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Add the SM4 block cipher, also a no-padding option for decrypting block ciphers. #1189

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Mar 29, 2022
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Add the SM4 block cipher, also a no-padding option for decrypting block ciphers. #1189

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2 changes: 2 additions & 0 deletions src/core/config/Categories.json
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Expand Up @@ -83,6 +83,8 @@
"ROT47",
"XOR",
"XOR Brute Force",
"SM4 Encrypt",
"SM4 Decrypt",
"Vigenère Encode",
"Vigenère Decode",
"To Morse Code",
Expand Down
329 changes: 329 additions & 0 deletions src/core/lib/SM4.mjs
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@@ -0,0 +1,329 @@
/**
* Complete implementation of SM4 cipher encryption/decryption with
* ECB, CBC, CFB, OFB, CTR block modes.
* These modes are specified in IETF draft-ribose-cfrg-sm4-09, see:
* https://tools.ietf.org/id/draft-ribose-cfrg-sm4-09.html
* for details.
*
* Follows spec from Cryptography Standardization Technical Comittee:
* http://www.gmbz.org.cn/upload/2018-04-04/1522788048733065051.pdf
*
* @author swesven
* @copyright 2021
* @license Apache-2.0
*/

import OperationError from "../errors/OperationError.mjs";

/** Number of rounds */
const NROUNDS = 32;

/** block size in bytes */
const BLOCKSIZE = 16;

/** The S box, 256 8-bit values */
const Sbox = [
0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48];

/** "Fixed parameter CK" used in key expansion */
const CK = [
0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
];

/** "System parameter FK" */
const FK = [0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc];

/**
* Rotating 32-bit shift left
*
* (Note that although JS integers are stored in doubles and thus have 53 bits,
* the JS bitwise operations are 32-bit)
*/
function ROL(i, n) {
return (i << n) | (i >>> (32 - n));
}

/**
* Linear transformation L
*
* @param {integer} b - a 32 bit integer
*/
function transformL(b) {
/* Replace each of the 4 bytes in b with the value at its offset in the Sbox */
b = (Sbox[(b >>> 24) & 0xFF] << 24) | (Sbox[(b >>> 16) & 0xFF] << 16) |
(Sbox[(b >>> 8) & 0xFF] << 8) | Sbox[b & 0xFF];
/* circular rotate and xor */
return b ^ ROL(b, 2) ^ ROL(b, 10) ^ ROL(b, 18) ^ ROL(b, 24);
}

/**
* Linear transformation L'
*
* @param {integer} b - a 32 bit integer
*/
function transformLprime(b) {
/* Replace each of the 4 bytes in b with the value at its offset in the Sbox */
b = (Sbox[(b >>> 24) & 0xFF] << 24) | (Sbox[(b >>> 16) & 0xFF] << 16) |
(Sbox[(b >>> 8) & 0xFF] << 8) | Sbox[b & 0xFF];
return b ^ ROL(b, 13) ^ ROL(b, 23); /* circular rotate and XOR */
}

/**
* Initialize the round key
*/
function initSM4RoundKey(rawkey) {
const K = rawkey.map((a, i) => a ^ FK[i]); /* K = rawkey ^ FK */
const roundKey = [];
for (let i = 0; i < 32; i++)
roundKey[i] = K[i + 4] = K[i] ^ transformLprime(K[i + 1] ^ K[i + 2] ^ K[i + 3] ^ CK[i]);
return roundKey;
}

/**
* Encrypts/decrypts a single block X (4 32-bit values) with a prepared round key.
*
* @param {intArray} X - A cleartext block.
* @param {intArray} roundKey - The round key from initSMRoundKey for encrypting (reversed for decrypting).
* @returns {byteArray} - The cipher text.
*/
function encryptBlockSM4(X, roundKey) {
for (let i = 0; i < NROUNDS; i++)
X[i + 4] = X[i] ^ transformL(X[i + 1] ^ X[i + 2] ^ X[i + 3] ^ roundKey[i]);
return [X[35], X[34], X[33], X[32]];
}

/**
* Takes 16 bytes from an offset in an array and returns an array of 4 32-bit Big-Endian values.
* (DataView won't work portably here as we need Big-Endian)
*
* @param {byteArray} bArray - the array of bytes
* @param {integer} offset - starting offset in the array; 15 bytes must follow it.
*/
function bytesToInts(bArray, offs=0) {
let offset = offs;
const A = (bArray[offset] << 24) | (bArray[offset + 1] << 16) | (bArray[offset + 2] << 8) | bArray[offset + 3];
offset += 4;
const B = (bArray[offset] << 24) | (bArray[offset + 1] << 16) | (bArray[offset + 2] << 8) | bArray[offset + 3];
offset += 4;
const C = (bArray[offset] << 24) | (bArray[offset + 1] << 16) | (bArray[offset + 2] << 8) | bArray[offset + 3];
offset += 4;
const D = (bArray[offset] << 24) | (bArray[offset + 1] << 16) | (bArray[offset + 2] << 8) | bArray[offset + 3];
return [A, B, C, D];
}

/**
* Inverse of bytesToInts above; takes an array of 32-bit integers and turns it into an array of bytes.
* Again, Big-Endian order.
*/
function intsToBytes(ints) {
const bArr = [];
for (let i = 0; i < ints.length; i++) {
bArr.push((ints[i] >> 24) & 0xFF);
bArr.push((ints[i] >> 16) & 0xFF);
bArr.push((ints[i] >> 8) & 0xFF);
bArr.push(ints[i] & 0xFF);
}
return bArr;
}

/**
* Encrypt using SM4 using a given block cipher mode.
*
* @param {byteArray} message - The clear text message; any length under 32 Gb or so.
* @param {byteArray} key - The cipher key, 16 bytes.
* @param {byteArray} iv - The IV or nonce, 16 bytes (not used with ECB mode)
* @param {string} mode - The block cipher mode "CBC", "ECB", "CFB", "OFB", "CTR".
* @param {boolean} noPadding - Don't add PKCS#7 padding if set.
* @returns {byteArray} - The cipher text.
*/
export function encryptSM4(message, key, iv, mode="ECB", noPadding=false) {
const messageLength = message.length;
if (messageLength === 0)
return [];
const roundKey = initSM4RoundKey(bytesToInts(key, 0));

/* Pad with PKCS#7 if requested for ECB/CBC else add zeroes (which are sliced off at the end) */
let padByte = 0;
let nPadding = 16 - (message.length & 0xF);
if (mode === "ECB" || mode === "CBC") {
if (noPadding) {
if (nPadding !== 16)
throw new OperationError("No padding requested in "+mode+" mode but input is not a 16-byte multiple.");
nPadding = 0;
} else
padByte = nPadding;
}
for (let i = 0; i < nPadding; i++)
message.push(padByte);

const cipherText = [];
switch (mode) {
case "ECB":
for (let i = 0; i < message.length; i += BLOCKSIZE)
Array.prototype.push.apply(cipherText, intsToBytes(encryptBlockSM4(bytesToInts(message, i), roundKey)));
break;
case "CBC":
iv = bytesToInts(iv, 0);
for (let i = 0; i < message.length; i += BLOCKSIZE) {
const block = bytesToInts(message, i);
block[0] ^= iv[0]; block[1] ^= iv[1];
block[2] ^= iv[2]; block[3] ^= iv[3];
iv = encryptBlockSM4(block, roundKey);
Array.prototype.push.apply(cipherText, intsToBytes(iv));
}
break;
case "CFB":
iv = bytesToInts(iv, 0);
for (let i = 0; i < message.length; i += BLOCKSIZE) {
iv = encryptBlockSM4(iv, roundKey);
const block = bytesToInts(message, i);
block[0] ^= iv[0]; block[1] ^= iv[1];
block[2] ^= iv[2]; block[3] ^= iv[3];
Array.prototype.push.apply(cipherText, intsToBytes(block));
iv = block;
}
break;
case "OFB":
iv = bytesToInts(iv, 0);
for (let i = 0; i < message.length; i += BLOCKSIZE) {
iv = encryptBlockSM4(iv, roundKey);
const block = bytesToInts(message, i);
block[0] ^= iv[0]; block[1] ^= iv[1];
block[2] ^= iv[2]; block[3] ^= iv[3];
Array.prototype.push.apply(cipherText, intsToBytes(block));
}
break;
case "CTR":
iv = bytesToInts(iv, 0);
for (let i = 0; i < message.length; i += BLOCKSIZE) {
let iv2 = [...iv]; /* containing the IV + counter */
iv2[3] += (i >> 4);/* Using a 32 bit counter here. 64 Gb encrypts should be enough for everyone. */
iv2 = encryptBlockSM4(iv2, roundKey);
const block = bytesToInts(message, i);
block[0] ^= iv2[0]; block[1] ^= iv2[1];
block[2] ^= iv2[2]; block[3] ^= iv2[3];
Array.prototype.push.apply(cipherText, intsToBytes(block));
}
break;
default:
throw new OperationError("Invalid block cipher mode: "+mode);
}
if (mode !== "ECB" && mode !== "CBC")
return cipherText.slice(0, messageLength);
return cipherText;
}

/**
* Decrypt using SM4 using a given block cipher mode.
*
* @param {byteArray} cipherText - The ciphertext
* @param {byteArray} key - The cipher key, 16 bytes.
* @param {byteArray} iv - The IV or nonce, 16 bytes (not used with ECB mode)
* @param {string} mode - The block cipher mode "CBC", "ECB", "CFB", "OFB", "CTR"
* @param {boolean] ignorePadding - If true, ignore padding issues in ECB/CBC mode.
* @returns {byteArray} - The cipher text.
*/
export function decryptSM4(cipherText, key, iv, mode="ECB", ignorePadding=false) {
const originalLength = cipherText.length;
if (originalLength === 0)
return [];
let roundKey = initSM4RoundKey(bytesToInts(key, 0));

if (mode === "ECB" || mode === "CBC") {
/* Init decryption key */
roundKey = roundKey.reverse();
if ((originalLength & 0xF) !== 0 && !ignorePadding)
throw new OperationError("With ECB or CBC modes, the input must be divisible into 16 byte blocks. ("+(cipherText.length & 0xF)+" bytes extra)");
} else /* Pad dummy bytes for other modes, chop them off at the end */
while ((cipherText.length & 0xF) !== 0)
cipherText.push(0);

const clearText = [];
switch (mode) {
case "ECB":
for (let i = 0; i < cipherText.length; i += BLOCKSIZE)
Array.prototype.push.apply(clearText, intsToBytes(encryptBlockSM4(bytesToInts(cipherText, i), roundKey)));
break;
case "CBC":
iv = bytesToInts(iv, 0);
for (let i = 0; i < cipherText.length; i += BLOCKSIZE) {
const block = encryptBlockSM4(bytesToInts(cipherText, i), roundKey);
block[0] ^= iv[0]; block[1] ^= iv[1];
block[2] ^= iv[2]; block[3] ^= iv[3];
Array.prototype.push.apply(clearText, intsToBytes(block));
iv = bytesToInts(cipherText, i);
}
break;
case "CFB":
iv = bytesToInts(iv, 0);
for (let i = 0; i < cipherText.length; i += BLOCKSIZE) {
iv = encryptBlockSM4(iv, roundKey);
const block = bytesToInts(cipherText, i);
block[0] ^= iv[0]; block[1] ^= iv[1];
block[2] ^= iv[2]; block[3] ^= iv[3];
Array.prototype.push.apply(clearText, intsToBytes(block));
iv = bytesToInts(cipherText, i);
}
break;
case "OFB":
iv = bytesToInts(iv, 0);
for (let i = 0; i < cipherText.length; i += BLOCKSIZE) {
iv = encryptBlockSM4(iv, roundKey);
const block = bytesToInts(cipherText, i);
block[0] ^= iv[0]; block[1] ^= iv[1];
block[2] ^= iv[2]; block[3] ^= iv[3];
Array.prototype.push.apply(clearText, intsToBytes(block));
}
break;
case "CTR":
iv = bytesToInts(iv, 0);
for (let i = 0; i < cipherText.length; i += BLOCKSIZE) {
let iv2 = [...iv]; /* containing the IV + counter */
iv2[3] += (i >> 4);/* Using a 32 bit counter here. 64 Gb encrypts should be enough for everyone. */
iv2 = encryptBlockSM4(iv2, roundKey);
const block = bytesToInts(cipherText, i);
block[0] ^= iv2[0]; block[1] ^= iv2[1];
block[2] ^= iv2[2]; block[3] ^= iv2[3];
Array.prototype.push.apply(clearText, intsToBytes(block));
}
break;
default:
throw new OperationError("Invalid block cipher mode: "+mode);
}
/* Check PKCS#7 padding */
if (mode === "ECB" || mode === "CBC") {
if (ignorePadding)
return clearText;
const padByte = clearText[clearText.length - 1];
if (padByte > 16)
throw new OperationError("Invalid PKCS#7 padding.");
for (let i = 0; i < padByte; i++)
if (clearText[clearText.length -i - 1] !== padByte)
throw new OperationError("Invalid PKCS#7 padding.");
return clearText.slice(0, clearText.length - padByte);
}
return clearText.slice(0, originalLength);
}

18 changes: 16 additions & 2 deletions src/core/operations/AESDecrypt.mjs
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Expand Up @@ -22,7 +22,7 @@ class AESDecrypt extends Operation {

this.name = "AES Decrypt";
this.module = "Ciphers";
this.description = "Advanced Encryption Standard (AES) is a U.S. Federal Information Processing Standard (FIPS). It was selected after a 5-year process where 15 competing designs were evaluated.<br><br><b>Key:</b> The following algorithms will be used based on the size of the key:<ul><li>16 bytes = AES-128</li><li>24 bytes = AES-192</li><li>32 bytes = AES-256</li></ul><br><br><b>IV:</b> The Initialization Vector should be 16 bytes long. If not entered, it will default to 16 null bytes.<br><br><b>Padding:</b> In CBC and ECB mode, PKCS#7 padding will be used.<br><br><b>GCM Tag:</b> This field is ignored unless 'GCM' mode is used.";
this.description = "Advanced Encryption Standard (AES) is a U.S. Federal Information Processing Standard (FIPS). It was selected after a 5-year process where 15 competing designs were evaluated.<br><br><b>Key:</b> The following algorithms will be used based on the size of the key:<ul><li>16 bytes = AES-128</li><li>24 bytes = AES-192</li><li>32 bytes = AES-256</li></ul><br><br><b>IV:</b> The Initialization Vector should be 16 bytes long. If not entered, it will default to 16 null bytes.<br><br><b>Padding:</b> In CBC and ECB mode, PKCS#7 padding will be used as a default.<br><br><b>GCM Tag:</b> This field is ignored unless 'GCM' mode is used.";
this.infoURL = "https://wikipedia.org/wiki/Advanced_Encryption_Standard";
this.inputType = "string";
this.outputType = "string";
Expand Down Expand Up @@ -66,6 +66,14 @@ class AESDecrypt extends Operation {
{
name: "ECB",
off: [5, 6]
},
{
name: "CBC/NoPadding",
off: [5, 6]
},
{
name: "ECB/NoPadding",
off: [5, 6]
}
]
},
Expand Down Expand Up @@ -104,7 +112,7 @@ class AESDecrypt extends Operation {
run(input, args) {
const key = Utils.convertToByteString(args[0].string, args[0].option),
iv = Utils.convertToByteString(args[1].string, args[1].option),
mode = args[2],
mode = args[2].substring(0, 3),
inputType = args[3],
outputType = args[4],
gcmTag = Utils.convertToByteString(args[5].string, args[5].option),
Expand All @@ -122,6 +130,12 @@ The following algorithms will be used based on the size of the key:
input = Utils.convertToByteString(input, inputType);

const decipher = forge.cipher.createDecipher("AES-" + mode, key);
/* Allow for a "no padding" mode */
if (args[2].endsWith("NoPadding")) {
decipher.mode.unpad = function(output, options) {
return true;
};
}
decipher.start({
iv: iv.length === 0 ? "" : iv,
tag: mode === "GCM" ? gcmTag : undefined,
Expand Down
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