rsa-compat.js/lib/rsa.js

// Copyright 2016-2018 AJ ONeal. All rights reserved
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
'use strict';

var RSA = module.exports;
RSA.utils = {};

try {
  require('buffer-v6-polyfill');
} catch(e) {
  /* ignore */
}

var Rasha = require('./rasha');
var RSACSR = require('./rsa-csr');
var NOBJ = {};
var DEFAULT_BITLEN = 2048;
var DEFAULT_EXPONENT = 0x10001;

RSA.generateKeypair = function (options, cb, extra1, extra2) {
  var length;
  var exponent;
  if ('function' === typeof extra2) {
    length = options || DEFAULT_BITLEN;
    exponent = cb || DEFAULT_EXPONENT;
    options = extra1 || NOBJ;
    cb = extra2;
  } else {
    if (!options) { options = NOBJ; }
    length = options.bitlen || DEFAULT_BITLEN;
    exponent = options.exp || DEFAULT_EXPONENT;
  }

  try {
    var keypair = require('./generate-privkey.js')(length, exponent);
    keypair.thumbprint = RSA.thumbprint(keypair);
    cb(null, keypair);
  } catch(e) {
    cb(e);
  }
};

RSA.import = function (options) {
  options = JSON.parse(JSON.stringify(options));

  // Private Keys
  if (options.privateKeyPem) {
    if (!options.privateKeyJwk) {
      options.privateKeyJwk = Rasha.importSync({ pem: options.privateKeyPem });
    }
  }
  if (options.privateKeyJwk) {
    if (!options.privateKeyPem) {
      options.privateKeyPem = Rasha.exportSync({
        jwk: options.privateKeyJwk
      , format: options.format || 'pkcs1'
      , encoding: options.encoding || 'pem'
      });
    }
  }

  // Public Keys
  if (options.publicKeyPem || options.privateKeyPem) {
    if (!options.publicKeyJwk) {
      options.publicKeyJwk = Rasha.importSync({
        pem: options.publicKeyPem || options.privateKeyPem
      , public: true
      });
    }
  }
  if (options.publicKeyJwk || options.privateKeyJwk) {
    if (!options.publicKeyPem) {
      options.publicKeyPem = Rasha.exportSync({
        jwk: options.publicKeyJwk || options.privateKeyJwk
      , format: options.format || 'pkcs1'
      , encoding: options.encoding || 'pem'
      , public: true
      });
    }
  }
  if (!options.publicKeyPem) {
    throw new Error("Error: no keys were present to import");
  }

  // Consistent CRLF
  if (options.privateKeyPem) {
    options.privateKeyPem = options.privateKeyPem
      .trim().replace(/[\r\n]+/g, '\r\n') + '\r\n';
  }
  options.publicKeyPem = options.publicKeyPem
    .trim().replace(/[\r\n]+/g, '\r\n') + '\r\n';

  // Thumbprint
  if (!options.thumbprint) {
    options.thumbprint = RSA._thumbprint(options);
  }

  return options;
};

RSA.exportPrivatePem = function (keypair) {
  keypair = RSA.import(keypair);
  return keypair.privateKeyPem;
};
RSA.exportPublicPem = function (keypair) {
  keypair = RSA.import(keypair);
  return keypair.publicKeyPem;
};

RSA.exportPrivateJwk = function (keypair) {
  keypair = RSA.import(keypair);
  return keypair.privateKeyJwk;
};
RSA.exportPublicJwk = function (keypair) {
  if (!keypair.publicKeyJwk) {
    keypair = RSA.import(keypair);
  }
  return keypair.publicKeyJwk;
};

RSA.signJws = RSA.generateJws = RSA.generateSignatureJws = RSA.generateSignatureJwk =
function (keypair, header, protect, payload) {
// old   (keypair, payload, nonce)
  var nonce;

  keypair = RSA.import(keypair);
  keypair.publicKeyJwk = RSA.exportPublicJwk(keypair);

  if ('string' === typeof protect || ('undefined' === typeof protect && 'undefined' === typeof payload)) {
    console.warn("deprecation notice: new signature for signJws(keypair, header, protect, payload)");
    // old API
    payload = header;
    nonce = protect;
    protect = undefined;
    header = {
      alg: "RS256"
    , jwk: keypair.publicKeyJwk
    };
    protect = { nonce: nonce };
  }

  // Compute JWS signature
  var protectedHeader = "";
  if (protect) {
    protectedHeader = JSON.stringify(protect); // { alg: prot.alg, nonce: prot.nonce, url: prot.url });
  }
  var protected64 = RSA.utils.toWebsafeBase64(Buffer.from(protectedHeader).toString('base64'));
  var payload64 = RSA.utils.toWebsafeBase64(payload.toString('base64'));
  var raw = protected64 + "." + payload64;
  var pem = RSA.exportPrivatePem(keypair);
  var signer = require('crypto').createSign("RSA-SHA256");
  signer.update(raw);

  return {
    header: header
  , protected: protected64
  , payload: payload64
  , signature: signer.sign(pem, 'base64')
    .replace(/\+/g, '-')
    .replace(/\//g, '_')
    .replace(/=/g, '')
  };
};

RSA.generateCsrPem = function (keypair, domains) {
  keypair = RSA.import(keypair);
  return RSACSR.sync({ jwk: keypair.privateKeyJwk, domains: domains });
};
RSA.generateCsrDer = function (keypair, domains) {
  keypair = RSA.import(keypair);
  return RSACSR.sync({
    jwk: keypair.privateKeyJwk
  , domains: domains
  , encoding: 'der'
  });
};
RSA.generateCsrDerWeb64 =RSA.generateCsrWeb64 = function (keypair, names) {
  var buf = RSA.generateCsrDer(keypair, names);
  var b64 = buf.toString('base64');
  return RSA.utils.toWebsafeBase64(b64);
};

RSA._thumbprintInput = function (n, e) {
  // #L147 const rsaThumbprintTemplate = `{"e":"%s","kty":"RSA","n":"%s"}`
  return Buffer.from('{"e":"'+ e + '","kty":"RSA","n":"'+ n +'"}', 'ascii');
};
RSA._thumbprint = function (keypair) {
  var publicKeyJwk = keypair.publicKeyJwk;

  if (!publicKeyJwk.e || !publicKeyJwk.n) {
    throw new Error("You must provide an RSA jwk with 'e' and 'n' (the public components)");
  }

  var input = RSA._thumbprintInput(publicKeyJwk.n, publicKeyJwk.e);
  var base64Digest = require('crypto').createHash('sha256').update(input).digest('base64');

  return RSA.utils.toWebsafeBase64(base64Digest);
};
RSA.thumbprint = function (keypair) {
  if (!keypair.publicKeyJwk) {
    keypair.publicKeyJwk = RSA.exportPublicJwk(keypair);
  }
  return RSA._thumbprint(keypair);
};

RSA.utils.toWebsafeBase64 = function (b64) {
  return b64.replace(/\+/g, "-").replace(/\//g, "_").replace(/=/g,"");
};

RSA.exportPrivateKey = RSA.exportPrivatePem;
RSA.exportPublicKey = RSA.exportPublicPem;