diff --git a/src/ursaNative.cc b/src/ursaNative.cc
index 003b604..16fab4a 100644
--- a/src/ursaNative.cc
+++ b/src/ursaNative.cc
@@ -410,7 +410,11 @@ Handle<Value> RsaWrap::GetPublicKeyPem(const Arguments& args) {
     return bioToBuffer(bio);
 }
 
-// FIXME: Need documentation.
+/**
+ * Perform decryption on the given buffer using the RSA key, which
+ * must be a private key. This always uses the padding mode
+ * RSA_PKCS1_OAEP_PADDING.
+ */
 Handle<Value> RsaWrap::PrivateDecrypt(const Arguments& args) {
     HandleScope scope;
 
@@ -421,8 +425,26 @@ Handle<Value> RsaWrap::PrivateDecrypt(const Arguments& args) {
     void *data = getArg0DataAndLength(args, &length);
     if (data == NULL) { return Undefined(); }
 
-    // FIXME: Need real implementation.
-    return scope.Close(String::New("world"));
+    int rsaLength = RSA_size(obj->rsa);
+    unsigned char buf[rsaLength];
+
+    int bufLength = RSA_private_decrypt(length, (unsigned char *) data,
+                                        buf, obj->rsa, RSA_PKCS1_OAEP_PADDING);
+
+    if (bufLength < 0) {
+        scheduleSslException();
+        return Undefined();
+    }
+
+    node::Buffer *result = node::Buffer::New(bufLength);
+
+    if (result == NULL) {
+        scheduleAllocException();
+        return Undefined();
+    }
+
+    memcpy(node::Buffer::Data(result), buf, bufLength);
+    return result->handle_;
 }
 
 // FIXME: Need documentation.
diff --git a/test/fixture.js b/test/fixture.js
index 87ad7ef..5f463c1 100644
--- a/test/fixture.js
+++ b/test/fixture.js
@@ -41,7 +41,15 @@ var MODULUS_HEX =
     "cfa70934d1c7b9e2e5a3c1897fb10f803af2998495db24511f2b2162f1fd8475";
 
 var PLAINTEXT = "Muffins are tasty.";
-var PRIVATE_CIPHERTEXT_HEX = "1234"; // FIXME
+var PRIVATE_CIPHERTEXT_HEX =
+    "98a96084dc8dfad2c4e604dc20def71acbf784b8b34ecafeb2840e238ac8031c" +
+    "7559004fa8337d20889b8a582af4f7d3707ab41d0a81487f0d80fb82be49537c" +
+    "2b9cd8dbb3b772fe0306ff9b4b99faa7cc26d5c04b1e8e79505bac1e8f2cdad2" +
+    "d3d8680eee3c16db8742b61935fca9679070d278f988ce4d414ab49a544c9088" +
+    "17a0d340a41384f4b8d826e41031ddcd3f72c29dec2fee0355a8203ea0d381a1" +
+    "a0f0969804d4968fb2e6220db5cf02e2c2200ff9d0a5a5037ac859a55c005ecc" +
+    "52ce194a6a9624c71547c96cf90d911caa4097f9cdfded71d23c9f8f5551188c" +
+    "8326357d54224ab25b9f29c1efdbc960a0968e4c9027cd507ffadd8dff93256c";
 var PUBLIC_CIPHERTEXT_HEX = "1234"; // FIXME
 
 /*
diff --git a/test/native.js b/test/native.js
index 6977476..4d2f024 100644
--- a/test/native.js
+++ b/test/native.js
@@ -216,28 +216,28 @@ function test_fail_privateDecrypt() {
     function f2() {
         rsa.privateDecrypt("x");
     }
-    assert.throws(f2, /arg mumble FIXME/);
+    assert.throws(f2, /Expected a Buffer in args\[0]\./);
 
     function f3() {
         rsa.privateDecrypt(new Buffer("x"));
     }
-    assert.throws(f3, /mumble FIXME/);
+    assert.throws(f3, /decoding error/);
 }
 
 function test_publicEncrypt() {
     // No other reasonable way to test this than to do a round trip.
     var plainBuf = new Buffer(fixture.PLAINTEXT, fixture.UTF8);
+    var priv = new RsaWrap();
+    priv.setPrivateKeyPem(fixture.PRIVATE_KEY);
 
     var rsa = new RsaWrap();
     rsa.setPublicKeyPem(fixture.PUBLIC_KEY);
     var encoded = rsa.publicEncrypt(plainBuf);
-    var decoded = rsa.privateDecrypt(encoded).toString(fixture.UTF8);
+    var decoded = priv.privateDecrypt(encoded).toString(fixture.UTF8);
     assert.equal(decoded, fixture.PLAINTEXT);
 
-    rsa = new RsaWrap();
-    rsa.setPrivateKeyPem(fixture.PRIVATE_KEY);
-    encoded = rsa.publicEncrypt(plainBuf);
-    decoded = rsa.privateDecrypt(encoded).toString(fixture.UTF8);
+    encoded = priv.publicEncrypt(plainBuf);
+    decoded = priv.privateDecrypt(encoded).toString(fixture.UTF8);
     assert.equal(decoded, fixture.PLAINTEXT);
 }
 
@@ -286,6 +286,8 @@ function test() {
     test_getPublicKeyPem();
     test_fail_getPublicKeyPem();
 
+    test_publicEncrypt(); // remove!
+
     test_privateDecrypt();
     test_fail_privateDecrypt();
     test_publicEncrypt();