//引用 https://github.com/video-dev/hls.js
function removePadding(buffer) {
const outputBytes = buffer.byteLength;
const paddingBytes = outputBytes && (new DataView(buffer)).getUint8(outputBytes - 1);
if (paddingBytes) {
return buffer.slice(0, outputBytes - paddingBytes);
} else {
return buffer;
}
}
function AESDecryptor() {
return {
constructor() {
this.rcon = [0x0, 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36];
this.subMix = [new Uint32Array(256), new Uint32Array(256), new Uint32Array(256), new Uint32Array(256)];
this.invSubMix = [new Uint32Array(256), new Uint32Array(256), new Uint32Array(256), new Uint32Array(256)];
this.sBox = new Uint32Array(256);
this.invSBox = new Uint32Array(256);
// Changes during runtime
this.key = new Uint32Array(0);
this.initTable();
},
// Using view.getUint32() also swaps the byte order.
uint8ArrayToUint32Array_(arrayBuffer) {
let view = new DataView(arrayBuffer);
let newArray = new Uint32Array(4);
for (let i = 0; i < 4; i++) {
newArray[i] = view.getUint32(i * 4);
}
return newArray;
},
initTable() {
let sBox = this.sBox;
let invSBox = this.invSBox;
let subMix = this.subMix;
let subMix0 = subMix[0];
let subMix1 = subMix[1];
let subMix2 = subMix[2];
let subMix3 = subMix[3];
let invSubMix = this.invSubMix;
let invSubMix0 = invSubMix[0];
let invSubMix1 = invSubMix[1];
let invSubMix2 = invSubMix[2];
let invSubMix3 = invSubMix[3];
let d = new Uint32Array(256);
let x = 0;
let xi = 0;
let i = 0;
for (i = 0; i < 256; i++) {
if (i < 128) {
d[i] = i << 1;
} else {
d[i] = (i << 1) ^ 0x11b;
}
}
for (i = 0; i < 256; i++) {
let sx = xi ^ (xi << 1) ^ (xi << 2) ^ (xi << 3) ^ (xi << 4);
sx = (sx >>> 8) ^ (sx & 0xff) ^ 0x63;
sBox[x] = sx;
invSBox[sx] = x;
// Compute multiplication
let x2 = d[x];
let x4 = d[x2];
let x8 = d[x4];
// Compute sub/invSub bytes, mix columns tables
let t = (d[sx] * 0x101) ^ (sx * 0x1010100);
subMix0[x] = (t << 24) | (t >>> 8);
subMix1[x] = (t << 16) | (t >>> 16);
subMix2[x] = (t << 8) | (t >>> 24);
subMix3[x] = t;
// Compute inv sub bytes, inv mix columns tables
t = (x8 * 0x1010101) ^ (x4 * 0x10001) ^ (x2 * 0x101) ^ (x * 0x1010100);
invSubMix0[sx] = (t << 24) | (t >>> 8);
invSubMix1[sx] = (t << 16) | (t >>> 16);
invSubMix2[sx] = (t << 8) | (t >>> 24);
invSubMix3[sx] = t;
// Compute next counter
if (!x) {
x = xi = 1;
} else {
x = x2 ^ d[d[d[x8 ^ x2]]];
xi ^= d[d[xi]];
}
}
},
expandKey(keyBuffer) {
// convert keyBuffer to Uint32Array
let key = this.uint8ArrayToUint32Array_(keyBuffer);
let sameKey = true;
let offset = 0;
while (offset < key.length && sameKey) {
sameKey = (key[offset] === this.key[offset]);
offset++;
}
if (sameKey) {
return;
}
this.key = key;
let keySize = this.keySize = key.length;
if (keySize !== 4 && keySize !== 6 && keySize !== 8) {
throw new Error('Invalid aes key size=' + keySize);
}
let ksRows = this.ksRows = (keySize + 6 + 1) * 4;
let ksRow;
let invKsRow;
let keySchedule = this.keySchedule = new Uint32Array(ksRows);
let invKeySchedule = this.invKeySchedule = new Uint32Array(ksRows);
let sbox = this.sBox;
let rcon = this.rcon;
let invSubMix = this.invSubMix;
let invSubMix0 = invSubMix[0];
let invSubMix1 = invSubMix[1];
let invSubMix2 = invSubMix[2];
let invSubMix3 = invSubMix[3];
let prev;
let t;
for (ksRow = 0; ksRow < ksRows; ksRow++) {
if (ksRow < keySize) {
prev = keySchedule[ksRow] = key[ksRow];
continue;
}
t = prev;
if (ksRow % keySize === 0) {
// Rot word
t = (t << 8) | (t >>> 24);
// Sub word
t = (sbox[t >>> 24] << 24) | (sbox[(t >>> 16) & 0xff] << 16) | (sbox[(t >>> 8) & 0xff] << 8) | sbox[t & 0xff];
// Mix Rcon
t ^= rcon[(ksRow / keySize) | 0] << 24;
} else if (keySize > 6 && ksRow % keySize === 4) {
// Sub word
t = (sbox[t >>> 24] << 24) | (sbox[(t >>> 16) & 0xff] << 16) | (sbox[(t >>> 8) & 0xff] << 8) | sbox[t & 0xff];
}
keySchedule[ksRow] = prev = (keySchedule[ksRow - keySize] ^ t) >>> 0;
}
for (invKsRow = 0; invKsRow < ksRows; invKsRow++) {
ksRow = ksRows - invKsRow;
if (invKsRow & 3) {
t = keySchedule[ksRow];
} else {
t = keySchedule[ksRow - 4];
}
if (invKsRow < 4 || ksRow <= 4) {
invKeySchedule[invKsRow] = t;
} else {
invKeySchedule[invKsRow] = invSubMix0[sbox[t >>> 24]] ^ invSubMix1[sbox[(t >>> 16) & 0xff]] ^ invSubMix2[sbox[(t >>> 8) & 0xff]] ^ invSubMix3[sbox[t & 0xff]];
}
invKeySchedule[invKsRow] = invKeySchedule[invKsRow] >>> 0;
}
},
// Adding this as a method greatly improves performance.
networkToHostOrderSwap(word) {
return (word << 24) | ((word & 0xff00) << 8) | ((word & 0xff0000) >> 8) | (word >>> 24);
},
decrypt(inputArrayBuffer, offset, aesIV, removePKCS7Padding) {
let nRounds = this.keySize + 6;
let invKeySchedule = this.invKeySchedule;
let invSBOX = this.invSBox;
let invSubMix = this.invSubMix;
let invSubMix0 = invSubMix[0];
let invSubMix1 = invSubMix[1];
let invSubMix2 = invSubMix[2];
let invSubMix3 = invSubMix[3];
let initVector = this.uint8ArrayToUint32Array_(aesIV);
let initVector0 = initVector[0];
let initVector1 = initVector[1];
let initVector2 = initVector[2];
let initVector3 = initVector[3];
let inputInt32 = new Int32Array(inputArrayBuffer);
let outputInt32 = new Int32Array(inputInt32.length);
let t0, t1, t2, t3;
let s0, s1, s2, s3;
let inputWords0, inputWords1, inputWords2, inputWords3;
let ksRow, i;
let swapWord = this.networkToHostOrderSwap;
while (offset < inputInt32.length) {
inputWords0 = swapWord(inputInt32[offset]);
inputWords1 = swapWord(inputInt32[offset + 1]);
inputWords2 = swapWord(inputInt32[offset + 2]);
inputWords3 = swapWord(inputInt32[offset + 3]);
s0 = inputWords0 ^ invKeySchedule[0];
s1 = inputWords3 ^ invKeySchedule[1];
s2 = inputWords2 ^ invKeySchedule[2];
s3 = inputWords1 ^ invKeySchedule[3];
ksRow = 4;
// Iterate through the rounds of decryption
for (i = 1; i < nRounds; i++) {
t0 = invSubMix0[s0 >>> 24] ^ invSubMix1[(s1 >> 16) & 0xff] ^ invSubMix2[(s2 >> 8) & 0xff] ^ invSubMix3[s3 & 0xff] ^ invKeySchedule[ksRow];
t1 = invSubMix0[s1 >>> 24] ^ invSubMix1[(s2 >> 16) & 0xff] ^ invSubMix2[(s3 >> 8) & 0xff] ^ invSubMix3[s0 & 0xff] ^ invKeySchedule[ksRow + 1];
t2 = invSubMix0[s2 >>> 24] ^ invSubMix1[(s3 >> 16) & 0xff] ^ invSubMix2[(s0 >> 8) & 0xff] ^ invSubMix3[s1 & 0xff] ^ invKeySchedule[ksRow + 2];
t3 = invSubMix0[s3 >>> 24] ^ invSubMix1[(s0 >> 16) & 0xff] ^ invSubMix2[(s1 >> 8) & 0xff] ^ invSubMix3[s2 & 0xff] ^ invKeySchedule[ksRow + 3];
// Update state
s0 = t0;
s1 = t1;
s2 = t2;
s3 = t3;
ksRow = ksRow + 4;
}
// Shift rows, sub bytes, add round key
t0 = ((invSBOX[s0 >>> 24] << 24) ^ (invSBOX[(s1 >> 16) & 0xff] << 16) ^ (invSBOX[(s2 >> 8) & 0xff] << 8) ^ invSBOX[s3 & 0xff]) ^ invKeySchedule[ksRow];
t1 = ((invSBOX[s1 >>> 24] << 24) ^ (invSBOX[(s2 >> 16) & 0xff] << 16) ^ (invSBOX[(s3 >> 8) & 0xff] << 8) ^ invSBOX[s0 & 0xff]) ^ invKeySchedule[ksRow + 1];
t2 = ((invSBOX[s2 >>> 24] << 24) ^ (invSBOX[(s3 >> 16) & 0xff] << 16) ^ (invSBOX[(s0 >> 8) & 0xff] << 8) ^ invSBOX[s1 & 0xff]) ^ invKeySchedule[ksRow + 2];
t3 = ((invSBOX[s3 >>> 24] << 24) ^ (invSBOX[(s0 >> 16) & 0xff] << 16) ^ (invSBOX[(s1 >> 8) & 0xff] << 8) ^ invSBOX[s2 & 0xff]) ^ invKeySchedule[ksRow + 3];
ksRow = ksRow + 3;
// Write
outputInt32[offset] = swapWord(t0 ^ initVector0);
outputInt32[offset + 1] = swapWord(t3 ^ initVector1);
outputInt32[offset + 2] = swapWord(t2 ^ initVector2);
outputInt32[offset + 3] = swapWord(t1 ^ initVector3);
// reset initVector to last 4 unsigned int
initVector0 = inputWords0;
initVector1 = inputWords1;
initVector2 = inputWords2;
initVector3 = inputWords3;
offset = offset + 4;
}
return removePKCS7Padding ? removePadding(outputInt32.buffer) : outputInt32.buffer;
},
destroy() {
this.key = undefined;
this.keySize = undefined;
this.ksRows = undefined;
this.sBox = undefined;
this.invSBox = undefined;
this.subMix = undefined;
this.invSubMix = undefined;
this.keySchedule = undefined;
this.invKeySchedule = undefined;
this.rcon = undefined;
},
}
}