55 lines
1.5 KiB
JavaScript
55 lines
1.5 KiB
JavaScript
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/** @fileOverview Password-based key-derivation function, version 2.0.
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*
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* @author Emily Stark
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* @author Mike Hamburg
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* @author Dan Boneh
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*/
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/** Password-Based Key-Derivation Function, version 2.0.
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*
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* Generate keys from passwords using PBKDF2-HMAC-SHA256.
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*
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* This is the method specified by RSA's PKCS #5 standard.
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*
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* @param {bitArray|String} password The password.
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* @param {bitArray} salt The salt. Should have lots of entropy.
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* @param {Number} [count=1000] The number of iterations. Higher numbers make the function slower but more secure.
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* @param {Number} [length] The length of the derived key. Defaults to the
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output size of the hash function.
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* @param {Object} [Prff=sjcl.misc.hmac] The pseudorandom function family.
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* @return {bitArray} the derived key.
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*/
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sjcl.misc.pbkdf2 = function (password, salt, count, length, Prff) {
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count = count || 1000;
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if (length < 0 || count < 0) {
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throw sjcl.exception.invalid("invalid params to pbkdf2");
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}
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if (typeof password === "string") {
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password = sjcl.codec.utf8String.toBits(password);
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}
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Prff = Prff || sjcl.misc.hmac;
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var prf = new Prff(password),
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u, ui, i, j, k, out = [], b = sjcl.bitArray;
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for (k = 1; 32 * out.length < (length || 1); k++) {
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u = ui = prf.encrypt(b.concat(salt,[k]));
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for (i=1; i<count; i++) {
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ui = prf.encrypt(ui);
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for (j=0; j<ui.length; j++) {
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u[j] ^= ui[j];
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}
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}
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out = out.concat(u);
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}
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if (length) { out = b.clamp(out, length); }
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return out;
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};
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