diff --git a/lib/generate-privkey-forge.js b/lib/generate-privkey-forge.js
new file mode 100644
index 0000000..686466f
--- /dev/null
+++ b/lib/generate-privkey-forge.js
@@ -0,0 +1,41 @@
+'use strict';
+
+var Rasha = require('rasha');
+
+module.exports = function (bitlen, exp) {
+  var k = require('node-forge').pki.rsa
+    .generateKeyPair({ bits: bitlen || 2048, e: exp || 0x10001 }).privateKey;
+  return Rasha.exportSync({
+    jwk: {
+      kty: "RSA"
+    , n: _toUrlBase64(k.n)
+    , e: _toUrlBase64(k.e)
+    , d: _toUrlBase64(k.d)
+    , p: _toUrlBase64(k.p)
+    , q: _toUrlBase64(k.q)
+    , dp: _toUrlBase64(k.dP)
+    , dq: _toUrlBase64(k.dQ)
+    , qi: _toUrlBase64(k.qInv)
+    }
+  });
+};
+
+function _toUrlBase64(fbn) {
+  var hex = fbn.toRadix(16);
+  if (hex.length % 2) {
+    // Invalid hex string
+    hex = '0' + hex;
+  }
+  while ('00' === hex.slice(0, 2)) {
+    hex = hex.slice(2);
+  }
+  return Buffer.from(hex, 'hex').toString('base64')
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=/g,"")
+  ;
+}
+
+if (require.main === module) {
+  console.log(module.exports(2048, 0x10001));
+}
diff --git a/lib/generate-privkey-node.js b/lib/generate-privkey-node.js
new file mode 100644
index 0000000..0a2ff88
--- /dev/null
+++ b/lib/generate-privkey-node.js
@@ -0,0 +1,22 @@
+'use strict';
+
+module.exports = function (bitlen, exp) {
+  return require('crypto').generateKeyPairSync(
+    'rsa'
+  , { modulusLength: bitlen
+    , publicExponent: exp
+    , privateKeyEncoding: {
+        type: 'pkcs8'
+      , format: 'pem'
+      }
+    , publicKeyEncoding: {
+        type: 'spki'
+      , format: 'pem'
+      }
+    }
+  ).privateKey.trim();
+};
+
+if (require.main === module) {
+  console.log(module.exports(2048, 0x10001));
+}
diff --git a/lib/generate-privkey-ursa.js b/lib/generate-privkey-ursa.js
new file mode 100644
index 0000000..4fbb501
--- /dev/null
+++ b/lib/generate-privkey-ursa.js
@@ -0,0 +1,9 @@
+'use strict';
+
+module.exports = function (bitlen, exp) {
+  return require('ursa').generatePrivateKey(bitlen || 2048, exp || 65537).toPrivatePem().toString('ascii').trim();
+};
+
+if (require.main === module) {
+  console.log(module.exports(2048, 0x10001));
+}
diff --git a/lib/generate-privkey.js b/lib/generate-privkey.js
new file mode 100644
index 0000000..afeb484
--- /dev/null
+++ b/lib/generate-privkey.js
@@ -0,0 +1,42 @@
+'use strict';
+
+var oldver = false;
+
+module.exports = function (bitlen, exp) {
+  bitlen = parseInt(bitlen, 10);
+  exp = parseInt(exp, 10);
+
+  try {
+    return require('./generate-privkey-node')(bitlen, exp);
+  } catch(e) {
+    if (!/generateKeyPairSync is not a function/.test(e.message)) {
+      throw e;
+    }
+    try {
+      return require('./generate-privkey-ursa')(bitlen, exp);
+    } catch(e) {
+      if (e.code !== 'MODULE_NOT_FOUND') {
+        throw e;
+      }
+      if (!oldver) {
+        oldver = true;
+        console.warn("[WARN] rsa-compat: Your version of node does not have crypto.generateKeyPair()");
+        console.warn("[WARN] rsa-compat: Please update to node >= v10.12 or 'npm install ursa'");
+        console.warn("[WARN] rsa-compat: Using node-forge as a fallback, but it may be unacceptably slow.");
+      }
+      try {
+        return require('./generate-privkey-forge')(bitlen, exp);
+      } catch(e) {
+        if (e.code !== 'MODULE_NOT_FOUND') {
+          throw e;
+        }
+        console.error("[ERROR] rsa-compat: could not generate a private key.");
+        console.error("None of crypto.generateKeyPair, ursa, nor node-forge are present");
+      }
+    }
+  }
+};
+
+if (require.main === module) {
+  console.log(module.exports(2048, 0x10001));
+}