old-keypairs.js/lib/x509-ec-parser.js

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2018-12-18 07:34:40 +00:00
'use strict';
var Enc = require('./encoding.js');
var x509 = module.exports;
// 1.2.840.10045.3.1.7
// prime256v1 (ANSI X9.62 named elliptic curve)
var OBJ_ID_EC_256 = '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();
x509.parseSec1 = function parseEcOnlyPrivkey(u8, jwk) {
var index = 7;
var len = 32;
var olen = OBJ_ID_EC_256.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_256.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_256.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;