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app_vue/node_modules/node-forge/lib/cipher.js

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+/**
+ * Cipher base API.
+ *
+ * @author Dave Longley
+ *
+ * Copyright (c) 2010-2014 Digital Bazaar, Inc.
+ */
+var forge = require('./forge');
+require('./util');
+
+module.exports = forge.cipher = forge.cipher || {};
+
+// registered algorithms
+forge.cipher.algorithms = forge.cipher.algorithms || {};
+
+/**
+ * Creates a cipher object that can be used to encrypt data using the given
+ * algorithm and key. The algorithm may be provided as a string value for a
+ * previously registered algorithm or it may be given as a cipher algorithm
+ * API object.
+ *
+ * @param algorithm the algorithm to use, either a string or an algorithm API
+ *          object.
+ * @param key the key to use, as a binary-encoded string of bytes or a
+ *          byte buffer.
+ *
+ * @return the cipher.
+ */
+forge.cipher.createCipher = function(algorithm, key) {
+  var api = algorithm;
+  if(typeof api === 'string') {
+    api = forge.cipher.getAlgorithm(api);
+    if(api) {
+      api = api();
+    }
+  }
+  if(!api) {
+    throw new Error('Unsupported algorithm: ' + algorithm);
+  }
+
+  // assume block cipher
+  return new forge.cipher.BlockCipher({
+    algorithm: api,
+    key: key,
+    decrypt: false
+  });
+};
+
+/**
+ * Creates a decipher object that can be used to decrypt data using the given
+ * algorithm and key. The algorithm may be provided as a string value for a
+ * previously registered algorithm or it may be given as a cipher algorithm
+ * API object.
+ *
+ * @param algorithm the algorithm to use, either a string or an algorithm API
+ *          object.
+ * @param key the key to use, as a binary-encoded string of bytes or a
+ *          byte buffer.
+ *
+ * @return the cipher.
+ */
+forge.cipher.createDecipher = function(algorithm, key) {
+  var api = algorithm;
+  if(typeof api === 'string') {
+    api = forge.cipher.getAlgorithm(api);
+    if(api) {
+      api = api();
+    }
+  }
+  if(!api) {
+    throw new Error('Unsupported algorithm: ' + algorithm);
+  }
+
+  // assume block cipher
+  return new forge.cipher.BlockCipher({
+    algorithm: api,
+    key: key,
+    decrypt: true
+  });
+};
+
+/**
+ * Registers an algorithm by name. If the name was already registered, the
+ * algorithm API object will be overwritten.
+ *
+ * @param name the name of the algorithm.
+ * @param algorithm the algorithm API object.
+ */
+forge.cipher.registerAlgorithm = function(name, algorithm) {
+  name = name.toUpperCase();
+  forge.cipher.algorithms[name] = algorithm;
+};
+
+/**
+ * Gets a registered algorithm by name.
+ *
+ * @param name the name of the algorithm.
+ *
+ * @return the algorithm, if found, null if not.
+ */
+forge.cipher.getAlgorithm = function(name) {
+  name = name.toUpperCase();
+  if(name in forge.cipher.algorithms) {
+    return forge.cipher.algorithms[name];
+  }
+  return null;
+};
+
+var BlockCipher = forge.cipher.BlockCipher = function(options) {
+  this.algorithm = options.algorithm;
+  this.mode = this.algorithm.mode;
+  this.blockSize = this.mode.blockSize;
+  this._finish = false;
+  this._input = null;
+  this.output = null;
+  this._op = options.decrypt ? this.mode.decrypt : this.mode.encrypt;
+  this._decrypt = options.decrypt;
+  this.algorithm.initialize(options);
+};
+
+/**
+ * Starts or restarts the encryption or decryption process, whichever
+ * was previously configured.
+ *
+ * For non-GCM mode, the IV may be a binary-encoded string of bytes, an array
+ * of bytes, a byte buffer, or an array of 32-bit integers. If the IV is in
+ * bytes, then it must be Nb (16) bytes in length. If the IV is given in as
+ * 32-bit integers, then it must be 4 integers long.
+ *
+ * Note: an IV is not required or used in ECB mode.
+ *
+ * For GCM-mode, the IV must be given as a binary-encoded string of bytes or
+ * a byte buffer. The number of bytes should be 12 (96 bits) as recommended
+ * by NIST SP-800-38D but another length may be given.
+ *
+ * @param options the options to use:
+ *          iv the initialization vector to use as a binary-encoded string of
+ *            bytes, null to reuse the last ciphered block from a previous
+ *            update() (this "residue" method is for legacy support only).
+ *          additionalData additional authentication data as a binary-encoded
+ *            string of bytes, for 'GCM' mode, (default: none).
+ *          tagLength desired length of authentication tag, in bits, for
+ *            'GCM' mode (0-128, default: 128).
+ *          tag the authentication tag to check if decrypting, as a
+ *             binary-encoded string of bytes.
+ *          output the output the buffer to write to, null to create one.
+ */
+BlockCipher.prototype.start = function(options) {
+  options = options || {};
+  var opts = {};
+  for(var key in options) {
+    opts[key] = options[key];
+  }
+  opts.decrypt = this._decrypt;
+  this._finish = false;
+  this._input = forge.util.createBuffer();
+  this.output = options.output || forge.util.createBuffer();
+  this.mode.start(opts);
+};
+
+/**
+ * Updates the next block according to the cipher mode.
+ *
+ * @param input the buffer to read from.
+ */
+BlockCipher.prototype.update = function(input) {
+  if(input) {
+    // input given, so empty it into the input buffer
+    this._input.putBuffer(input);
+  }
+
+  // do cipher operation until it needs more input and not finished
+  while(!this._op.call(this.mode, this._input, this.output, this._finish) &&
+    !this._finish) {}
+
+  // free consumed memory from input buffer
+  this._input.compact();
+};
+
+/**
+ * Finishes encrypting or decrypting.
+ *
+ * @param pad a padding function to use in CBC mode, null for default,
+ *          signature(blockSize, buffer, decrypt).
+ *
+ * @return true if successful, false on error.
+ */
+BlockCipher.prototype.finish = function(pad) {
+  // backwards-compatibility w/deprecated padding API
+  // Note: will overwrite padding functions even after another start() call
+  if(pad && (this.mode.name === 'ECB' || this.mode.name === 'CBC')) {
+    this.mode.pad = function(input) {
+      return pad(this.blockSize, input, false);
+    };
+    this.mode.unpad = function(output) {
+      return pad(this.blockSize, output, true);
+    };
+  }
+
+  // build options for padding and afterFinish functions
+  var options = {};
+  options.decrypt = this._decrypt;
+
+  // get # of bytes that won't fill a block
+  options.overflow = this._input.length() % this.blockSize;
+
+  if(!this._decrypt && this.mode.pad) {
+    if(!this.mode.pad(this._input, options)) {
+      return false;
+    }
+  }
+
+  // do final update
+  this._finish = true;
+  this.update();
+
+  if(this._decrypt && this.mode.unpad) {
+    if(!this.mode.unpad(this.output, options)) {
+      return false;
+    }
+  }
+
+  if(this.mode.afterFinish) {
+    if(!this.mode.afterFinish(this.output, options)) {
+      return false;
+    }
+  }
+
+  return true;
+};