평문 환경 숙의 연습 해시 보정

apps/web/src/lib/sha256.ts

@@ -0,0 +1,116 @@
+const SHA256_INITIAL = new Uint32Array([
+  0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f,
+  0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
+]);
+
+const SHA256_ROUND = new Uint32Array([
+  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b,
+  0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01,
+  0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7,
+  0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
+  0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152,
+  0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+  0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc,
+  0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+  0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819,
+  0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08,
+  0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f,
+  0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+  0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
+]);
+
+function rotateRight(value: number, bits: number): number {
+  return (value >>> bits) | (value << (32 - bits));
+}
+
+function bytesToHex(bytes: Uint8Array): string {
+  return Array.from(bytes, (byte) => byte.toString(16).padStart(2, "0")).join(
+    "",
+  );
+}
+
+function portableSha256(bytes: Uint8Array): string {
+  const paddedLength = Math.ceil((bytes.length + 9) / 64) * 64;
+  const padded = new Uint8Array(paddedLength);
+  padded.set(bytes);
+  padded[bytes.length] = 0x80;
+
+  const view = new DataView(padded.buffer);
+  const bitLength = bytes.length * 8;
+  view.setUint32(paddedLength - 8, Math.floor(bitLength / 0x100000000));
+  view.setUint32(paddedLength - 4, bitLength >>> 0);
+
+  const state = new Uint32Array(SHA256_INITIAL);
+  const words = new Uint32Array(64);
+  for (let offset = 0; offset < paddedLength; offset += 64) {
+    for (let index = 0; index < 16; index += 1) {
+      words[index] = view.getUint32(offset + index * 4);
+    }
+    for (let index = 16; index < 64; index += 1) {
+      const previous = words[index - 15];
+      const recent = words[index - 2];
+      const sigma0 =
+        rotateRight(previous, 7) ^
+        rotateRight(previous, 18) ^
+        (previous >>> 3);
+      const sigma1 =
+        rotateRight(recent, 17) ^
+        rotateRight(recent, 19) ^
+        (recent >>> 10);
+      words[index] =
+        (words[index - 16] + sigma0 + words[index - 7] + sigma1) >>> 0;
+    }
+
+    let a = state[0];
+    let b = state[1];
+    let c = state[2];
+    let d = state[3];
+    let e = state[4];
+    let f = state[5];
+    let g = state[6];
+    let h = state[7];
+    for (let index = 0; index < 64; index += 1) {
+      const sum1 = rotateRight(e, 6) ^ rotateRight(e, 11) ^ rotateRight(e, 25);
+      const choose = (e & f) ^ (~e & g);
+      const temporary1 =
+        (h + sum1 + choose + SHA256_ROUND[index] + words[index]) >>> 0;
+      const sum0 = rotateRight(a, 2) ^ rotateRight(a, 13) ^ rotateRight(a, 22);
+      const majority = (a & b) ^ (a & c) ^ (b & c);
+      const temporary2 = (sum0 + majority) >>> 0;
+      h = g;
+      g = f;
+      f = e;
+      e = (d + temporary1) >>> 0;
+      d = c;
+      c = b;
+      b = a;
+      a = (temporary1 + temporary2) >>> 0;
+    }
+
+    state[0] = (state[0] + a) >>> 0;
+    state[1] = (state[1] + b) >>> 0;
+    state[2] = (state[2] + c) >>> 0;
+    state[3] = (state[3] + d) >>> 0;
+    state[4] = (state[4] + e) >>> 0;
+    state[5] = (state[5] + f) >>> 0;
+    state[6] = (state[6] + g) >>> 0;
+    state[7] = (state[7] + h) >>> 0;
+  }
+
+  return Array.from(state, (word) => word.toString(16).padStart(8, "0")).join(
+    "",
+  );
+}
+
+export async function sha256Hex(value: string): Promise<string> {
+  const bytes = new TextEncoder().encode(value);
+  const subtle = globalThis.crypto?.subtle;
+  if (subtle) {
+    try {
+      return bytesToHex(new Uint8Array(await subtle.digest("SHA-256", bytes)));
+    } catch {
+      // Some embedded or insecure runtimes expose Web Crypto partially.
+    }
+  }
+  return portableSha256(bytes);
+}