1 files changed, 47 insertions, 0 deletions
diff --git a/ext/node/polyfills/_crypto/crypto_browserify/browserify_rsa.js b/ext/node/polyfills/_crypto/crypto_browserify/browserify_rsa.js
new file mode 100644
index 000000000..b158462b8
--- /dev/null
+++ b/ext/node/polyfills/_crypto/crypto_browserify/browserify_rsa.js
@@ -0,0 +1,47 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// Copyright 2017 crypto-browserify. All rights reserved. MIT license.
+
+import { BN } from "internal:deno_node/polyfills/_crypto/crypto_browserify/bn.js/bn.js";
+import { randomBytes } from "internal:deno_node/polyfills/_crypto/crypto_browserify/randombytes.ts";
+import { Buffer } from "internal:deno_node/polyfills/buffer.ts";
+
+function blind(priv) {
+  const r = getr(priv);
+  const blinder = r.toRed(BN.mont(priv.modulus)).redPow(
+    new BN(priv.publicExponent),
+  ).fromRed();
+  return { blinder: blinder, unblinder: r.invm(priv.modulus) };
+}
+
+function getr(priv) {
+  const len = priv.modulus.byteLength();
+  let r;
+  do {
+    r = new BN(randomBytes(len));
+  } while (
+    r.cmp(priv.modulus) >= 0 || !r.umod(priv.prime1) || !r.umod(priv.prime2)
+  );
+  return r;
+}
+
+function crt(msg, priv) {
+  const blinds = blind(priv);
+  const len = priv.modulus.byteLength();
+  const blinded = new BN(msg).mul(blinds.blinder).umod(priv.modulus);
+  const c1 = blinded.toRed(BN.mont(priv.prime1));
+  const c2 = blinded.toRed(BN.mont(priv.prime2));
+  const qinv = priv.coefficient;
+  const p = priv.prime1;
+  const q = priv.prime2;
+  const m1 = c1.redPow(priv.exponent1).fromRed();
+  const m2 = c2.redPow(priv.exponent2).fromRed();
+  const h = m1.isub(m2).imul(qinv).umod(p).imul(q);
+  return m2.iadd(h).imul(blinds.unblinder).umod(priv.modulus).toArrayLike(
+    Buffer,
+    "be",
+    len,
+  );
+}
+crt.getr = getr;
+
+export default crt;