diff --git a/lib/csr-ec.js b/lib/csr-ec.js
new file mode 100644
index 0000000..72ee072
--- /dev/null
+++ b/lib/csr-ec.js
@@ -0,0 +1,157 @@
+// 1.2.840.10045.3.1.7
+// prime256v1 (ANSI X9.62 named elliptic curve)
+var OBJ_ID_EC  = '06 08 2A8648CE3D030107'.replace(/\s+/g, '').toLowerCase();
+// 1.3.132.0.34
+// secp384r1 (SECG (Certicom) named elliptic curve)
+var OBJ_ID_EC_384 = '06 05 2B81040022'.replace(/\s+/g, '').toLowerCase();
+
+var ECDSACSR = {};
+var ECDSA = {};
+var DER = {};
+var PEM = {};
+var ASN1;
+var Hex = {};
+var AB = {};
+
+//
+// CSR - the main event
+//
+
+ECDSACSR.create = function createEcCsr(keypem, domains) {
+  var pemblock = PEM.parseBlock(keypem);
+  var ecpub = PEM.parseEcPubkey(pemblock.der);
+  var request = ECDSACSR.request(ecpub, domains);
+  return AB.fromHex(ECDSACSR.sign(keypem, request));
+};
+
+ECDSACSR.request = function createCsrBodyEc(xy, domains) {
+  var publen = xy.x.byteLength;
+  var compression = '04';
+  var hxy = '';
+  // 04 == x+y, 02 == x-only
+  if (xy.y) {
+    publen += xy.y.byteLength;
+  } else {
+    // Note: I don't intend to support compression - it isn't used by most
+    // libraries and it requir more dependencies for bigint ops to deflate.
+    // This is more just a placeholder. It won't work right now anyway
+    // because compression requires an exta bit stored (odd vs even), which
+    // I haven't learned yet, and I'm not sure if it's allowed at all
+    compression = '02';
+  }
+  hxy += Hex.fromAB(xy.x);
+  if (xy.y) { hxy += Hex.fromAB(xy.y); }
+
+  // Sorry for the mess, but it is what it is
+  return ASN1('30'
+
+      // Version (0)
+    , ASN1.UInt('00')
+
+      // CN / Subject
+    , ASN1('30'
+      , ASN1('31'
+        , ASN1('30'
+            // object id (commonName)
+          , ASN1('06', '55 04 03')
+          , ASN1('0C', Hex.fromString(domains[0])))))
+
+      // EC P-256 Public Key
+    , ASN1('30'
+      , ASN1('30'
+          // 1.2.840.10045.2.1 ecPublicKey
+          // (ANSI X9.62 public key type)
+        , ASN1('06', '2A 86 48 CE 3D 02 01')
+          // 1.2.840.10045.3.1.7 prime256v1
+          // (ANSI X9.62 named elliptic curve)
+        , ASN1('06', '2A 86 48 CE 3D 03 01 07')
+        )
+      , ASN1.BitStr(compression + hxy))
+
+      // CSR Extension Subject Alternative Names
+    , ASN1('A0'
+      , ASN1('30'
+          // (extensionRequest (PKCS #9 via CRMF))
+        , ASN1('06', '2A 86 48 86 F7 0D 01 09 0E')
+        , ASN1('31'
+          , ASN1('30'
+            , ASN1('30'
+                // (subjectAltName (X.509 extension))
+              , ASN1('06', '55 1D 11')
+              , ASN1('04'
+                , ASN1('30', domains.map(function (d) {
+                    return ASN1('82', Hex.fromString(d));
+                  }).join(''))))))))
+  );
+};
+
+ECDSACSR.sign = function csrEcSig(keypem, request) {
+  var sig = ECDSA.sign(keypem, AB.fromHex(request));
+  var rLen = sig.r.byteLength;
+  var rc = '';
+  var sLen = sig.s.byteLength;
+  var sc = '';
+
+  if (0x80 & new Uint8Array(sig.r)[0]) { rc = '00'; rLen += 1; }
+  if (0x80 & new Uint8Array(sig.s)[0]) { sc = '00'; sLen += 1; }
+
+  return ASN1('30'
+      // The Full CSR Request Body
+    , request
+
+      // The Signature Type
+    , ASN1('30'
+        // 1.2.840.10045.4.3.2 ecdsaWithSHA256
+        // (ANSI X9.62 ECDSA algorithm with SHA256)
+      , ASN1('06', '2A 86 48 CE 3D 04 03 02')
+      )
+
+      // The Signature, embedded in a Bit Stream
+    , ASN1.BitStr(
+        // As far as I can tell this is a completely separate ASN.1 structure
+        // that just so happens to be embedded in a Bit String of another ASN.1
+        ASN1('30'
+        , ASN1.UInt(Hex.fromAB(sig.r))
+        , ASN1.UInt(Hex.fromAB(sig.s))))
+  );
+};
+
+//
+// ECDSA
+//
+
+// Took some tips from https://gist.github.com/codermapuche/da4f96cdb6d5ff53b7ebc156ec46a10a
+ECDSA.sign = function signEc(keypem, ab) {
+  // Signer is a stream
+  var sign = crypto.createSign('SHA256');
+  sign.write(new Uint8Array(ab));
+  sign.end();
+
+  // The signature is ASN1 encoded
+  var sig = sign.sign(keypem);
+
+  // Convert to a JavaScript ArrayBuffer just because
+  sig = new Uint8Array(sig.buffer.slice(sig.byteOffset, sig.byteOffset + sig.byteLength));
+
+  // The first two bytes '30 xx' signify SEQUENCE and LENGTH
+  // The sequence length byte will be a single byte because the signature is less that 128 bytes (0x80, 1024-bit)
+  // (this would not be true for P-521, but I'm not supporting that yet)
+  // The 3rd byte will be '02', signifying INTEGER
+  // The 4th byte will tell us the length of 'r' (which, on occassion, will be less than the full 255 bytes)
+  var rIndex = 3;
+  var rLen = sig[rIndex];
+  var rEnd = rIndex + 1 + rLen;
+  var sIndex = rEnd + 1;
+  var sLen = sig[sIndex];
+  var sEnd = sIndex + 1 + sLen;
+  var r = sig.slice(rIndex + 1, rEnd);
+  var s = sig.slice(sIndex + 1, sEnd); // this should be end-of-file
+
+  // ASN1 INTEGER types use the high-order bit to signify a negative number,
+  // hence a leading '00' is used for numbers that begin with '80' or greater
+  // which is why r length is sometimes a byte longer than its bit length
+  if (0 === s[0]) { s = s.slice(1); }
+  if (0 === r[0]) { r = r.slice(1); }
+
+  return { raw: sig.buffer, r: r.buffer, s: s.buffer };
+};
diff --git a/lib/csr.js b/lib/csr.js
new file mode 100644
index 0000000..aab4763
--- /dev/null
+++ b/lib/csr.js
@@ -0,0 +1,213 @@
+'use strict';
+
+var crypto = require('crypto');
+var ASN1 = require('./asn1.js');
+var Enc = require('./encoding.js');
+var PEM = require('./pem.js');
+var X509 = require('./x509.js');
+var RSA = {};
+
+/*global Promise*/
+var CSR = module.exports = function rsacsr(opts) {
+  // We're using a Promise here to be compatible with the browser version
+  // which will probably use the webcrypto API for some of the conversions
+  opts = CSR._prepare(opts);
+
+  return CSR.create(opts).then(function (bytes) {
+    return CSR._encode(opts, bytes);
+  });
+};
+
+CSR._prepare = function (opts) {
+  var Rasha;
+  opts = JSON.parse(JSON.stringify(opts));
+  var pem, jwk;
+
+  // We do a bit of extra error checking for user convenience
+  if (!opts) { throw new Error("You must pass options with key and domains to rsacsr"); }
+  if (!Array.isArray(opts.domains) || 0 === opts.domains.length) {
+    new Error("You must pass options.domains as a non-empty array");
+  }
+
+  // I need to check that 例.中国 is a valid domain name
+  if (!opts.domains.every(function (d) {
+    // allow punycode? xn--
+    if ('string' === typeof d /*&& /\./.test(d) && !/--/.test(d)*/) {
+      return true;
+    }
+  })) {
+    throw new Error("You must pass options.domains as strings");
+  }
+
+  if (opts.pem) {
+    pem = opts.pem;
+  } else if (opts.jwk) {
+    jwk = opts.jwk;
+  } else {
+    if (!opts.key) {
+      throw new Error("You must pass options.key as a JSON web key");
+    } else if (opts.key.kty) {
+      jwk = opts.key;
+    } else {
+      pem = opts.key;
+    }
+  }
+
+  if (pem) {
+    try {
+      Rasha = require('rasha');
+    } catch(e) {
+      throw new Error("Rasha.js is an optional dependency for PEM-to-JWK.\n"
+        + "Install it if you'd like to use it:\n"
+        + "\tnpm install --save rasha\n"
+        + "Otherwise supply a jwk as the private key."
+      );
+    }
+    jwk = Rasha.importSync({ pem: pem });
+  }
+
+  opts.jwk = jwk;
+  return opts;
+};
+CSR.sync = function (opts) {
+  opts = CSR._prepare(opts);
+  var bytes = CSR.createSync(opts);
+  return CSR._encode(opts, bytes);
+};
+CSR._encode = function (opts, bytes) {
+  if ('der' === (opts.encoding||'').toLowerCase()) {
+    return bytes;
+  }
+  return PEM.packBlock({
+    type: "CERTIFICATE REQUEST"
+  , bytes: bytes /* { jwk: jwk, domains: opts.domains } */
+  });
+};
+
+CSR.createSync = function createCsr(opts) {
+  var hex = CSR.request(opts.jwk, opts.domains);
+  var csr = CSR.signSync(opts.jwk, hex);
+  return Enc.hexToBuf(csr);
+};
+CSR.create = function createCsr(opts) {
+  var hex = CSR.request(opts.jwk, opts.domains);
+  return CSR.sign(opts.jwk, hex).then(function (csr) {
+    return Enc.hexToBuf(csr);
+  });
+};
+
+CSR.request = function createCsrBodyEc(jwk, domains) {
+  var asn1pub = X509.packCsrPublicKey(jwk);
+  return X509.packCsr(asn1pub, domains);
+};
+
+CSR.signSync = function csrEcSig(jwk, request) {
+  var keypem = PEM.packBlock({ type: "RSA PRIVATE KEY", bytes: X509.packPkcs1(jwk) });
+  var sig = RSA.signSync(keypem, Enc.hexToBuf(request));
+  return CSR.toDer({ request: request, signature: sig });
+};
+CSR.sign = function csrEcSig(jwk, request) {
+  var keypem = PEM.packBlock({ type: "RSA PRIVATE KEY", bytes: X509.packPkcs1(jwk) });
+  return RSA.sign(keypem, Enc.hexToBuf(request)).then(function (sig) {
+    return CSR.toDer({ request: request, signature: sig });
+  });
+};
+CSR.toDer = function encode(opts) {
+  var sty = ASN1('30'
+    // 1.2.840.113549.1.1.11 sha256WithRSAEncryption (PKCS #1)
+  , ASN1('06', '2a864886f70d01010b')
+  , ASN1('05')
+  );
+  return ASN1('30'
+    // The Full CSR Request Body
+  , opts.request
+    // The Signature Type
+  , sty
+    // The Signature
+  , ASN1.BitStr(Enc.bufToHex(opts.signature))
+  );
+};
+
+//
+// RSA
+//
+
+// Took some tips from https://gist.github.com/codermapuche/da4f96cdb6d5ff53b7ebc156ec46a10a
+RSA.signSync = function signRsaSync(keypem, ab) {
+  // Signer is a stream
+  var sign = crypto.createSign('SHA256');
+  sign.write(new Uint8Array(ab));
+  sign.end();
+
+  // The signature is ASN1 encoded, as it turns out
+  var sig = sign.sign(keypem);
+
+  // Convert to a JavaScript ArrayBuffer just because
+  return new Uint8Array(sig.buffer.slice(sig.byteOffset, sig.byteOffset + sig.byteLength));
+};
+RSA.sign = function signRsa(keypem, ab) {
+  return Promise.resolve().then(function () {
+    return RSA.signSync(keypem, ab);
+  });
+};
+
+
+X509.packCsrRsa = function (asn1pubkey, domains) {
+  return ASN1('30'
+    // Version (0)
+  , ASN1.UInt('00')
+
+    // 2.5.4.3 commonName (X.520 DN component)
+  , ASN1('30', ASN1('31', ASN1('30', ASN1('06', '550403'), ASN1('0c', Enc.utf8ToHex(domains[0])))))
+
+    // Public Key (RSA or EC)
+  , asn1pubkey
+
+    // Request Body
+  , ASN1('a0'
+    , ASN1('30'
+        // 1.2.840.113549.1.9.14 extensionRequest (PKCS #9 via CRMF)
+      , ASN1('06', '2a864886f70d01090e')
+      , ASN1('31'
+        , ASN1('30'
+          , ASN1('30'
+              // 2.5.29.17 subjectAltName (X.509 extension)
+            , ASN1('06', '551d11')
+            , ASN1('04'
+              , ASN1('30', domains.map(function (d) {
+                  return ASN1('82', Enc.utf8ToHex(d));
+                }).join(''))))))))
+  );
+};
+
+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.packCsrRsaPublicKey = function (jwk) {
+  // Sequence the key
+  var n = ASN1.UInt(Enc.base64ToHex(jwk.n));
+  var e = ASN1.UInt(Enc.base64ToHex(jwk.e));
+  var asn1pub = ASN1('30', n, e);
+  //var asn1pub = X509.packPkcs1({ kty: jwk.kty, n: jwk.n, e: jwk.e });
+
+  // Add the CSR pub key header
+  return ASN1('30', ASN1('30', ASN1('06', '2a864886f70d010101'), ASN1('05')), ASN1.BitStr(asn1pub));
+};