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/*!
* algorithms/ecdsa.js - Elliptic Curve Digitial Signature Algorithms
*
* Copyright (c) 2015 Cisco Systems, Inc. See LICENSE file.
*/
"use strict";
var ecUtil = require("./ec-util.js"),
helpers = require("./helpers.js"),
sha = require("./sha.js");
function idealCurve(hash) {
switch (hash) {
case "SHA-256":
return "P-256";
case "SHA-384":
return "P-384";
case "SHA-512":
return "P-521";
default:
throw new Error("unsupported hash: " + hash);
}
}
function ecdsaSignFN(hash) {
var curve = idealCurve(hash);
// ### Fallback implementation -- uses forge
var fallback = function(key, pdata /*, props */) {
if (curve !== key.crv) {
return Promise.reject(new Error("invalid curve"));
}
var pk = ecUtil.convertToForge(key, false);
var promise;
// generate hash
promise = sha[hash].digest(pdata);
// sign hash
promise = promise.then(function(result) {
result = pk.sign(result);
result = Buffer.concat([result.r, result.s]);
return {
data: pdata,
mac: result
};
});
return promise;
};
// ### WebCrypto API implementation
var webcrypto = function(key, pdata /*, props */) {
if (curve !== key.crv) {
return Promise.reject(new Error("invalid curve"));
}
var pk = ecUtil.convertToJWK(key, false);
var promise;
var alg = {
name: "ECDSA",
namedCurve: pk.crv,
hash: {
name: hash
}
};
promise = helpers.subtleCrypto.importKey("jwk",
pk,
alg,
true,
[ "sign" ]);
promise = promise.then(function(key) {
return helpers.subtleCrypto.sign(alg, key, pdata);
});
promise = promise.then(function(result) {
result = Buffer.from(result);
return {
data: pdata,
mac: result
};
});
return promise;
};
var nodejs;
var nodeHash = hash.toLowerCase().replace("-", "");
if (helpers.nodeCrypto && helpers.nodeCrypto.getHashes().indexOf(nodeHash) > -1) {
nodejs = function(key, pdata) {
if (curve !== key.crv) {
return Promise.reject(new Error("invalid curve"));
}
var promise;
promise = Promise.resolve(helpers.nodeCrypto.createSign(nodeHash));
promise = promise.then(function (sign) {
sign.update(pdata);
return sign;
});
var size;
switch (nodeHash.slice(-3)) {
case "384":
size = 48;
break;
case "512":
size = 66;
break;
default:
size = 32;
}
promise = promise.then(function (sign) {
return ecUtil.derToConcat(sign.sign(ecUtil.convertToPEM(key, true)), size);
});
promise = promise.then(function (result) {
return {
data: pdata,
mac: result
};
});
return promise;
};
}
return helpers.setupFallback(nodejs, webcrypto, fallback);
}
function ecdsaVerifyFN(hash) {
var curve = idealCurve(hash);
// ### Fallback implementation -- uses forge
var fallback = function(key, pdata, mac /*, props */) {
if (curve !== key.crv) {
return Promise.reject(new Error("invalid curve"));
}
var pk = ecUtil.convertToForge(key, true);
var promise;
// generate hash
promise = sha[hash].digest(pdata);
// verify hash
promise = promise.then(function(result) {
var len = mac.length / 2;
var rs = {
r: mac.slice(0, len),
s: mac.slice(len)
};
if (!pk.verify(result, rs)) {
return Promise.reject(new Error("verification failed"));
}
return {
data: pdata,
mac: mac,
valid: true
};
});
return promise;
};
// ### WebCrypto API implementation
var webcrypto = function(key, pdata, mac /* , props */) {
if (curve !== key.crv) {
return Promise.reject(new Error("invalid curve"));
}
var pk = ecUtil.convertToJWK(key, true);
var promise;
var alg = {
name: "ECDSA",
namedCurve: pk.crv,
hash: {
name: hash
}
};
promise = helpers.subtleCrypto.importKey("jwk",
pk,
alg,
true,
["verify"]);
promise = promise.then(function(key) {
return helpers.subtleCrypto.verify(alg, key, mac, pdata);
});
promise = promise.then(function(result) {
if (!result) {
return Promise.reject(new Error("verification failed"));
}
return {
data: pdata,
mac: mac,
valid: true
};
});
return promise;
};
var nodejs;
var nodeHash = hash.toLowerCase().replace("-", "");
if (helpers.nodeCrypto && helpers.nodeCrypto.getHashes().indexOf(nodeHash) > -1) {
nodejs = function(key, pdata, mac /* , props */) {
if (curve !== key.crv) {
return Promise.reject(new Error("invalid curve"));
}
var size;
switch (nodeHash.slice(-3)) {
case "384":
size = 48;
break;
case "512":
size = 66;
break;
default:
size = 32;
}
var promise;
promise = Promise.resolve(helpers.nodeCrypto.createVerify(nodeHash));
promise = promise.then(function (verify) {
verify.update(pdata);
verify.end();
return verify.verify(ecUtil.convertToPEM(key, false), ecUtil.concatToDer(mac, size));
});
promise = promise.then(function (result) {
if (!result) {
throw new Error('verification failed');
}
return {
data: pdata,
mac,
valid: true,
};
});
return promise;
};
}
return helpers.setupFallback(nodejs, webcrypto, fallback);
}
// ### Public API
var ecdsa = {};
// * [name].sign
// * [name].verify
[
"ES256",
"ES384",
"ES512"
].forEach(function(name) {
var hash = name.replace(/ES(\d+)/g, function(m, size) {
return "SHA-" + size;
});
ecdsa[name] = {
sign: ecdsaSignFN(hash),
verify: ecdsaVerifyFN(hash)
};
});
module.exports = ecdsa;