD5ECn
const options = {modulus, publicExponent, privateExponent, prime1, prime2, exponent1, exponent2, coefficient}
const key = rsaPrivateKey.pkcs1(options)
console.log(key)
// -----BEGIN RSA PRIVATE KEY-----
// MDACAQACBAC61ewCAQICBAC61ewCBAC61ewCBAC61ewCBAC61ewCBAC61ewCBAC6
// 1ew=
// -----END RSA PRIVATE KEY-----

rsaPrivateKey.pkcs8(options)

Like rsaPrivateKey() but the result is returned as a PKCS#8-encoded string.

Example:

const {rsaPrivateKey} = require('bursar')
const modulus = 0xBAD5ECn	// insecure; example only
const publicExponent = 0x2n
const privateExponent = 0xBAD5ECn
const prime1 = 0xBAD5ECn
const prime2 = 0xBAD5ECn
const exponent1 = 0xBAD5ECn
const exponent2 = 0xBAD5ECn
const coefficient = 0xBAD5ECn
const options = {modulus, publicExponent, privateExponent, prime1, prime2, exponent1, exponent2, coefficient}
const key = rsaPrivateKey.pkcs8(options)
console.log(key)
// -----BEGIN PRIVATE KEY-----
// MEYCAQAwDQYJKoZIhvcNAQEBBQAEMjAwAgEAAgQAutXsAgECAgQAutXsAgQAutXs
// AgQAutXsAgQAutXsAgQAutXsAgQAutXs
// -----END PRIVATE KEY-----

rsaPublicKey(options)

• options {Object}
  • modulus {BigInt|Buffer|Uint8Array} RSA n parameter.
  • publicExponent {BigInt|Buffer|Uint8Array} RSA e parameter.
• Returns: {Array} BER-encoded RSA public key.

Example:

const {rsaPublicKey} = require('bursar')
const modulus = 0xBAD5ECn	// insecure; example only
const publicExponent = 0x2n
const key = rsaPublicKey({modulus, publicExponent})
console.log(Buffer.from(key))
// <Buffer 30 09 02 04 00 b4 d5 ec 02 01 02>

rsaPublicKey.pkcs1(options)

Like rsaPublicKey() but the result is returned as a PKCS#1-encoded string.

Example:

const {rsaPublicKey} = require('bursar')
const modulus = 0xBAD5ECn	// insecure; example only
const publicExponent = 0x2n
const key = rsaPublicKey.pkcs1({modulus, publicExponent})
console.log(key)
// -----BEGIN RSA PUBLIC KEY-----
// MAkCBAC01ewCAQI=
// -----END RSA PUBLIC KEY-----

rsaPublicKey.pkcs8(options)

Like rsaPublicKey() but the result is returned as a PKCS#8-encoded string.

Example:

const {rsaPublicKey} = require('bursar')
const modulus = 0xBAD5ECn	// insecure; example only
const publicExponent = 0x2n
const key = rsaPublicKey.pkcs8({modulus, publicExponent})
console.log(key)
// -----BEGIN PUBLIC KEY-----
// MB0wDQYJKoZIhvcNAQEBBQADDAAwCQIEALTV7AIBAg==
// -----END PUBLIC KEY-----

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changelog

v0.0.3 05/01/2020

• add examples to README

v0.0.2 04/01/2020

• implement missing rsaPrivateKey.pkcs8()

v0.0.1 04/01/2020

• initial release