bluecrypt-keypairs.js/lib/x509.js

'use strict';
(function (exports) {
  'use strict';
  var x509 = exports.x509 = {}; 
  var ASN1 = exports.ASN1;
  var Enc = exports.Enc;

  // 1.2.840.10045.3.1.7
  // prime256v1 (ANSI X9.62 named elliptic curve)
  var OBJ_ID_EC = '06 08 2A8648CE3D030107'.replace(/\s+/g, '').toLowerCase();
  // 1.3.132.0.34
  // secp384r1 (SECG (Certicom) named elliptic curve)
  var OBJ_ID_EC_384 = '06 05 2B81040022'.replace(/\s+/g, '').toLowerCase();
  // 1.2.840.10045.2.1
  // ecPublicKey (ANSI X9.62 public key type)
  var OBJ_ID_EC_PUB = '06 07 2A8648CE3D0201'.replace(/\s+/g, '').toLowerCase();

  x509.parseSec1 = function parseEcOnlyPrivkey(u8, jwk) {
    var index = 7;
    var len = 32;
    var olen = OBJ_ID_EC.length / 2;

    if ("P-384" === jwk.crv) {
      olen = OBJ_ID_EC_384.length / 2;
      index = 8;
      len = 48;
    }
    if (len !== u8[index - 1]) {
      throw new Error("Unexpected bitlength " + len);
    }

    // private part is d
    var d = u8.slice(index, index + len);
    // compression bit index
    var ci = index + len + 2 + olen + 2 + 3;
    var c = u8[ci];
    var x, y;

    if (0x04 === c) {
      y = u8.slice(ci + 1 + len, ci + 1 + len + len);
    } else if (0x02 !== c) {
      throw new Error("not a supported EC private key");
    }
    x = u8.slice(ci + 1, ci + 1 + len);

    return {
      kty: jwk.kty
      , crv: jwk.crv
      , d: Enc.bufToUrlBase64(d)
      //, dh: Enc.bufToHex(d)
      , x: Enc.bufToUrlBase64(x)
      //, xh: Enc.bufToHex(x)
      , y: Enc.bufToUrlBase64(y)
      //, yh: Enc.bufToHex(y)
    };
  };

  x509.parsePkcs8 = function parseEcPkcs8(u8, jwk) {
    var index = 24 + (OBJ_ID_EC.length / 2);
    var len = 32;
    if ("P-384" === jwk.crv) {
      index = 24 + (OBJ_ID_EC_384.length / 2) + 2;
      len = 48;
    }

    //console.log(index, u8.slice(index));
    if (0x04 !== u8[index]) {
      //console.log(jwk);
      throw new Error("privkey not found");
    }
    var d = u8.slice(index + 2, index + 2 + len);
    var ci = index + 2 + len + 5;
    var xi = ci + 1;
    var x = u8.slice(xi, xi + len);
    var yi = xi + len;
    var y;
    if (0x04 === u8[ci]) {
      y = u8.slice(yi, yi + len);
    } else if (0x02 !== u8[ci]) {
      throw new Error("invalid compression bit (expected 0x04 or 0x02)");
    }

    return {
      kty: jwk.kty
      , crv: jwk.crv
      , d: Enc.bufToUrlBase64(d)
      //, dh: Enc.bufToHex(d)
      , x: Enc.bufToUrlBase64(x)
      //, xh: Enc.bufToHex(x)
      , y: Enc.bufToUrlBase64(y)
      //, yh: Enc.bufToHex(y)
    };
  };

  x509.parseSpki = function parsePem(u8, jwk) {
    var ci = 16 + OBJ_ID_EC.length / 2;
    var len = 32;

    if ("P-384" === jwk.crv) {
      ci = 16 + OBJ_ID_EC_384.length / 2;
      len = 48;
    }

    var c = u8[ci];
    var xi = ci + 1;
    var x = u8.slice(xi, xi + len);
    var yi = xi + len;
    var y;
    if (0x04 === c) {
      y = u8.slice(yi, yi + len);
    } else if (0x02 !== c) {
      throw new Error("not a supported EC private key");
    }

    return {
      kty: jwk.kty
      , crv: jwk.crv
      , x: Enc.bufToUrlBase64(x)
      //, xh: Enc.bufToHex(x)
      , y: Enc.bufToUrlBase64(y)
      //, yh: Enc.bufToHex(y)
    };
  };
  x509.parsePkix = x509.parseSpki;

  x509.packSec1 = function (jwk) {
    var d = Enc.base64ToHex(jwk.d);
    var x = Enc.base64ToHex(jwk.x);
    var y = Enc.base64ToHex(jwk.y);
    var objId = ('P-256' === jwk.crv) ? OBJ_ID_EC : OBJ_ID_EC_384;
    return Enc.hexToBuf(
      ASN1('30'
        , ASN1.UInt('01')
        , ASN1('04', d)
        , ASN1('A0', objId)
        , ASN1('A1', ASN1.BitStr('04' + x + y)))
    );
  };
  /**
   * take a private jwk and creates a der from it
   * @param {*} jwk 
   */
  x509.packPkcs8 = function (jwk) {
    var d = Enc.base64ToHex(jwk.d);
    var x = Enc.base64ToHex(jwk.x);
    var y = Enc.base64ToHex(jwk.y);
    var objId = ('P-256' === jwk.crv) ? OBJ_ID_EC : OBJ_ID_EC_384;
    return Enc.hexToBuf(
      ASN1('30'
        , ASN1.UInt('00')
        , ASN1('30'
          , OBJ_ID_EC_PUB
          , objId
        )
        , ASN1('04'
          , ASN1('30'
            , ASN1.UInt('01')
            , ASN1('04', d)
            , ASN1('A1', ASN1.BitStr('04' + x + y)))))
    );
  };
  x509.packSpki = function (jwk) {
    var x = Enc.base64ToHex(jwk.x);
    var y = Enc.base64ToHex(jwk.y);
    var objId = ('P-256' === jwk.crv) ? OBJ_ID_EC : OBJ_ID_EC_384;
    return Enc.hexToBuf(
      ASN1('30'
        , ASN1('30'
          , OBJ_ID_EC_PUB
          , objId
        )
        , ASN1.BitStr('04' + x + y))
    );
  };
  x509.packPkix = x509.packSpki;

}('undefined' !== typeof module ? module.exports : window));