bintzwing/core/convenience.js
2011-12-03 15:39:11 -08:00

271 lines
8.8 KiB
JavaScript

/** @fileOverview Convenince functions centered around JSON encapsulation.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** @namespace JSON encapsulation */
sjcl.json = {
/** Default values for encryption */
defaults: { v:1, iter:1000, ks:128, ts:64, mode:"ccm", adata:"", cipher:"aes" },
/** Simple encryption function.
* @param {String|bitArray} password The password or key.
* @param {String} plaintext The data to encrypt.
* @param {Object} [params] The parameters including tag, iv and salt.
* @param {Object} [rp] A returned version with filled-in parameters.
* @return {String} The ciphertext.
* @throws {sjcl.exception.invalid} if a parameter is invalid.
*/
encrypt: function (password, plaintext, params, rp) {
params = params || {};
rp = rp || {};
var j = sjcl.json, p = j._add({ iv: sjcl.random.randomWords(4,0) },
j.defaults), tmp, prp;
j._add(p, params);
if (typeof p.salt === "string") {
p.salt = sjcl.codec.base64.toBits(p.salt);
}
if (typeof p.iv === "string") {
p.iv = sjcl.codec.base64.toBits(p.iv);
}
if (!sjcl.mode[p.mode] ||
!sjcl.cipher[p.cipher] ||
(typeof password === "string" && p.iter <= 100) ||
(p.ts !== 64 && p.ts !== 96 && p.ts !== 128) ||
(p.ks !== 128 && p.ks !== 192 && p.ks !== 256) ||
(p.iv.length < 2 || p.iv.length > 4)) {
throw new sjcl.exception.invalid("json encrypt: invalid parameters");
}
if (typeof password === "string") {
tmp = sjcl.misc.cachedPbkdf2(password, p);
password = tmp.key.slice(0,p.ks/32);
p.salt = tmp.salt;
}
if (typeof plaintext === "string") {
plaintext = sjcl.codec.utf8String.toBits(plaintext);
}
prp = new sjcl.cipher[p.cipher](password);
/* return the json data */
j._add(rp, p);
rp.key = password;
/* do the encryption */
p.ct = sjcl.mode[p.mode].encrypt(prp, plaintext, p.iv, p.adata, p.ts);
return j.encode(j._subtract(p, j.defaults));
},
/** Simple decryption function.
* @param {String|bitArray} password The password or key.
* @param {String} ciphertext The ciphertext to decrypt.
* @param {Object} [params] Additional non-default parameters.
* @param {Object} [rp] A returned object with filled parameters.
* @return {String} The plaintext.
* @throws {sjcl.exception.invalid} if a parameter is invalid.
* @throws {sjcl.exception.corrupt} if the ciphertext is corrupt.
*/
decrypt: function (password, ciphertext, params, rp) {
params = params || {};
rp = rp || {};
var j = sjcl.json, p = j._add(j._add(j._add({},j.defaults),j.decode(ciphertext)), params, true), ct, tmp, prp;
if (typeof p.salt === "string") {
p.salt = sjcl.codec.base64.toBits(p.salt);
}
if (typeof p.iv === "string") {
p.iv = sjcl.codec.base64.toBits(p.iv);
}
if (!sjcl.mode[p.mode] ||
!sjcl.cipher[p.cipher] ||
(typeof password === "string" && p.iter <= 100) ||
(p.ts !== 64 && p.ts !== 96 && p.ts !== 128) ||
(p.ks !== 128 && p.ks !== 192 && p.ks !== 256) ||
(!p.iv) ||
(p.iv.length < 2 || p.iv.length > 4)) {
throw new sjcl.exception.invalid("json decrypt: invalid parameters");
}
if (typeof password === "string") {
tmp = sjcl.misc.cachedPbkdf2(password, p);
password = tmp.key.slice(0,p.ks/32);
p.salt = tmp.salt;
}
prp = new sjcl.cipher[p.cipher](password);
/* do the decryption */
ct = sjcl.mode[p.mode].decrypt(prp, p.ct, p.iv, p.adata, p.ts);
/* return the json data */
j._add(rp, p);
rp.key = password;
return sjcl.codec.utf8String.fromBits(ct);
},
/** Encode a flat structure into a JSON string.
* @param {Object} obj The structure to encode.
* @return {String} A JSON string.
* @throws {sjcl.exception.invalid} if obj has a non-alphanumeric property.
* @throws {sjcl.exception.bug} if a parameter has an unsupported type.
*/
encode: function (obj) {
var i, out='{', comma='';
for (i in obj) {
if (obj.hasOwnProperty(i)) {
if (!i.match(/^[a-z0-9]+$/i)) {
throw new sjcl.exception.invalid("json encode: invalid property name");
}
out += comma + '"' + i + '"' + ':';
comma = ',';
switch (typeof obj[i]) {
case 'number':
case 'boolean':
out += obj[i];
break;
case 'string':
out += '"' + escape(obj[i]) + '"';
break;
case 'object':
out += '"' + sjcl.codec.base64.fromBits(obj[i],1) + '"';
break;
default:
throw new sjcl.exception.bug("json encode: unsupported type");
}
}
}
return out+'}';
},
/** Decode a simple (flat) JSON string into a structure. The ciphertext,
* adata, salt and iv will be base64-decoded.
* @param {String} str The string.
* @return {Object} The decoded structure.
* @throws {sjcl.exception.invalid} if str isn't (simple) JSON.
*/
decode: function (str) {
str = str.replace(/\s/g,'');
if (!str.match(/^\{.*\}$/)) {
throw new sjcl.exception.invalid("json decode: this isn't json!");
}
var a = str.replace(/^\{|\}$/g, '').split(/,/), out={}, i, m;
for (i=0; i<a.length; i++) {
if (!(m=a[i].match(/^(?:(["']?)([a-z][a-z0-9]*)\1):(?:(\d+)|"([a-z0-9+\/%*_.@=\-]*)")$/i))) {
throw new sjcl.exception.invalid("json decode: this isn't json!");
}
if (m[3]) {
out[m[2]] = parseInt(m[3],10);
} else {
out[m[2]] = m[2].match(/^(ct|salt|iv)$/) ? sjcl.codec.base64.toBits(m[4]) : unescape(m[4]);
}
}
return out;
},
/** Insert all elements of src into target, modifying and returning target.
* @param {Object} target The object to be modified.
* @param {Object} src The object to pull data from.
* @param {boolean} [requireSame=false] If true, throw an exception if any field of target differs from corresponding field of src.
* @return {Object} target.
* @private
*/
_add: function (target, src, requireSame) {
if (target === undefined) { target = {}; }
if (src === undefined) { return target; }
var i;
for (i in src) {
if (src.hasOwnProperty(i)) {
if (requireSame && target[i] !== undefined && target[i] !== src[i]) {
throw new sjcl.exception.invalid("required parameter overridden");
}
target[i] = src[i];
}
}
return target;
},
/** Remove all elements of minus from plus. Does not modify plus.
* @private
*/
_subtract: function (plus, minus) {
var out = {}, i;
for (i in plus) {
if (plus.hasOwnProperty(i) && plus[i] !== minus[i]) {
out[i] = plus[i];
}
}
return out;
},
/** Return only the specified elements of src.
* @private
*/
_filter: function (src, filter) {
var out = {}, i;
for (i=0; i<filter.length; i++) {
if (src[filter[i]] !== undefined) {
out[filter[i]] = src[filter[i]];
}
}
return out;
}
};
/** Simple encryption function; convenient shorthand for sjcl.json.encrypt.
* @param {String|bitArray} password The password or key.
* @param {String} plaintext The data to encrypt.
* @param {Object} [params] The parameters including tag, iv and salt.
* @param {Object} [rp] A returned version with filled-in parameters.
* @return {String} The ciphertext.
*/
sjcl.encrypt = sjcl.json.encrypt;
/** Simple decryption function; convenient shorthand for sjcl.json.decrypt.
* @param {String|bitArray} password The password or key.
* @param {String} ciphertext The ciphertext to decrypt.
* @param {Object} [params] Additional non-default parameters.
* @param {Object} [rp] A returned object with filled parameters.
* @return {String} The plaintext.
*/
sjcl.decrypt = sjcl.json.decrypt;
/** The cache for cachedPbkdf2.
* @private
*/
sjcl.misc._pbkdf2Cache = {};
/** Cached PBKDF2 key derivation.
* @param {String} The password.
* @param {Object} The derivation params (iteration count and optional salt).
* @return {Object} The derived data in key, the salt in salt.
*/
sjcl.misc.cachedPbkdf2 = function (password, obj) {
var cache = sjcl.misc._pbkdf2Cache, c, cp, str, salt, iter;
obj = obj || {};
iter = obj.iter || 1000;
/* open the cache for this password and iteration count */
cp = cache[password] = cache[password] || {};
c = cp[iter] = cp[iter] || { firstSalt: (obj.salt && obj.salt.length) ?
obj.salt.slice(0) : sjcl.random.randomWords(2,0) };
salt = (obj.salt === undefined) ? c.firstSalt : obj.salt;
c[salt] = c[salt] || sjcl.misc.pbkdf2(password, salt, obj.iter);
return { key: c[salt].slice(0), salt:salt.slice(0) };
};