支持朋友圈图片解密；视频解密；实况渲染

2026-03-25 15:25:50 +00:00 · 2026-02-16 23:31:52 +08:00
parent 75b056d5ba
commit b4248d4a12
21 changed files with 5748 additions and 225 deletions
--- a/electron/services/isaac64.ts
+++ b/electron/services/isaac64.ts
@@ -0,0 +1,121 @@
+/**
+ * ISAAC-64: A fast cryptographic PRNG
+ * Re-implemented in TypeScript using BigInt for 64-bit support.
+ * Used for WeChat Channels/SNS video decryption.
+ */
+
+export class Isaac64 {
+    private mm = new BigUint64Array(256);
+    private aa = 0n;
+    private bb = 0n;
+    private cc = 0n;
+    private randrsl = new BigUint64Array(256);
+    private randcnt = 0;
+    private static readonly MASK = 0xFFFFFFFFFFFFFFFFn;
+
+    constructor(seed: number | string | bigint) {
+        const seedBig = BigInt(seed);
+        // 通常单密钥初始化是将密钥放在第一个槽位，其余清零（或者按某种规律填充）
+        // 这里我们尝试仅设置第一个槽位，这在很多 WASM 移植版本中更为常见
+        this.randrsl.fill(0n);
+        this.randrsl[0] = seedBig;
+        this.init(true);
+    }
+
+    private init(flag: boolean) {
+        let a: bigint, b: bigint, c: bigint, d: bigint, e: bigint, f: bigint, g: bigint, h: bigint;
+        a = b = c = d = e = f = g = h = 0x9e3779b97f4a7c15n;
+
+        const mix = () => {
+            a = (a - e) & Isaac64.MASK; f ^= (h >> 9n); h = (h + a) & Isaac64.MASK;
+            b = (b - f) & Isaac64.MASK; g ^= (a << 9n) & Isaac64.MASK; a = (a + b) & Isaac64.MASK;
+            c = (c - g) & Isaac64.MASK; h ^= (b >> 23n); b = (b + c) & Isaac64.MASK;
+            d = (d - h) & Isaac64.MASK; a ^= (c << 15n) & Isaac64.MASK; c = (c + d) & Isaac64.MASK;
+            e = (e - a) & Isaac64.MASK; b ^= (d >> 14n); d = (d + e) & Isaac64.MASK;
+            f = (f - b) & Isaac64.MASK; c ^= (e << 20n) & Isaac64.MASK; e = (e + f) & Isaac64.MASK;
+            g = (g - c) & Isaac64.MASK; d ^= (f >> 17n); f = (f + g) & Isaac64.MASK;
+            h = (h - d) & Isaac64.MASK; e ^= (g << 14n) & Isaac64.MASK; g = (g + h) & Isaac64.MASK;
+        };
+
+        for (let i = 0; i < 4; i++) mix();
+
+        for (let i = 0; i < 256; i += 8) {
+            if (flag) {
+                a = (a + this.randrsl[i]) & Isaac64.MASK;
+                b = (b + this.randrsl[i + 1]) & Isaac64.MASK;
+                c = (c + this.randrsl[i + 2]) & Isaac64.MASK;
+                d = (d + this.randrsl[i + 3]) & Isaac64.MASK;
+                e = (e + this.randrsl[i + 4]) & Isaac64.MASK;
+                f = (f + this.randrsl[i + 5]) & Isaac64.MASK;
+                g = (g + this.randrsl[i + 6]) & Isaac64.MASK;
+                h = (h + this.randrsl[i + 7]) & Isaac64.MASK;
+            }
+            mix();
+            this.mm[i] = a; this.mm[i + 1] = b; this.mm[i + 2] = c; this.mm[i + 3] = d;
+            this.mm[i + 4] = e; this.mm[i + 5] = f; this.mm[i + 6] = g; this.mm[i + 7] = h;
+        }
+
+        if (flag) {
+            for (let i = 0; i < 256; i += 8) {
+                a = (a + this.mm[i]) & Isaac64.MASK;
+                b = (b + this.mm[i + 1]) & Isaac64.MASK;
+                c = (c + this.mm[i + 2]) & Isaac64.MASK;
+                d = (d + this.mm[i + 3]) & Isaac64.MASK;
+                e = (e + this.mm[i + 4]) & Isaac64.MASK;
+                f = (f + this.mm[i + 5]) & Isaac64.MASK;
+                g = (g + this.mm[i + 6]) & Isaac64.MASK;
+                h = (h + this.mm[i + 7]) & Isaac64.MASK;
+                mix();
+                this.mm[i] = a; this.mm[i + 1] = b; this.mm[i + 2] = c; this.mm[i + 3] = d;
+                this.mm[i + 4] = e; this.mm[i + 5] = f; this.mm[i + 6] = g; this.mm[i + 7] = h;
+            }
+        }
+
+        this.isaac64();
+        this.randcnt = 256;
+    }
+
+    private isaac64() {
+        this.cc = (this.cc + 1n) & Isaac64.MASK;
+        this.bb = (this.bb + this.cc) & Isaac64.MASK;
+        for (let i = 0; i < 256; i++) {
+            let x = this.mm[i];
+            switch (i & 3) {
+                case 0: this.aa = (this.aa ^ (((this.aa << 21n) & Isaac64.MASK) ^ Isaac64.MASK)) & Isaac64.MASK; break;
+                case 1: this.aa = (this.aa ^ (this.aa >> 5n)) & Isaac64.MASK; break;
+                case 2: this.aa = (this.aa ^ ((this.aa << 12n) & Isaac64.MASK)) & Isaac64.MASK; break;
+                case 3: this.aa = (this.aa ^ (this.aa >> 33n)) & Isaac64.MASK; break;
+            }
+            this.aa = (this.mm[(i + 128) & 255] + this.aa) & Isaac64.MASK;
+            const y = (this.mm[Number(x >> 3n) & 255] + this.aa + this.bb) & Isaac64.MASK;
+            this.mm[i] = y;
+            this.bb = (this.mm[Number(y >> 11n) & 255] + x) & Isaac64.MASK;
+            this.randrsl[i] = this.bb;
+        }
+    }
+
+    public getNext(): bigint {
+        if (this.randcnt === 0) {
+            this.isaac64();
+            this.randcnt = 256;
+        }
+        return this.randrsl[256 - (this.randcnt--)];
+    }
+
+    /**
+     * Generates a keystream of the specified size (in bytes).
+     * @param size Size of the keystream in bytes (must be multiple of 8)
+     * @returns Buffer containing the keystream
+     */
+    public generateKeystream(size: number): Buffer {
+        const stream = new BigUint64Array(size / 8);
+        for (let i = 0; i < stream.length; i++) {
+            stream[i] = this.getNext();
+        }
+        // WeChat's logic specifically reverses the entire byte array
+        const buffer = Buffer.from(stream.buffer);
+        // 注意：根据 worker.html 的逻辑，它是对 Uint8Array 执行 reverse()
+        // Array.from(wasmArray).reverse()
+        return buffer.reverse();
+    }
+}