diff --git a/app.js b/app.js
index c56ea50..06c0022 100644
--- a/app.js
+++ b/app.js
@@ -45,17 +45,23 @@
       };
       console.log('opts', opts);
       Keypairs.generate(opts).then(function (results) {
+        var der;
         if (opts.kty == 'EC') {
-          var der = x509.packPkcs8(results.private);
+          der = x509.packPkcs8(results.private);
           var pem = Eckles.export({ jwk: results.private })
-          $('.js-der').innerText = JSON.stringify(der, null, 2);
           $('.js-input-pem').innerText = pem;
-          $('.js-toc-der').hidden = false;
           $('.js-toc-pem').hidden = false;
+        } else {
+          der = x509.packPkcs8(results.private);
+          var pem = Rasha.pack({ jwk: results.private }).then(function (pem) {
+            $('.js-input-pem').innerText = pem;
+            $('.js-toc-pem').hidden = false;
+          })
         }
 
+        $('.js-der').innerText = JSON.stringify(der, null, 2);
+        $('.js-toc-der').hidden = false;
         $('.js-jwk').innerText = JSON.stringify(results, null, 2);
-        //
         $('.js-loading').hidden = true;
         $('.js-jwk').hidden = false;
         $$('input').map(function ($el) { $el.disabled = false; });
diff --git a/lib/rsa.js b/lib/rsa.js
index 4ec7e07..17ceccb 100644
--- a/lib/rsa.js
+++ b/lib/rsa.js
@@ -3,6 +3,7 @@
 'use strict';
 
 var RSA = exports.Rasha = {};
+var x509 = exports.x509;
 if ('undefined' !== typeof module) { module.exports = RSA; }
 var Enc = {};
 var textEncoder = new TextEncoder();
@@ -106,6 +107,66 @@ RSA.thumbprint = function (opts) {
   });
 };
 
+RSA.export = function (opts) {
+  if (!opts || !opts.jwk || 'object' !== typeof opts.jwk) {
+    throw new Error("must pass { jwk: jwk }");
+  }
+  var jwk = JSON.parse(JSON.stringify(opts.jwk));
+  var format = opts.format;
+  var pub = opts.public;
+  if (pub || -1 !== [ 'spki', 'pkix', 'ssh', 'rfc4716' ].indexOf(format)) {
+    jwk = RSA.nueter(jwk);
+  }
+  if ('RSA' !== jwk.kty) {
+    throw new Error("options.jwk.kty must be 'RSA' for RSA keys");
+  }
+  if (!jwk.p) {
+    // TODO test for n and e
+    pub = true;
+    if (!format || 'pkcs1' === format) {
+      format = 'pkcs1';
+    } else if (-1 !== [ 'spki', 'pkix' ].indexOf(format)) {
+      format = 'spki';
+    } else if (-1 !== [ 'ssh', 'rfc4716' ].indexOf(format)) {
+      format = 'ssh';
+    } else {
+      throw new Error("options.format must be 'spki', 'pkcs1', or 'ssh' for public RSA keys, not ("
+        + typeof format + ") " + format);
+    }
+  } else {
+    // TODO test for all necessary keys (d, p, q ...)
+    if (!format || 'pkcs1' === format) {
+      format = 'pkcs1';
+    } else if ('pkcs8' !== format) {
+      throw new Error("options.format must be 'pkcs1' or 'pkcs8' for private RSA keys");
+    }
+  }
+
+  if ('pkcs1' === format) {
+    if (jwk.d) {
+      return PEM.packBlock({ type: "RSA PRIVATE KEY", bytes: x509.packPkcs1(jwk) });
+    } else {
+      return PEM.packBlock({ type: "RSA PUBLIC KEY", bytes: x509.packPkcs1(jwk) });
+    }
+  } else if ('pkcs8' === format) {
+    return PEM.packBlock({ type: "PRIVATE KEY", bytes: x509.packPkcs8(jwk) });
+  } else if (-1 !== [ 'spki', 'pkix' ].indexOf(format)) {
+    return PEM.packBlock({ type: "PUBLIC KEY", bytes: x509.packSpki(jwk) });
+  } else if (-1 !== [ 'ssh', 'rfc4716' ].indexOf(format)) {
+    return SSH.pack({ jwk: jwk, comment: opts.comment });
+  } else {
+    throw new Error("Sanity Error: reached unreachable code block with format: " + format);
+  }
+};
+RSA.pack = function (opts) {
+  // wrapped in a promise for API compatibility
+  // with the forthcoming browser version
+  // (and potential future native node capability)
+  return Promise.resolve().then(function () {
+    return RSA.export(opts);
+  });
+};
+
 Enc.bufToUrlBase64 = function (u8) {
   return Enc.bufToBase64(u8)
     .replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');
diff --git a/lib/x509.js b/lib/x509.js
index 3bf60fd..f1ac559 100644
--- a/lib/x509.js
+++ b/lib/x509.js
@@ -1,7 +1,7 @@
 'use strict';
 (function (exports) {
   'use strict';
-  var x509 = exports.x509 = {}; 
+  var x509 = exports.x509 = {};
   var ASN1 = exports.ASN1;
   var Enc = exports.Enc;
 
@@ -55,6 +55,27 @@
     };
   };
 
+  x509.packPkcs1 = function (jwk) {
+    var n = ASN1.UInt(Enc.base64ToHex(jwk.n));
+    var e = ASN1.UInt(Enc.base64ToHex(jwk.e));
+  
+    if (!jwk.d) {
+      return Enc.hexToBuf(ASN1('30', n, e));
+    }
+  
+    return Enc.hexToBuf(ASN1('30'
+    , ASN1.UInt('00')
+    , n
+    , e
+    , ASN1.UInt(Enc.base64ToHex(jwk.d))
+    , ASN1.UInt(Enc.base64ToHex(jwk.p))
+    , ASN1.UInt(Enc.base64ToHex(jwk.q))
+    , ASN1.UInt(Enc.base64ToHex(jwk.dp))
+    , ASN1.UInt(Enc.base64ToHex(jwk.dq))
+    , ASN1.UInt(Enc.base64ToHex(jwk.qi))
+    ));
+  };
+
   x509.parsePkcs8 = function parseEcPkcs8(u8, jwk) {
     var index = 24 + (OBJ_ID_EC.length / 2);
     var len = 32;
@@ -141,6 +162,44 @@
    * @param {*} jwk 
    */
   x509.packPkcs8 = function (jwk) {
+    if (jwk.kty == 'RSA') {
+      if (!jwk.d) {
+        // Public RSA
+        return Enc.hexToBuf(ASN1('30'
+          , ASN1('30'
+            , ASN1('06', '2a864886f70d010101')
+            , ASN1('05')
+          )
+          , ASN1.BitStr(ASN1('30'
+            , ASN1.UInt(Enc.base64ToHex(jwk.n))
+            , ASN1.UInt(Enc.base64ToHex(jwk.e))
+          ))
+        ));
+      }
+
+      // Private RSA
+      return Enc.hexToBuf(ASN1('30'
+        , ASN1.UInt('00')
+        , ASN1('30'
+          , ASN1('06', '2a864886f70d010101')
+          , ASN1('05')
+        )
+        , ASN1('04'
+          , ASN1('30'
+            , ASN1.UInt('00')
+            , ASN1.UInt(Enc.base64ToHex(jwk.n))
+            , ASN1.UInt(Enc.base64ToHex(jwk.e))
+            , ASN1.UInt(Enc.base64ToHex(jwk.d))
+            , ASN1.UInt(Enc.base64ToHex(jwk.p))
+            , ASN1.UInt(Enc.base64ToHex(jwk.q))
+            , ASN1.UInt(Enc.base64ToHex(jwk.dp))
+            , ASN1.UInt(Enc.base64ToHex(jwk.dq))
+            , ASN1.UInt(Enc.base64ToHex(jwk.qi))
+          )
+        )
+      ));
+    }
+
     var d = Enc.base64ToHex(jwk.d);
     var x = Enc.base64ToHex(jwk.x);
     var y = Enc.base64ToHex(jwk.y);