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-/**
- * Advanced Encryption Standard (AES) implementation.
- *
- * This implementation is based on the public domain library 'jscrypto' which
- * was written by:
- *
- * Emily Stark (estark@stanford.edu)
- * Mike Hamburg (mhamburg@stanford.edu)
- * Dan Boneh (dabo@cs.stanford.edu)
- *
- * Parts of this code are based on the OpenSSL implementation of AES:
- * http://www.openssl.org
- *
- * @author Dave Longley
- *
- * Copyright (c) 2010-2014 Digital Bazaar, Inc.
- */
-(function() {
-/* ########## Begin module implementation ########## */
-function initModule(forge) {
-
-/* AES API */
-forge.aes = forge.aes || {};
-
-/**
- * Deprecated. Instead, use:
- *
- * var cipher = forge.cipher.createCipher('AES-<mode>', key);
- * cipher.start({iv: iv});
- *
- * Creates an AES cipher object to encrypt data using the given symmetric key.
- * The output will be stored in the 'output' member of the returned cipher.
- *
- * The key and iv may be given as a string of bytes, an array of bytes,
- * a byte buffer, or an array of 32-bit words.
- *
- * @param key the symmetric key to use.
- * @param iv the initialization vector to use.
- * @param output the buffer to write to, null to create one.
- * @param mode the cipher mode to use (default: 'CBC').
- *
- * @return the cipher.
- */
-forge.aes.startEncrypting = function(key, iv, output, mode) {
- var cipher = _createCipher({
- key: key,
- output: output,
- decrypt: false,
- mode: mode
- });
- cipher.start(iv);
- return cipher;
-};
-
-/**
- * Deprecated. Instead, use:
- *
- * var cipher = forge.cipher.createCipher('AES-<mode>', key);
- *
- * Creates an AES cipher object to encrypt data using the given symmetric key.
- *
- * The key may be given as a string of bytes, an array of bytes, a
- * byte buffer, or an array of 32-bit words.
- *
- * @param key the symmetric key to use.
- * @param mode the cipher mode to use (default: 'CBC').
- *
- * @return the cipher.
- */
-forge.aes.createEncryptionCipher = function(key, mode) {
- return _createCipher({
- key: key,
- output: null,
- decrypt: false,
- mode: mode
- });
-};
-
-/**
- * Deprecated. Instead, use:
- *
- * var decipher = forge.cipher.createDecipher('AES-<mode>', key);
- * decipher.start({iv: iv});
- *
- * Creates an AES cipher object to decrypt data using the given symmetric key.
- * The output will be stored in the 'output' member of the returned cipher.
- *
- * The key and iv may be given as a string of bytes, an array of bytes,
- * a byte buffer, or an array of 32-bit words.
- *
- * @param key the symmetric key to use.
- * @param iv the initialization vector to use.
- * @param output the buffer to write to, null to create one.
- * @param mode the cipher mode to use (default: 'CBC').
- *
- * @return the cipher.
- */
-forge.aes.startDecrypting = function(key, iv, output, mode) {
- var cipher = _createCipher({
- key: key,
- output: output,
- decrypt: true,
- mode: mode
- });
- cipher.start(iv);
- return cipher;
-};
-
-/**
- * Deprecated. Instead, use:
- *
- * var decipher = forge.cipher.createDecipher('AES-<mode>', key);
- *
- * Creates an AES cipher object to decrypt data using the given symmetric key.
- *
- * The key may be given as a string of bytes, an array of bytes, a
- * byte buffer, or an array of 32-bit words.
- *
- * @param key the symmetric key to use.
- * @param mode the cipher mode to use (default: 'CBC').
- *
- * @return the cipher.
- */
-forge.aes.createDecryptionCipher = function(key, mode) {
- return _createCipher({
- key: key,
- output: null,
- decrypt: true,
- mode: mode
- });
-};
-
-/**
- * Creates a new AES cipher algorithm object.
- *
- * @param name the name of the algorithm.
- * @param mode the mode factory function.
- *
- * @return the AES algorithm object.
- */
-forge.aes.Algorithm = function(name, mode) {
- if(!init) {
- initialize();
- }
- var self = this;
- self.name = name;
- self.mode = new mode({
- blockSize: 16,
- cipher: {
- encrypt: function(inBlock, outBlock) {
- return _updateBlock(self._w, inBlock, outBlock, false);
- },
- decrypt: function(inBlock, outBlock) {
- return _updateBlock(self._w, inBlock, outBlock, true);
- }
- }
- });
- self._init = false;
-};
-
-/**
- * Initializes this AES algorithm by expanding its key.
- *
- * @param options the options to use.
- * key the key to use with this algorithm.
- * decrypt true if the algorithm should be initialized for decryption,
- * false for encryption.
- */
-forge.aes.Algorithm.prototype.initialize = function(options) {
- if(this._init) {
- return;
- }
-
- var key = options.key;
- var tmp;
-
- /* Note: The key may be a string of bytes, an array of bytes, a byte
- buffer, or an array of 32-bit integers. If the key is in bytes, then
- it must be 16, 24, or 32 bytes in length. If it is in 32-bit
- integers, it must be 4, 6, or 8 integers long. */
-
- if(typeof key === 'string' &&
- (key.length === 16 || key.length === 24 || key.length === 32)) {
- // convert key string into byte buffer
- key = forge.util.createBuffer(key);
- } else if(forge.util.isArray(key) &&
- (key.length === 16 || key.length === 24 || key.length === 32)) {
- // convert key integer array into byte buffer
- tmp = key;
- key = forge.util.createBuffer();
- for(var i = 0; i < tmp.length; ++i) {
- key.putByte(tmp[i]);
- }
- }
-
- // convert key byte buffer into 32-bit integer array
- if(!forge.util.isArray(key)) {
- tmp = key;
- key = [];
-
- // key lengths of 16, 24, 32 bytes allowed
- var len = tmp.length();
- if(len === 16 || len === 24 || len === 32) {
- len = len >>> 2;
- for(var i = 0; i < len; ++i) {
- key.push(tmp.getInt32());
- }
- }
- }
-
- // key must be an array of 32-bit integers by now
- if(!forge.util.isArray(key) ||
- !(key.length === 4 || key.length === 6 || key.length === 8)) {
- throw new Error('Invalid key parameter.');
- }
-
- // encryption operation is always used for these modes
- var mode = this.mode.name;
- var encryptOp = (['CFB', 'OFB', 'CTR', 'GCM'].indexOf(mode) !== -1);
-
- // do key expansion
- this._w = _expandKey(key, options.decrypt && !encryptOp);
- this._init = true;
-};
-
-/**
- * Expands a key. Typically only used for testing.
- *
- * @param key the symmetric key to expand, as an array of 32-bit words.
- * @param decrypt true to expand for decryption, false for encryption.
- *
- * @return the expanded key.
- */
-forge.aes._expandKey = function(key, decrypt) {
- if(!init) {
- initialize();
- }
- return _expandKey(key, decrypt);
-};
-
-/**
- * Updates a single block. Typically only used for testing.
- *
- * @param w the expanded key to use.
- * @param input an array of block-size 32-bit words.
- * @param output an array of block-size 32-bit words.
- * @param decrypt true to decrypt, false to encrypt.
- */
-forge.aes._updateBlock = _updateBlock;
-
-
-/** Register AES algorithms **/
-
-registerAlgorithm('AES-ECB', forge.cipher.modes.ecb);
-registerAlgorithm('AES-CBC', forge.cipher.modes.cbc);
-registerAlgorithm('AES-CFB', forge.cipher.modes.cfb);
-registerAlgorithm('AES-OFB', forge.cipher.modes.ofb);
-registerAlgorithm('AES-CTR', forge.cipher.modes.ctr);
-registerAlgorithm('AES-GCM', forge.cipher.modes.gcm);
-
-function registerAlgorithm(name, mode) {
- var factory = function() {
- return new forge.aes.Algorithm(name, mode);
- };
- forge.cipher.registerAlgorithm(name, factory);
-}
-
-
-/** AES implementation **/
-
-var init = false; // not yet initialized
-var Nb = 4; // number of words comprising the state (AES = 4)
-var sbox; // non-linear substitution table used in key expansion
-var isbox; // inversion of sbox
-var rcon; // round constant word array
-var mix; // mix-columns table
-var imix; // inverse mix-columns table
-
-/**
- * Performs initialization, ie: precomputes tables to optimize for speed.
- *
- * One way to understand how AES works is to imagine that 'addition' and
- * 'multiplication' are interfaces that require certain mathematical
- * properties to hold true (ie: they are associative) but they might have
- * different implementations and produce different kinds of results ...
- * provided that their mathematical properties remain true. AES defines
- * its own methods of addition and multiplication but keeps some important
- * properties the same, ie: associativity and distributivity. The
- * explanation below tries to shed some light on how AES defines addition
- * and multiplication of bytes and 32-bit words in order to perform its
- * encryption and decryption algorithms.
- *
- * The basics:
- *
- * The AES algorithm views bytes as binary representations of polynomials
- * that have either 1 or 0 as the coefficients. It defines the addition
- * or subtraction of two bytes as the XOR operation. It also defines the
- * multiplication of two bytes as a finite field referred to as GF(2^8)
- * (Note: 'GF' means "Galois Field" which is a field that contains a finite
- * number of elements so GF(2^8) has 256 elements).
- *
- * This means that any two bytes can be represented as binary polynomials;
- * when they multiplied together and modularly reduced by an irreducible
- * polynomial of the 8th degree, the results are the field GF(2^8). The
- * specific irreducible polynomial that AES uses in hexadecimal is 0x11b.
- * This multiplication is associative with 0x01 as the identity:
- *
- * (b * 0x01 = GF(b, 0x01) = b).
- *
- * The operation GF(b, 0x02) can be performed at the byte level by left
- * shifting b once and then XOR'ing it (to perform the modular reduction)
- * with 0x11b if b is >= 128. Repeated application of the multiplication
- * of 0x02 can be used to implement the multiplication of any two bytes.
- *
- * For instance, multiplying 0x57 and 0x13, denoted as GF(0x57, 0x13), can
- * be performed by factoring 0x13 into 0x01, 0x02, and 0x10. Then these
- * factors can each be multiplied by 0x57 and then added together. To do
- * the multiplication, values for 0x57 multiplied by each of these 3 factors
- * can be precomputed and stored in a table. To add them, the values from
- * the table are XOR'd together.
- *
- * AES also defines addition and multiplication of words, that is 4-byte
- * numbers represented as polynomials of 3 degrees where the coefficients
- * are the values of the bytes.
- *
- * The word [a0, a1, a2, a3] is a polynomial a3x^3 + a2x^2 + a1x + a0.
- *
- * Addition is performed by XOR'ing like powers of x. Multiplication
- * is performed in two steps, the first is an algebriac expansion as
- * you would do normally (where addition is XOR). But the result is
- * a polynomial larger than 3 degrees and thus it cannot fit in a word. So
- * next the result is modularly reduced by an AES-specific polynomial of
- * degree 4 which will always produce a polynomial of less than 4 degrees
- * such that it will fit in a word. In AES, this polynomial is x^4 + 1.
- *
- * The modular product of two polynomials 'a' and 'b' is thus:
- *
- * d(x) = d3x^3 + d2x^2 + d1x + d0
- * with
- * d0 = GF(a0, b0) ^ GF(a3, b1) ^ GF(a2, b2) ^ GF(a1, b3)
- * d1 = GF(a1, b0) ^ GF(a0, b1) ^ GF(a3, b2) ^ GF(a2, b3)
- * d2 = GF(a2, b0) ^ GF(a1, b1) ^ GF(a0, b2) ^ GF(a3, b3)
- * d3 = GF(a3, b0) ^ GF(a2, b1) ^ GF(a1, b2) ^ GF(a0, b3)
- *
- * As a matrix:
- *
- * [d0] = [a0 a3 a2 a1][b0]
- * [d1] [a1 a0 a3 a2][b1]
- * [d2] [a2 a1 a0 a3][b2]
- * [d3] [a3 a2 a1 a0][b3]
- *
- * Special polynomials defined by AES (0x02 == {02}):
- * a(x) = {03}x^3 + {01}x^2 + {01}x + {02}
- * a^-1(x) = {0b}x^3 + {0d}x^2 + {09}x + {0e}.
- *
- * These polynomials are used in the MixColumns() and InverseMixColumns()
- * operations, respectively, to cause each element in the state to affect
- * the output (referred to as diffusing).
- *
- * RotWord() uses: a0 = a1 = a2 = {00} and a3 = {01}, which is the
- * polynomial x3.
- *
- * The ShiftRows() method modifies the last 3 rows in the state (where
- * the state is 4 words with 4 bytes per word) by shifting bytes cyclically.
- * The 1st byte in the second row is moved to the end of the row. The 1st
- * and 2nd bytes in the third row are moved to the end of the row. The 1st,
- * 2nd, and 3rd bytes are moved in the fourth row.
- *
- * More details on how AES arithmetic works:
- *
- * In the polynomial representation of binary numbers, XOR performs addition
- * and subtraction and multiplication in GF(2^8) denoted as GF(a, b)
- * corresponds with the multiplication of polynomials modulo an irreducible
- * polynomial of degree 8. In other words, for AES, GF(a, b) will multiply
- * polynomial 'a' with polynomial 'b' and then do a modular reduction by
- * an AES-specific irreducible polynomial of degree 8.
- *
- * A polynomial is irreducible if its only divisors are one and itself. For
- * the AES algorithm, this irreducible polynomial is:
- *
- * m(x) = x^8 + x^4 + x^3 + x + 1,
- *
- * or {01}{1b} in hexadecimal notation, where each coefficient is a bit:
- * 100011011 = 283 = 0x11b.
- *
- * For example, GF(0x57, 0x83) = 0xc1 because
- *
- * 0x57 = 87 = 01010111 = x^6 + x^4 + x^2 + x + 1
- * 0x85 = 131 = 10000101 = x^7 + x + 1
- *
- * (x^6 + x^4 + x^2 + x + 1) * (x^7 + x + 1)
- * = x^13 + x^11 + x^9 + x^8 + x^7 +
- * x^7 + x^5 + x^3 + x^2 + x +
- * x^6 + x^4 + x^2 + x + 1
- * = x^13 + x^11 + x^9 + x^8 + x^6 + x^5 + x^4 + x^3 + 1 = y
- * y modulo (x^8 + x^4 + x^3 + x + 1)
- * = x^7 + x^6 + 1.
- *
- * The modular reduction by m(x) guarantees the result will be a binary
- * polynomial of less than degree 8, so that it can fit in a byte.
- *
- * The operation to multiply a binary polynomial b with x (the polynomial
- * x in binary representation is 00000010) is:
- *
- * b_7x^8 + b_6x^7 + b_5x^6 + b_4x^5 + b_3x^4 + b_2x^3 + b_1x^2 + b_0x^1
- *
- * To get GF(b, x) we must reduce that by m(x). If b_7 is 0 (that is the
- * most significant bit is 0 in b) then the result is already reduced. If
- * it is 1, then we can reduce it by subtracting m(x) via an XOR.
- *
- * It follows that multiplication by x (00000010 or 0x02) can be implemented
- * by performing a left shift followed by a conditional bitwise XOR with
- * 0x1b. This operation on bytes is denoted by xtime(). Multiplication by
- * higher powers of x can be implemented by repeated application of xtime().
- *
- * By adding intermediate results, multiplication by any constant can be
- * implemented. For instance:
- *
- * GF(0x57, 0x13) = 0xfe because:
- *
- * xtime(b) = (b & 128) ? (b << 1 ^ 0x11b) : (b << 1)
- *
- * Note: We XOR with 0x11b instead of 0x1b because in javascript our
- * datatype for b can be larger than 1 byte, so a left shift will not
- * automatically eliminate bits that overflow a byte ... by XOR'ing the
- * overflow bit with 1 (the extra one from 0x11b) we zero it out.
- *
- * GF(0x57, 0x02) = xtime(0x57) = 0xae
- * GF(0x57, 0x04) = xtime(0xae) = 0x47
- * GF(0x57, 0x08) = xtime(0x47) = 0x8e
- * GF(0x57, 0x10) = xtime(0x8e) = 0x07
- *
- * GF(0x57, 0x13) = GF(0x57, (0x01 ^ 0x02 ^ 0x10))
- *
- * And by the distributive property (since XOR is addition and GF() is
- * multiplication):
- *
- * = GF(0x57, 0x01) ^ GF(0x57, 0x02) ^ GF(0x57, 0x10)
- * = 0x57 ^ 0xae ^ 0x07
- * = 0xfe.
- */
-function initialize() {
- init = true;
-
- /* Populate the Rcon table. These are the values given by
- [x^(i-1),{00},{00},{00}] where x^(i-1) are powers of x (and x = 0x02)
- in the field of GF(2^8), where i starts at 1.
-
- rcon[0] = [0x00, 0x00, 0x00, 0x00]
- rcon[1] = [0x01, 0x00, 0x00, 0x00] 2^(1-1) = 2^0 = 1
- rcon[2] = [0x02, 0x00, 0x00, 0x00] 2^(2-1) = 2^1 = 2
- ...
- rcon[9] = [0x1B, 0x00, 0x00, 0x00] 2^(9-1) = 2^8 = 0x1B
- rcon[10] = [0x36, 0x00, 0x00, 0x00] 2^(10-1) = 2^9 = 0x36
-
- We only store the first byte because it is the only one used.
- */
- rcon = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36];
-
- // compute xtime table which maps i onto GF(i, 0x02)
- var xtime = new Array(256);
- for(var i = 0; i < 128; ++i) {
- xtime[i] = i << 1;
- xtime[i + 128] = (i + 128) << 1 ^ 0x11B;
- }
-
- // compute all other tables
- sbox = new Array(256);
- isbox = new Array(256);
- mix = new Array(4);
- imix = new Array(4);
- for(var i = 0; i < 4; ++i) {
- mix[i] = new Array(256);
- imix[i] = new Array(256);
- }
- var e = 0, ei = 0, e2, e4, e8, sx, sx2, me, ime;
- for(var i = 0; i < 256; ++i) {
- /* We need to generate the SubBytes() sbox and isbox tables so that
- we can perform byte substitutions. This requires us to traverse
- all of the elements in GF, find their multiplicative inverses,
- and apply to each the following affine transformation:
-
- bi' = bi ^ b(i + 4) mod 8 ^ b(i + 5) mod 8 ^ b(i + 6) mod 8 ^
- b(i + 7) mod 8 ^ ci
- for 0 <= i < 8, where bi is the ith bit of the byte, and ci is the
- ith bit of a byte c with the value {63} or {01100011}.
-
- It is possible to traverse every possible value in a Galois field
- using what is referred to as a 'generator'. There are many
- generators (128 out of 256): 3,5,6,9,11,82 to name a few. To fully
- traverse GF we iterate 255 times, multiplying by our generator
- each time.
-
- On each iteration we can determine the multiplicative inverse for
- the current element.
-
- Suppose there is an element in GF 'e'. For a given generator 'g',
- e = g^x. The multiplicative inverse of e is g^(255 - x). It turns
- out that if use the inverse of a generator as another generator
- it will produce all of the corresponding multiplicative inverses
- at the same time. For this reason, we choose 5 as our inverse
- generator because it only requires 2 multiplies and 1 add and its
- inverse, 82, requires relatively few operations as well.
-
- In order to apply the affine transformation, the multiplicative
- inverse 'ei' of 'e' can be repeatedly XOR'd (4 times) with a
- bit-cycling of 'ei'. To do this 'ei' is first stored in 's' and
- 'x'. Then 's' is left shifted and the high bit of 's' is made the
- low bit. The resulting value is stored in 's'. Then 'x' is XOR'd
- with 's' and stored in 'x'. On each subsequent iteration the same
- operation is performed. When 4 iterations are complete, 'x' is
- XOR'd with 'c' (0x63) and the transformed value is stored in 'x'.
- For example:
-
- s = 01000001
- x = 01000001
-
- iteration 1: s = 10000010, x ^= s
- iteration 2: s = 00000101, x ^= s
- iteration 3: s = 00001010, x ^= s
- iteration 4: s = 00010100, x ^= s
- x ^= 0x63
-
- This can be done with a loop where s = (s << 1) | (s >> 7). However,
- it can also be done by using a single 16-bit (in this case 32-bit)
- number 'sx'. Since XOR is an associative operation, we can set 'sx'
- to 'ei' and then XOR it with 'sx' left-shifted 1,2,3, and 4 times.
- The most significant bits will flow into the high 8 bit positions
- and be correctly XOR'd with one another. All that remains will be
- to cycle the high 8 bits by XOR'ing them all with the lower 8 bits
- afterwards.
-
- At the same time we're populating sbox and isbox we can precompute
- the multiplication we'll need to do to do MixColumns() later.
- */
-
- // apply affine transformation
- sx = ei ^ (ei << 1) ^ (ei << 2) ^ (ei << 3) ^ (ei << 4);
- sx = (sx >> 8) ^ (sx & 255) ^ 0x63;
-
- // update tables
- sbox[e] = sx;
- isbox[sx] = e;
-
- /* Mixing columns is done using matrix multiplication. The columns
- that are to be mixed are each a single word in the current state.
- The state has Nb columns (4 columns). Therefore each column is a
- 4 byte word. So to mix the columns in a single column 'c' where
- its rows are r0, r1, r2, and r3, we use the following matrix
- multiplication:
-
- [2 3 1 1]*[r0,c]=[r'0,c]
- [1 2 3 1] [r1,c] [r'1,c]
- [1 1 2 3] [r2,c] [r'2,c]
- [3 1 1 2] [r3,c] [r'3,c]
-
- r0, r1, r2, and r3 are each 1 byte of one of the words in the
- state (a column). To do matrix multiplication for each mixed
- column c' we multiply the corresponding row from the left matrix
- with the corresponding column from the right matrix. In total, we
- get 4 equations:
-
- r0,c' = 2*r0,c + 3*r1,c + 1*r2,c + 1*r3,c
- r1,c' = 1*r0,c + 2*r1,c + 3*r2,c + 1*r3,c
- r2,c' = 1*r0,c + 1*r1,c + 2*r2,c + 3*r3,c
- r3,c' = 3*r0,c + 1*r1,c + 1*r2,c + 2*r3,c
-
- As usual, the multiplication is as previously defined and the
- addition is XOR. In order to optimize mixing columns we can store
- the multiplication results in tables. If you think of the whole
- column as a word (it might help to visualize by mentally rotating
- the equations above by counterclockwise 90 degrees) then you can
- see that it would be useful to map the multiplications performed on
- each byte (r0, r1, r2, r3) onto a word as well. For instance, we
- could map 2*r0,1*r0,1*r0,3*r0 onto a word by storing 2*r0 in the
- highest 8 bits and 3*r0 in the lowest 8 bits (with the other two
- respectively in the middle). This means that a table can be
- constructed that uses r0 as an index to the word. We can do the
- same with r1, r2, and r3, creating a total of 4 tables.
-
- To construct a full c', we can just look up each byte of c in
- their respective tables and XOR the results together.
-
- Also, to build each table we only have to calculate the word
- for 2,1,1,3 for every byte ... which we can do on each iteration
- of this loop since we will iterate over every byte. After we have
- calculated 2,1,1,3 we can get the results for the other tables
- by cycling the byte at the end to the beginning. For instance
- we can take the result of table 2,1,1,3 and produce table 3,2,1,1
- by moving the right most byte to the left most position just like
- how you can imagine the 3 moved out of 2,1,1,3 and to the front
- to produce 3,2,1,1.
-
- There is another optimization in that the same multiples of
- the current element we need in order to advance our generator
- to the next iteration can be reused in performing the 2,1,1,3
- calculation. We also calculate the inverse mix column tables,
- with e,9,d,b being the inverse of 2,1,1,3.
-
- When we're done, and we need to actually mix columns, the first
- byte of each state word should be put through mix[0] (2,1,1,3),
- the second through mix[1] (3,2,1,1) and so forth. Then they should
- be XOR'd together to produce the fully mixed column.
- */
-
- // calculate mix and imix table values
- sx2 = xtime[sx];
- e2 = xtime[e];
- e4 = xtime[e2];
- e8 = xtime[e4];
- me =
- (sx2 << 24) ^ // 2
- (sx << 16) ^ // 1
- (sx << 8) ^ // 1
- (sx ^ sx2); // 3
- ime =
- (e2 ^ e4 ^ e8) << 24 ^ // E (14)
- (e ^ e8) << 16 ^ // 9
- (e ^ e4 ^ e8) << 8 ^ // D (13)
- (e ^ e2 ^ e8); // B (11)
- // produce each of the mix tables by rotating the 2,1,1,3 value
- for(var n = 0; n < 4; ++n) {
- mix[n][e] = me;
- imix[n][sx] = ime;
- // cycle the right most byte to the left most position
- // ie: 2,1,1,3 becomes 3,2,1,1
- me = me << 24 | me >>> 8;
- ime = ime << 24 | ime >>> 8;
- }
-
- // get next element and inverse
- if(e === 0) {
- // 1 is the inverse of 1
- e = ei = 1;
- } else {
- // e = 2e + 2*2*2*(10e)) = multiply e by 82 (chosen generator)
- // ei = ei + 2*2*ei = multiply ei by 5 (inverse generator)
- e = e2 ^ xtime[xtime[xtime[e2 ^ e8]]];
- ei ^= xtime[xtime[ei]];
- }
- }
-}
-
-/**
- * Generates a key schedule using the AES key expansion algorithm.
- *
- * The AES algorithm takes the Cipher Key, K, and performs a Key Expansion
- * routine to generate a key schedule. The Key Expansion generates a total
- * of Nb*(Nr + 1) words: the algorithm requires an initial set of Nb words,
- * and each of the Nr rounds requires Nb words of key data. The resulting
- * key schedule consists of a linear array of 4-byte words, denoted [wi ],
- * with i in the range 0 ≤ i < Nb(Nr + 1).
- *
- * KeyExpansion(byte key[4*Nk], word w[Nb*(Nr+1)], Nk)
- * AES-128 (Nb=4, Nk=4, Nr=10)
- * AES-192 (Nb=4, Nk=6, Nr=12)
- * AES-256 (Nb=4, Nk=8, Nr=14)
- * Note: Nr=Nk+6.
- *
- * Nb is the number of columns (32-bit words) comprising the State (or
- * number of bytes in a block). For AES, Nb=4.
- *
- * @param key the key to schedule (as an array of 32-bit words).
- * @param decrypt true to modify the key schedule to decrypt, false not to.
- *
- * @return the generated key schedule.
- */
-function _expandKey(key, decrypt) {
- // copy the key's words to initialize the key schedule
- var w = key.slice(0);
-
- /* RotWord() will rotate a word, moving the first byte to the last
- byte's position (shifting the other bytes left).
-
- We will be getting the value of Rcon at i / Nk. 'i' will iterate
- from Nk to (Nb * Nr+1). Nk = 4 (4 byte key), Nb = 4 (4 words in
- a block), Nr = Nk + 6 (10). Therefore 'i' will iterate from
- 4 to 44 (exclusive). Each time we iterate 4 times, i / Nk will
- increase by 1. We use a counter iNk to keep track of this.
- */
-
- // go through the rounds expanding the key
- var temp, iNk = 1;
- var Nk = w.length;
- var Nr1 = Nk + 6 + 1;
- var end = Nb * Nr1;
- for(var i = Nk; i < end; ++i) {
- temp = w[i - 1];
- if(i % Nk === 0) {
- // temp = SubWord(RotWord(temp)) ^ Rcon[i / Nk]
- temp =
- sbox[temp >>> 16 & 255] << 24 ^
- sbox[temp >>> 8 & 255] << 16 ^
- sbox[temp & 255] << 8 ^
- sbox[temp >>> 24] ^ (rcon[iNk] << 24);
- iNk++;
- } else if(Nk > 6 && (i % Nk === 4)) {
- // temp = SubWord(temp)
- temp =
- sbox[temp >>> 24] << 24 ^
- sbox[temp >>> 16 & 255] << 16 ^
- sbox[temp >>> 8 & 255] << 8 ^
- sbox[temp & 255];
- }
- w[i] = w[i - Nk] ^ temp;
- }
-
- /* When we are updating a cipher block we always use the code path for
- encryption whether we are decrypting or not (to shorten code and
- simplify the generation of look up tables). However, because there
- are differences in the decryption algorithm, other than just swapping
- in different look up tables, we must transform our key schedule to
- account for these changes:
-
- 1. The decryption algorithm gets its key rounds in reverse order.
- 2. The decryption algorithm adds the round key before mixing columns
- instead of afterwards.
-
- We don't need to modify our key schedule to handle the first case,
- we can just traverse the key schedule in reverse order when decrypting.
-
- The second case requires a little work.
-
- The tables we built for performing rounds will take an input and then
- perform SubBytes() and MixColumns() or, for the decrypt version,
- InvSubBytes() and InvMixColumns(). But the decrypt algorithm requires
- us to AddRoundKey() before InvMixColumns(). This means we'll need to
- apply some transformations to the round key to inverse-mix its columns
- so they'll be correct for moving AddRoundKey() to after the state has
- had its columns inverse-mixed.
-
- To inverse-mix the columns of the state when we're decrypting we use a
- lookup table that will apply InvSubBytes() and InvMixColumns() at the
- same time. However, the round key's bytes are not inverse-substituted
- in the decryption algorithm. To get around this problem, we can first
- substitute the bytes in the round key so that when we apply the
- transformation via the InvSubBytes()+InvMixColumns() table, it will
- undo our substitution leaving us with the original value that we
- want -- and then inverse-mix that value.
-
- This change will correctly alter our key schedule so that we can XOR
- each round key with our already transformed decryption state. This
- allows us to use the same code path as the encryption algorithm.
-
- We make one more change to the decryption key. Since the decryption
- algorithm runs in reverse from the encryption algorithm, we reverse
- the order of the round keys to avoid having to iterate over the key
- schedule backwards when running the encryption algorithm later in
- decryption mode. In addition to reversing the order of the round keys,
- we also swap each round key's 2nd and 4th rows. See the comments
- section where rounds are performed for more details about why this is
- done. These changes are done inline with the other substitution
- described above.
- */
- if(decrypt) {
- var tmp;
- var m0 = imix[0];
- var m1 = imix[1];
- var m2 = imix[2];
- var m3 = imix[3];
- var wnew = w.slice(0);
- end = w.length;
- for(var i = 0, wi = end - Nb; i < end; i += Nb, wi -= Nb) {
- // do not sub the first or last round key (round keys are Nb
- // words) as no column mixing is performed before they are added,
- // but do change the key order
- if(i === 0 || i === (end - Nb)) {
- wnew[i] = w[wi];
- wnew[i + 1] = w[wi + 3];
- wnew[i + 2] = w[wi + 2];
- wnew[i + 3] = w[wi + 1];
- } else {
- // substitute each round key byte because the inverse-mix
- // table will inverse-substitute it (effectively cancel the
- // substitution because round key bytes aren't sub'd in
- // decryption mode) and swap indexes 3 and 1
- for(var n = 0; n < Nb; ++n) {
- tmp = w[wi + n];
- wnew[i + (3&-n)] =
- m0[sbox[tmp >>> 24]] ^
- m1[sbox[tmp >>> 16 & 255]] ^
- m2[sbox[tmp >>> 8 & 255]] ^
- m3[sbox[tmp & 255]];
- }
- }
- }
- w = wnew;
- }
-
- return w;
-}
-
-/**
- * Updates a single block (16 bytes) using AES. The update will either
- * encrypt or decrypt the block.
- *
- * @param w the key schedule.
- * @param input the input block (an array of 32-bit words).
- * @param output the updated output block.
- * @param decrypt true to decrypt the block, false to encrypt it.
- */
-function _updateBlock(w, input, output, decrypt) {
- /*
- Cipher(byte in[4*Nb], byte out[4*Nb], word w[Nb*(Nr+1)])
- begin
- byte state[4,Nb]
- state = in
- AddRoundKey(state, w[0, Nb-1])
- for round = 1 step 1 to Nr–1
- SubBytes(state)
- ShiftRows(state)
- MixColumns(state)
- AddRoundKey(state, w[round*Nb, (round+1)*Nb-1])
- end for
- SubBytes(state)
- ShiftRows(state)
- AddRoundKey(state, w[Nr*Nb, (Nr+1)*Nb-1])
- out = state
- end
-
- InvCipher(byte in[4*Nb], byte out[4*Nb], word w[Nb*(Nr+1)])
- begin
- byte state[4,Nb]
- state = in
- AddRoundKey(state, w[Nr*Nb, (Nr+1)*Nb-1])
- for round = Nr-1 step -1 downto 1
- InvShiftRows(state)
- InvSubBytes(state)
- AddRoundKey(state, w[round*Nb, (round+1)*Nb-1])
- InvMixColumns(state)
- end for
- InvShiftRows(state)
- InvSubBytes(state)
- AddRoundKey(state, w[0, Nb-1])
- out = state
- end
- */
-
- // Encrypt: AddRoundKey(state, w[0, Nb-1])
- // Decrypt: AddRoundKey(state, w[Nr*Nb, (Nr+1)*Nb-1])
- var Nr = w.length / 4 - 1;
- var m0, m1, m2, m3, sub;
- if(decrypt) {
- m0 = imix[0];
- m1 = imix[1];
- m2 = imix[2];
- m3 = imix[3];
- sub = isbox;
- } else {
- m0 = mix[0];
- m1 = mix[1];
- m2 = mix[2];
- m3 = mix[3];
- sub = sbox;
- }
- var a, b, c, d, a2, b2, c2;
- a = input[0] ^ w[0];
- b = input[decrypt ? 3 : 1] ^ w[1];
- c = input[2] ^ w[2];
- d = input[decrypt ? 1 : 3] ^ w[3];
- var i = 3;
-
- /* In order to share code we follow the encryption algorithm when both
- encrypting and decrypting. To account for the changes required in the
- decryption algorithm, we use different lookup tables when decrypting
- and use a modified key schedule to account for the difference in the
- order of transformations applied when performing rounds. We also get
- key rounds in reverse order (relative to encryption). */
- for(var round = 1; round < Nr; ++round) {
- /* As described above, we'll be using table lookups to perform the
- column mixing. Each column is stored as a word in the state (the
- array 'input' has one column as a word at each index). In order to
- mix a column, we perform these transformations on each row in c,
- which is 1 byte in each word. The new column for c0 is c'0:
-
- m0 m1 m2 m3
- r0,c'0 = 2*r0,c0 + 3*r1,c0 + 1*r2,c0 + 1*r3,c0
- r1,c'0 = 1*r0,c0 + 2*r1,c0 + 3*r2,c0 + 1*r3,c0
- r2,c'0 = 1*r0,c0 + 1*r1,c0 + 2*r2,c0 + 3*r3,c0
- r3,c'0 = 3*r0,c0 + 1*r1,c0 + 1*r2,c0 + 2*r3,c0
-
- So using mix tables where c0 is a word with r0 being its upper
- 8 bits and r3 being its lower 8 bits:
-
- m0[c0 >> 24] will yield this word: [2*r0,1*r0,1*r0,3*r0]
- ...
- m3[c0 & 255] will yield this word: [1*r3,1*r3,3*r3,2*r3]
-
- Therefore to mix the columns in each word in the state we
- do the following (& 255 omitted for brevity):
- c'0,r0 = m0[c0 >> 24] ^ m1[c1 >> 16] ^ m2[c2 >> 8] ^ m3[c3]
- c'0,r1 = m0[c0 >> 24] ^ m1[c1 >> 16] ^ m2[c2 >> 8] ^ m3[c3]
- c'0,r2 = m0[c0 >> 24] ^ m1[c1 >> 16] ^ m2[c2 >> 8] ^ m3[c3]
- c'0,r3 = m0[c0 >> 24] ^ m1[c1 >> 16] ^ m2[c2 >> 8] ^ m3[c3]
-
- However, before mixing, the algorithm requires us to perform
- ShiftRows(). The ShiftRows() transformation cyclically shifts the
- last 3 rows of the state over different offsets. The first row
- (r = 0) is not shifted.
-
- s'_r,c = s_r,(c + shift(r, Nb) mod Nb
- for 0 < r < 4 and 0 <= c < Nb and
- shift(1, 4) = 1
- shift(2, 4) = 2
- shift(3, 4) = 3.
-
- This causes the first byte in r = 1 to be moved to the end of
- the row, the first 2 bytes in r = 2 to be moved to the end of
- the row, the first 3 bytes in r = 3 to be moved to the end of
- the row:
-
- r1: [c0 c1 c2 c3] => [c1 c2 c3 c0]
- r2: [c0 c1 c2 c3] [c2 c3 c0 c1]
- r3: [c0 c1 c2 c3] [c3 c0 c1 c2]
-
- We can make these substitutions inline with our column mixing to
- generate an updated set of equations to produce each word in the
- state (note the columns have changed positions):
-
- c0 c1 c2 c3 => c0 c1 c2 c3
- c0 c1 c2 c3 c1 c2 c3 c0 (cycled 1 byte)
- c0 c1 c2 c3 c2 c3 c0 c1 (cycled 2 bytes)
- c0 c1 c2 c3 c3 c0 c1 c2 (cycled 3 bytes)
-
- Therefore:
-
- c'0 = 2*r0,c0 + 3*r1,c1 + 1*r2,c2 + 1*r3,c3
- c'0 = 1*r0,c0 + 2*r1,c1 + 3*r2,c2 + 1*r3,c3
- c'0 = 1*r0,c0 + 1*r1,c1 + 2*r2,c2 + 3*r3,c3
- c'0 = 3*r0,c0 + 1*r1,c1 + 1*r2,c2 + 2*r3,c3
-
- c'1 = 2*r0,c1 + 3*r1,c2 + 1*r2,c3 + 1*r3,c0
- c'1 = 1*r0,c1 + 2*r1,c2 + 3*r2,c3 + 1*r3,c0
- c'1 = 1*r0,c1 + 1*r1,c2 + 2*r2,c3 + 3*r3,c0
- c'1 = 3*r0,c1 + 1*r1,c2 + 1*r2,c3 + 2*r3,c0
-
- ... and so forth for c'2 and c'3. The important distinction is
- that the columns are cycling, with c0 being used with the m0
- map when calculating c0, but c1 being used with the m0 map when
- calculating c1 ... and so forth.
-
- When performing the inverse we transform the mirror image and
- skip the bottom row, instead of the top one, and move upwards:
-
- c3 c2 c1 c0 => c0 c3 c2 c1 (cycled 3 bytes) *same as encryption
- c3 c2 c1 c0 c1 c0 c3 c2 (cycled 2 bytes)
- c3 c2 c1 c0 c2 c1 c0 c3 (cycled 1 byte) *same as encryption
- c3 c2 c1 c0 c3 c2 c1 c0
-
- If you compare the resulting matrices for ShiftRows()+MixColumns()
- and for InvShiftRows()+InvMixColumns() the 2nd and 4th columns are
- different (in encrypt mode vs. decrypt mode). So in order to use
- the same code to handle both encryption and decryption, we will
- need to do some mapping.
-
- If in encryption mode we let a=c0, b=c1, c=c2, d=c3, and r<N> be
- a row number in the state, then the resulting matrix in encryption
- mode for applying the above transformations would be:
-
- r1: a b c d
- r2: b c d a
- r3: c d a b
- r4: d a b c
-
- If we did the same in decryption mode we would get:
-
- r1: a d c b
- r2: b a d c
- r3: c b a d
- r4: d c b a
-
- If instead we swap d and b (set b=c3 and d=c1), then we get:
-
- r1: a b c d
- r2: d a b c
- r3: c d a b
- r4: b c d a
-
- Now the 1st and 3rd rows are the same as the encryption matrix. All
- we need to do then to make the mapping exactly the same is to swap
- the 2nd and 4th rows when in decryption mode. To do this without
- having to do it on each iteration, we swapped the 2nd and 4th rows
- in the decryption key schedule. We also have to do the swap above
- when we first pull in the input and when we set the final output. */
- a2 =
- m0[a >>> 24] ^
- m1[b >>> 16 & 255] ^
- m2[c >>> 8 & 255] ^
- m3[d & 255] ^ w[++i];
- b2 =
- m0[b >>> 24] ^
- m1[c >>> 16 & 255] ^
- m2[d >>> 8 & 255] ^
- m3[a & 255] ^ w[++i];
- c2 =
- m0[c >>> 24] ^
- m1[d >>> 16 & 255] ^
- m2[a >>> 8 & 255] ^
- m3[b & 255] ^ w[++i];
- d =
- m0[d >>> 24] ^
- m1[a >>> 16 & 255] ^
- m2[b >>> 8 & 255] ^
- m3[c & 255] ^ w[++i];
- a = a2;
- b = b2;
- c = c2;
- }
-
- /*
- Encrypt:
- SubBytes(state)
- ShiftRows(state)
- AddRoundKey(state, w[Nr*Nb, (Nr+1)*Nb-1])
-
- Decrypt:
- InvShiftRows(state)
- InvSubBytes(state)
- AddRoundKey(state, w[0, Nb-1])
- */
- // Note: rows are shifted inline
- output[0] =
- (sub[a >>> 24] << 24) ^
- (sub[b >>> 16 & 255] << 16) ^
- (sub[c >>> 8 & 255] << 8) ^
- (sub[d & 255]) ^ w[++i];
- output[decrypt ? 3 : 1] =
- (sub[b >>> 24] << 24) ^
- (sub[c >>> 16 & 255] << 16) ^
- (sub[d >>> 8 & 255] << 8) ^
- (sub[a & 255]) ^ w[++i];
- output[2] =
- (sub[c >>> 24] << 24) ^
- (sub[d >>> 16 & 255] << 16) ^
- (sub[a >>> 8 & 255] << 8) ^
- (sub[b & 255]) ^ w[++i];
- output[decrypt ? 1 : 3] =
- (sub[d >>> 24] << 24) ^
- (sub[a >>> 16 & 255] << 16) ^
- (sub[b >>> 8 & 255] << 8) ^
- (sub[c & 255]) ^ w[++i];
-}
-
-/**
- * Deprecated. Instead, use:
- *
- * forge.cipher.createCipher('AES-<mode>', key);
- * forge.cipher.createDecipher('AES-<mode>', key);
- *
- * Creates a deprecated AES cipher object. This object's mode will default to
- * CBC (cipher-block-chaining).
- *
- * The key and iv may be given as a string of bytes, an array of bytes, a
- * byte buffer, or an array of 32-bit words.
- *
- * @param options the options to use.
- * key the symmetric key to use.
- * output the buffer to write to.
- * decrypt true for decryption, false for encryption.
- * mode the cipher mode to use (default: 'CBC').
- *
- * @return the cipher.
- */
-function _createCipher(options) {
- options = options || {};
- var mode = (options.mode || 'CBC').toUpperCase();
- var algorithm = 'AES-' + mode;
-
- var cipher;
- if(options.decrypt) {
- cipher = forge.cipher.createDecipher(algorithm, options.key);
- } else {
- cipher = forge.cipher.createCipher(algorithm, options.key);
- }
-
- // backwards compatible start API
- var start = cipher.start;
- cipher.start = function(iv, options) {
- // backwards compatibility: support second arg as output buffer
- var output = null;
- if(options instanceof forge.util.ByteBuffer) {
- output = options;
- options = {};
- }
- options = options || {};
- options.output = output;
- options.iv = iv;
- start.call(cipher, options);
- };
-
- return cipher;
-}
-
-} // end module implementation
-
-/* ########## Begin module wrapper ########## */
-var name = 'aes';
-if(typeof define !== 'function') {
- // NodeJS -> AMD
- if(typeof module === 'object' && module.exports) {
- var nodeJS = true;
- define = function(ids, factory) {
- factory(require, module);
- };
- } else {
- // <script>
- if(typeof forge === 'undefined') {
- forge = {};
- }
- return initModule(forge);
- }
-}
-// AMD
-var deps;
-var defineFunc = function(require, module) {
- module.exports = function(forge) {
- var mods = deps.map(function(dep) {
- return require(dep);
- }).concat(initModule);
- // handle circular dependencies
- forge = forge || {};
- forge.defined = forge.defined || {};
- if(forge.defined[name]) {
- return forge[name];
- }
- forge.defined[name] = true;
- for(var i = 0; i < mods.length; ++i) {
- mods[i](forge);
- }
- return forge[name];
- };
-};
-var tmpDefine = define;
-define = function(ids, factory) {
- deps = (typeof ids === 'string') ? factory.slice(2) : ids.slice(2);
- if(nodeJS) {
- delete define;
- return tmpDefine.apply(null, Array.prototype.slice.call(arguments, 0));
- }
- define = tmpDefine;
- return define.apply(null, Array.prototype.slice.call(arguments, 0));
-};
-define(
- ['require', 'module', './cipher', './cipherModes', './util'], function() {
- defineFunc.apply(null, Array.prototype.slice.call(arguments, 0));
-});
-})();
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