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Refactor some low-level crypto things

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This commit is contained in:
Matt Corallo 2014-05-09 03:43:23 -04:00
parent 905357a2e1
commit 5583e82a20
4 changed files with 42 additions and 53 deletions
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59
js/crypto.js
View file

@ -1,30 +1,3 @@
function HmacSHA256(key, input) {
input = assertIsArrayBuffer(input);
key = assertIsArrayBuffer(key);
return window.crypto.subtle.sign({name: "HMAC", hash: "SHA-256"}, key, input);
}
function encryptAESCTR(input, key, counter) {
input = assertIsArrayBuffer(input);
key = assertIsArrayBuffer(key);
counter = assertIsArrayBuffer(counter);
return window.crypto.subtle.encrypt({name: "AES-CTR", counter: counter}, key, input);
}
function decryptAESCTR(input, key, counter) {
input = assertIsArrayBuffer(input);
key = assertIsArrayBuffer(key);
counter = assertIsArrayBuffer(counter);
return window.crypto.subtle.decrypt({name: "AES-CTR", counter: counter}, key, input);
}
function decryptAESCBC(input, key, iv) {
input = assertIsArrayBuffer(input);
key = assertIsArrayBuffer(key);
iv = assertIsArrayBuffer(iv);
return window.crypto.subtle.decrypt({name: "AES-CBC", iv: iv}, key, input);
}
// functions exposed for replacement and direct calling in test code
var crypto_tests = {};
@ -42,6 +15,11 @@ window.crypto = (function() {
}
}
function HmacSHA256(key, input) {
return window.crypto.subtle.sign({name: "HMAC", hash: "SHA-256"}, key, input);
}
crypto_tests.privToPub = function(privKey, isIdentity) {
if (privKey.byteLength != 32)
throw new Error("Invalid private key");
@ -168,11 +146,11 @@ window.crypto = (function() {
crypto_tests.HKDF = function(input, salt, info) {
// Specific implementation of RFC 5869 that only returns exactly 64 bytes
return HmacSHA256(salt, input).then(function(PRK) {
return HmacSHA256(salt, toArrayBuffer(input)).then(function(PRK) {
var infoString = getString(info);
// TextSecure implements a slightly tweaked version of RFC 5869: the 0 and 1 should be 1 and 2 here
return HmacSHA256(PRK, infoString + String.fromCharCode(0)).then(function(T1) {
return HmacSHA256(PRK, getString(T1) + infoString + String.fromCharCode(1)).then(function(T2) {
return HmacSHA256(PRK, toArrayBuffer(infoString + String.fromCharCode(0))).then(function(T1) {
return HmacSHA256(PRK, toArrayBuffer(getString(T1) + infoString + String.fromCharCode(1))).then(function(T2) {
return [ T1, T2 ];
});
});
@ -200,7 +178,7 @@ window.crypto = (function() {
if (version === undefined)
version = 1;
return HmacSHA256(key, String.fromCharCode(version) + getString(data)).then(function(calculated_mac) {
return HmacSHA256(key, toArrayBuffer(String.fromCharCode(version) + getString(data))).then(function(calculated_mac) {
var macString = getString(mac);
if (calculated_mac.substring(0, macString.length) != macString)
@ -212,7 +190,7 @@ window.crypto = (function() {
if (version === undefined)
version = 1;
return HmacSHA256(key, String.fromCharCode(version) + getString(data));
return HmacSHA256(key, toArrayBuffer(String.fromCharCode(version) + getString(data)));
}
/******************************
@ -294,8 +272,9 @@ window.crypto = (function() {
return new Promise(function(resolve) { resolve() }); // Stalker, much?
if (chain.chainKey.counter < counter) {
return HmacSHA256(chain.chainKey.key, String.fromCharCode(1)).then(function(mac) {
return HmacSHA256(chain.chainKey.key, String.fromCharCode(2)).then(function(key) {
var key = toArrayBuffer(chain.chainKey.key);
return HmacSHA256(key, toArrayBuffer(String.fromCharCode(1))).then(function(mac) {
return HmacSHA256(key, toArrayBuffer(String.fromCharCode(2))).then(function(key) {
chain.messageKeys[chain.chainKey.counter + 1] = mac;
chain.chainKey.key = key
chain.chainKey.counter += 1;
@ -367,8 +346,10 @@ window.crypto = (function() {
delete chain.messageKeys[message.counter];
verifyMACWithVersionByte(messageProto, keys[1], mac, (2 << 4) | 2);
var iv = getString(intToArrayBuffer(message.counter));
return decryptAESCTR(message.ciphertext, keys[0], iv).then(function(plaintext) {
var counter = intToArrayBuffer(message.counter);
return window.crypto.subtle.decrypt({name: "AES-CTR", counter: counter}, keys[0], toArrayBuffer(message.ciphertext))
.then(function(plaintext) {
//TODO: removeOldChains(session);
delete session['pendingPreKey'];
@ -399,7 +380,7 @@ window.crypto = (function() {
var mac = decodedMessage.subarray(decodedMessage.length - 10, decodedMessage.length);
return verifyMACWithVersionByte(ivAndCipherText, mac_key, mac).then(function() {
return decryptAESCBC(ciphertext, aes_key, iv);
return window.crypto.subtle.decrypt({name: "AES-CBC", iv: iv}, aes_key, ciphertext);
});
};
@ -440,8 +421,8 @@ window.crypto = (function() {
msg.counter = chain.chainKey.counter;
msg.previousCounter = session.currentRatchet.previousCounter;
var iv = intToArrayBuffer(chain.chainKey.counter);
return encryptAESCTR(plaintext, keys[0], iv).then(function(ciphertext) {
var counter = intToArrayBuffer(chain.chainKey.counter);
return window.crypto.subtle.encrypt({name: "AES-CTR", counter: counter}, keys[0], plaintext).then(function(ciphertext) {
msg.ciphertext = ciphertext;
var encodedMsg = getString(msg.encode());

6
js/helpers.js
View file

@ -159,12 +159,6 @@ function toArrayBuffer(thing) {
return res;
}
function assertIsArrayBuffer(thing) {
if (thing !== Object(thing) || thing.__proto__ != StaticArrayBufferProto)
console.log("WARNING: Needed a ArrayBuffer");
return toArrayBuffer(thing);
}
function ensureStringed(thing) {
if (getStringable(thing))
return getString(thing);

9
js/test.js
View file

@ -304,7 +304,6 @@ registerOnLoadFunction(function() {
var doStep;
var stepDone = function(res) {
console.log('stepDone');
if (!res || privKeyQueue.length != 0) {
crypto_tests.createNewKeyPair = origCreateNewKeyPair;
return false;
@ -444,7 +443,7 @@ console.log('stepDone');
var key = hexToArrayBuffer('6f35628d65813435534b5d67fbdb54cb33403d04e843103e6399f806cb5df95febbdd61236f33245');
var input = hexToArrayBuffer('752cff52e4b90768558e5369e75d97c69643509a5e5904e0a386cbe4d0970ef73f918f675945a9aefe26daea27587e8dc909dd56fd0468805f834039b345f855cfe19c44b55af241fff3ffcd8045cd5c288e6c4e284c3720570b58e4d47b8feeedc52fd1401f698a209fccfa3b4c0d9a797b046a2759f82a54c41ccd7b5f592b');
var mac = getString(hexToArrayBuffer('05d1243e6465ed9620c9aec1c351a186'));
return HmacSHA256(key, input).then(function(result) {
return window.crypto.subtle.sign({name: "HMAC", hash: "SHA-256"}, key, input).then(function(result) {
return getString(result).substring(0, mac.length) === mac;
});
}, "HMAC SHA-256", false);
@ -454,7 +453,7 @@ console.log('stepDone');
var counter = hexToArrayBuffer('f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff');
var plaintext = hexToArrayBuffer('6bc1bee22e409f96e93d7e117393172a');
var ciphertext = hexToArrayBuffer('874d6191b620e3261bef6864990db6ce');
return encryptAESCTR(plaintext, key, counter).then(function(result) {
return window.crypto.subtle.encrypt({name: "AES-CTR", counter: counter}, key, plaintext).then(function(result) {
return getString(result) === getString(ciphertext);
});
}, "Encrypt AES-CTR", false);
@ -464,7 +463,7 @@ console.log('stepDone');
var counter = hexToArrayBuffer('f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff');
var plaintext = hexToArrayBuffer('6bc1bee22e409f96e93d7e117393172a');
var ciphertext = hexToArrayBuffer('874d6191b620e3261bef6864990db6ce');
return decryptAESCTR(ciphertext, key, counter).then(function(result) {
return window.crypto.subtle.decrypt({name: "AES-CTR", counter: counter}, key, ciphertext).then(function(result) {
return getString(result) === getString(plaintext);
});
}, "Decrypt AES-CTR", false);
@ -474,7 +473,7 @@ console.log('stepDone');
var iv = hexToArrayBuffer('000102030405060708090a0b0c0d0e0f');
var plaintext = hexToArrayBuffer('6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710');
var ciphertext = hexToArrayBuffer('f58c4c04d6e5f1ba779eabfb5f7bfbd69cfc4e967edb808d679f777bc6702c7d39f23369a9d9bacfa530e26304231461b2eb05e2c39be9fcda6c19078c6a9d1b3f461796d6b0d6b2e0c2a72b4d80e644');
return decryptAESCBC(ciphertext, key, iv).then(function(result) {
return window.crypto.subtle.decrypt({name: "AES-CBC", iv: iv}, key, ciphertext).then(function(result) {
return getString(result) === getString(plaintext);
});
}, "Decrypt AES-CBC", false);

21
js/webcrypto.js
View file

@ -4,8 +4,16 @@ window.crypto.subtle = (function() {
if (window.crypto.subtle !== undefined && window.crypto.subtle !== null) {
return window.crypto.subtle;
} else {
var StaticArrayBufferProto = new ArrayBuffer().__proto__;
function assertIsArrayBuffer(thing) {
if (thing !== Object(thing) || thing.__proto__ != StaticArrayBufferProto)
throw new Error("WARNING: Needed a ArrayBuffer");
}
// private implementation functions
function HmacSHA256(key, input) {
assertIsArrayBuffer(key);
assertIsArrayBuffer(input);
return CryptoJS.HmacSHA256(
CryptoJS.lib.WordArray.create(toArrayBuffer(input)),
CryptoJS.enc.Latin1.parse(getString(key))
@ -13,6 +21,9 @@ window.crypto.subtle = (function() {
};
function encryptAESCTR(plaintext, key, counter) {
assertIsArrayBuffer(plaintext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(counter);
return CryptoJS.AES.encrypt(CryptoJS.enc.Latin1.parse(getString(plaintext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{mode: CryptoJS.mode.CTR, iv: CryptoJS.enc.Latin1.parse(getString(counter)),
@ -21,6 +32,9 @@ window.crypto.subtle = (function() {
};
function decryptAESCTR(ciphertext, key, counter) {
assertIsArrayBuffer(ciphertext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(counter);
return CryptoJS.AES.decrypt(btoa(getString(ciphertext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{mode: CryptoJS.mode.CTR, iv: CryptoJS.enc.Latin1.parse(getString(counter)),
@ -29,6 +43,9 @@ window.crypto.subtle = (function() {
};
function decryptAESCBC(ciphertext, key, iv) {
assertIsArrayBuffer(ciphertext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(iv);
return CryptoJS.AES.decrypt(btoa(getString(ciphertext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{iv: CryptoJS.enc.Latin1.parse(getString(iv))})
@ -40,9 +57,7 @@ window.crypto.subtle = (function() {
function promise(implementation) {
var args = Array.prototype.slice.call(arguments);
args.shift();
return new Promise(function(resolve) {
resolve(toArrayBuffer(implementation.apply(this, args)));
});
return new Promise.resolve(toArrayBuffer(implementation.apply(this, args)));
}
// public interface functions