66 lines
1.4 KiB
JavaScript
66 lines
1.4 KiB
JavaScript
var hashUtils = require('./browserHashUtils');
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/**
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* @api private
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*/
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function Hmac(hashCtor, secret) {
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this.hash = new hashCtor();
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this.outer = new hashCtor();
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var inner = bufferFromSecret(hashCtor, secret);
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var outer = new Uint8Array(hashCtor.BLOCK_SIZE);
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outer.set(inner);
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for (var i = 0; i < hashCtor.BLOCK_SIZE; i++) {
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inner[i] ^= 0x36;
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outer[i] ^= 0x5c;
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}
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this.hash.update(inner);
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this.outer.update(outer);
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// Zero out the copied key buffer.
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for (var i = 0; i < inner.byteLength; i++) {
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inner[i] = 0;
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}
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}
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/**
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* @api private
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*/
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module.exports = exports = Hmac;
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Hmac.prototype.update = function (toHash) {
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if (hashUtils.isEmptyData(toHash) || this.error) {
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return this;
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}
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try {
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this.hash.update(hashUtils.convertToBuffer(toHash));
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} catch (e) {
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this.error = e;
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}
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return this;
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};
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Hmac.prototype.digest = function (encoding) {
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if (!this.outer.finished) {
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this.outer.update(this.hash.digest());
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}
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return this.outer.digest(encoding);
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};
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function bufferFromSecret(hashCtor, secret) {
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var input = hashUtils.convertToBuffer(secret);
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if (input.byteLength > hashCtor.BLOCK_SIZE) {
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var bufferHash = new hashCtor;
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bufferHash.update(input);
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input = bufferHash.digest();
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}
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var buffer = new Uint8Array(hashCtor.BLOCK_SIZE);
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buffer.set(input);
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return buffer;
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}
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