diff --git a/package.json b/package.json
index 1eaee39c41..e0cfb72148 100644
--- a/package.json
+++ b/package.json
@@ -67,6 +67,7 @@
     "react-dom": "^15.4.0",
     "react-gemini-scrollbar": "matrix-org/react-gemini-scrollbar#5e97aef",
     "sanitize-html": "^1.11.1",
+    "text-encoding-utf-8": "^1.0.1",
     "velocity-vector": "vector-im/velocity#059e3b2",
     "whatwg-fetch": "^1.0.0"
   },
diff --git a/src/async-components/views/dialogs/ExportE2eKeysDialog.js b/src/async-components/views/dialogs/ExportE2eKeysDialog.js
new file mode 100644
index 0000000000..284d299f4b
--- /dev/null
+++ b/src/async-components/views/dialogs/ExportE2eKeysDialog.js
@@ -0,0 +1,84 @@
+/*
+Copyright 2017 Vector Creations Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+
+import sdk from '../../../index';
+
+import * as MegolmExportEncryption from '../../../utils/MegolmExportEncryption';
+
+export default React.createClass({
+    displayName: 'ExportE2eKeysDialog',
+
+    getInitialState: function() {
+        return {
+            collectedPassword: false,
+        };
+    },
+
+    _onPassphraseFormSubmit: function(ev) {
+        ev.preventDefault();
+        console.log(this.refs.passphrase1.value);
+        return false;
+    },
+
+    render: function() {
+        let content;
+        if (!this.state.collectedPassword) {
+            content = (
+                <div className="mx_Dialog_content">
+                    <p>
+                        This process will allow you to export the keys for messages
+                        you have received in encrypted rooms to a local file. You
+                        will then be able to import the file into another Matrix
+                        client in the future, so that client will also be able to
+                        decrypt these messages.
+                    </p>
+                    <p>
+                        The exported file will allow anyone who can read it to decrypt
+                        any encrypted messages that you can see, so you should be
+                        careful to keep it secure. To help with this, you should enter
+                        a passphrase below, which will be used to encrypt the exported
+                        data. It will only be possible to import the data by using the
+                        same passphrase.
+                    </p>
+                    <form onSubmit={this._onPassphraseFormSubmit}>
+                        <div className="mx_TextInputDialog_label">
+                            <label htmlFor="passphrase1">Enter passphrase</label>
+                        </div>
+                        <div>
+                            <input ref="passphrase1" id="passphrase1"
+                                className="mx_TextInputDialog_input"
+                                autoFocus={true} size="64" type="password"/>
+                        </div>
+                        <div className="mx_Dialog_buttons">
+                            <input className="mx_Dialog_primary" type="submit" value="Export" />
+                        </div>
+                    </form>
+                </div>
+            );
+        }
+
+        return (
+            <div className="mx_exportE2eKeysDialog">
+                <div className="mx_Dialog_title">
+                    Export room keys
+                </div>
+                {content}
+            </div>
+        );
+    },
+});
diff --git a/src/utils/MegolmExportEncryption.js b/src/utils/MegolmExportEncryption.js
index 351f58aaa6..e3ca7e68f2 100644
--- a/src/utils/MegolmExportEncryption.js
+++ b/src/utils/MegolmExportEncryption.js
@@ -17,13 +17,14 @@ limitations under the License.
 "use strict";
 
 // polyfill textencoder if necessary
+import * as TextEncodingUtf8 from 'text-encoding-utf-8';
 let TextEncoder = window.TextEncoder;
 if (!TextEncoder) {
-    TextEncoder = require('./TextEncoderPolyfill');
+    TextEncoder = TextEncodingUtf8.TextEncoder;
 }
 let TextDecoder = window.TextDecoder;
-if (TextDecoder) {
-    TextDecoder = require('./TextDecoderPolyfill');
+if (!TextDecoder) {
+    TextDecoder = TextEncodingUtf8.TextDecoder;
 }
 
 const subtleCrypto = window.crypto.subtle || window.crypto.webkitSubtle;
diff --git a/src/utils/TextDecoderPolyfill.js b/src/utils/TextDecoderPolyfill.js
deleted file mode 100644
index e203676bb7..0000000000
--- a/src/utils/TextDecoderPolyfill.js
+++ /dev/null
@@ -1,131 +0,0 @@
-/*
-Copyright 2017 Vector Creations Ltd
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-"use strict";
-
-// Polyfill for TextDecoder.
-
-const REPLACEMENT_CHAR = '\uFFFD';
-
-export default class TextDecoder {
-    /**
-     * Decode a UTF-8 byte array as a javascript string
-     *
-     * @param {Uint8Array} u8Array UTF-8-encoded onput
-     * @return {str}
-     */
-    decode(u8Array) {
-        let u0, u1, u2, u3;
-
-        let str = '';
-        let idx = 0;
-        while (idx < u8Array.length) {
-            u0 = u8Array[idx++];
-            if (!(u0 & 0x80)) {
-                str += String.fromCharCode(u0);
-                continue;
-            }
-
-            if ((u0 & 0xC0) != 0xC0) {
-                // continuation byte where we expect a leading byte
-                str += REPLACEMENT_CHAR;
-                continue;
-            }
-
-            if (u0 > 0xF4) {
-                // this would imply a 5-byte or longer encoding, which is
-                // invalid and unsupported here.
-                str += REPLACEMENT_CHAR;
-                continue;
-            }
-
-            u1 = u8Array[idx++];
-            if (u1 === undefined) {
-                str += REPLACEMENT_CHAR;
-                continue;
-            }
-
-            if ((u1 & 0xC0) != 0x80) {
-                // leading byte where we expect a continuation byte
-                str += REPLACEMENT_CHAR.repeat(2);
-                continue;
-            }
-            u1 &= 0x3F;
-            if (!(u0 & 0x20)) {
-                const u = ((u0 & 0x1F) << 6) | u1;
-                if (u < 0x80) {
-                    // over-long
-                    str += REPLACEMENT_CHAR.repeat(2);
-                } else {
-                    str += String.fromCharCode(u);
-                }
-                continue;
-            }
-
-            u2 = u8Array[idx++];
-            if (u2 === undefined) {
-                str += REPLACEMENT_CHAR.repeat(2);
-                continue;
-            }
-            if ((u2 & 0xC0) != 0x80) {
-                // leading byte where we expect a continuation byte
-                str += REPLACEMENT_CHAR.repeat(3);
-                continue;
-            }
-            u2 &= 0x3F;
-            if (!(u0 & 0x10)) {
-                const u = ((u0 & 0x0F) << 12) | (u1 << 6) | u2;
-                if (u < 0x800) {
-                    // over-long
-                    str += REPLACEMENT_CHAR.repeat(3);
-                } else if (u == 0xFEFF && idx == 3) {
-                    // byte-order mark: do not add to output
-                } else {
-                    str += String.fromCharCode(u);
-                }
-                continue;
-            }
-
-            u3 = u8Array[idx++];
-            if (u3 === undefined) {
-                str += REPLACEMENT_CHAR.repeat(3);
-                continue;
-            }
-            if ((u3 & 0xC0) != 0x80) {
-                // leading byte where we expect a continuation byte
-                str += REPLACEMENT_CHAR.repeat(4);
-                continue;
-            }
-            u3 &= 0x3F;
-            const u = ((u0 & 7) << 18) | (u1 << 12) | (u2 << 6) | u3;
-            if (u < 0x10000) {
-                // over-long
-                str += REPLACEMENT_CHAR.repeat(4);
-                continue;
-            }
-            if (u > 0x1FFFF) {
-                // unicode stops here.
-                str += REPLACEMENT_CHAR.repeat(4);
-                continue;
-            }
-
-            // encode as utf-16
-            const v = u - 0x10000;
-            str += String.fromCharCode(0xD800 | (v >> 10), 0xDC00 | (v & 0x3FF));
-        }
-        return str;
-    }
-}
diff --git a/src/utils/TextEncoderPolyfill.js b/src/utils/TextEncoderPolyfill.js
deleted file mode 100644
index 41ee4782a9..0000000000
--- a/src/utils/TextEncoderPolyfill.js
+++ /dev/null
@@ -1,78 +0,0 @@
-/*
-Copyright 2017 Vector Creations Ltd
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-"use strict";
-
-// Polyfill for TextEncoder. Based on emscripten's stringToUTF8Array.
-
-function utf8len(str) {
-    var len = 0;
-    for (var i = 0; i < str.length; ++i) {
-        var u = str.charCodeAt(i);
-        if (u >= 0xD800 && u <= 0xDFFF && i < str.length-1) {
-            // lead surrogate - combine with next surrogate
-            u = 0x10000 + ((u & 0x3FF) << 10) | (str.charCodeAt(++i) & 0x3FF);
-        }
-
-        if (u <= 0x7F) {
-            ++len;
-        } else if (u <= 0x7FF) {
-            len += 2;
-        } else if (u <= 0xFFFF) {
-            len += 3;
-        } else {
-            len += 4;
-        }
-    }
-    return len;
-}
-
-export default class TextEncoder {
-    /**
-     * Encode a javascript string as utf-8
-     *
-     * @param {String} str String to encode
-     * @return {Uint8Array} UTF-8-encoded output
-     */
-    encode(str) {
-        const outU8Array = new Uint8Array(utf8len(str));
-        var outIdx = 0;
-        for (var i = 0; i < str.length; ++i) {
-            var u = str.charCodeAt(i);
-            if (u >= 0xD800 && u <= 0xDFFF && i < str.length-1) {
-                // lead surrogate - combine with next surrogate
-                u = 0x10000 + ((u & 0x3FF) << 10) | (str.charCodeAt(++i) & 0x3FF);
-            }
-
-            if (u <= 0x7F) {
-                outU8Array[outIdx++] = u;
-            } else if (u <= 0x7FF) {
-                outU8Array[outIdx++] = 0xC0 | (u >> 6);
-                outU8Array[outIdx++] = 0x80 | (u & 0x3F);
-            } else if (u <= 0xFFFF) {
-                outU8Array[outIdx++] = 0xE0 | (u >> 12);
-                outU8Array[outIdx++] = 0x80 | ((u >> 6) & 0x3F);
-                outU8Array[outIdx++] = 0x80 | (u & 0x3F);
-            } else {
-                outU8Array[outIdx++] = 0xF0 | (u >> 18);
-                outU8Array[outIdx++] = 0x80 | ((u >> 12) & 0x3F);
-                outU8Array[outIdx++] = 0x80 | ((u >> 6) & 0x3F);
-                outU8Array[outIdx++] = 0x80 | (u & 0x3F);
-            }
-        }
-        return outU8Array;
-    }
-}
diff --git a/test/utils/TextDecoderPolyfill-test.js b/test/utils/TextDecoderPolyfill-test.js
deleted file mode 100644
index 84f5edf187..0000000000
--- a/test/utils/TextDecoderPolyfill-test.js
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
-Copyright 2017 Vector Creations Ltd
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-"use strict";
-
-import TextDecoderPolyfill from 'utils/TextDecoderPolyfill';
-
-import * as testUtils from '../test-utils';
-import expect from 'expect';
-
-describe('textDecoderPolyfill', function() {
-    beforeEach(function() {
-        testUtils.beforeEach(this);
-    });
-
-    it('should correctly decode a range of strings', function() {
-        const decoder = new TextDecoderPolyfill();
-
-        expect(decoder.decode(Uint8Array.of(65, 66, 67))).toEqual('ABC');
-        expect(decoder.decode(Uint8Array.of(0xC3, 0xA6))).toEqual('æ');
-        expect(decoder.decode(Uint8Array.of(0xE2, 0x82, 0xAC))).toEqual('€');
-        expect(decoder.decode(Uint8Array.of(0xF0, 0x9F, 0x92, 0xA9))).toEqual('\uD83D\uDCA9');
-    });
-
-    it('should ignore byte-order marks', function() {
-        const decoder = new TextDecoderPolyfill();
-        expect(decoder.decode(Uint8Array.of(0xEF, 0xBB, 0xBF, 65)))
-            .toEqual('A');
-    });
-
-    it('should not ignore byte-order marks in the middle of the array', function() {
-        const decoder = new TextDecoderPolyfill();
-        expect(decoder.decode(Uint8Array.of(65, 0xEF, 0xBB, 0xBF, 66)))
-            .toEqual('A\uFEFFB');
-    });
-
-    it('should reject overlong encodings', function() {
-        const decoder = new TextDecoderPolyfill();
-
-        // euro, as 4 bytes
-        expect(decoder.decode(Uint8Array.of(65, 0xF0, 0x82, 0x82, 0xAC, 67)))
-            .toEqual('A\uFFFD\uFFFD\uFFFD\uFFFDC');
-    });
-
-    it('should reject 5 and 6-byte encodings', function() {
-        const decoder = new TextDecoderPolyfill();
-
-        expect(decoder.decode(Uint8Array.of(65, 0xF8, 0x82, 0x82, 0x82, 0x82, 67)))
-            .toEqual('A\uFFFD\uFFFD\uFFFD\uFFFD\uFFFDC');
-    });
-
-    it('should reject code points beyond 0x10000', function() {
-        const decoder = new TextDecoderPolyfill();
-
-        expect(decoder.decode(Uint8Array.of(0xF4, 0xA0, 0x80, 0x80)))
-            .toEqual('\uFFFD\uFFFD\uFFFD\uFFFD');
-    });
-
-    it('should cope with end-of-string', function() {
-        const decoder = new TextDecoderPolyfill();
-
-        expect(decoder.decode(Uint8Array.of(65, 0xC3)))
-            .toEqual('A\uFFFD');
-
-        expect(decoder.decode(Uint8Array.of(65, 0xE2, 0x82)))
-            .toEqual('A\uFFFD\uFFFD');
-
-        expect(decoder.decode(Uint8Array.of(65, 0xF0, 0x9F, 0x92)))
-            .toEqual('A\uFFFD\uFFFD\uFFFD');
-    });
-
-});
diff --git a/test/utils/TextEncoderPolyfill-test.js b/test/utils/TextEncoderPolyfill-test.js
deleted file mode 100644
index 4f422ec375..0000000000
--- a/test/utils/TextEncoderPolyfill-test.js
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
-Copyright 2017 Vector Creations Ltd
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-"use strict";
-
-import TextEncoderPolyfill from 'utils/TextEncoderPolyfill';
-
-import * as testUtils from '../test-utils';
-import expect from 'expect';
-
-describe('textEncoderPolyfill', function() {
-    beforeEach(function() {
-        testUtils.beforeEach(this);
-    });
-
-    it('should correctly encode a range of strings', function() {
-        const encoder = new TextEncoderPolyfill();
-
-        expect(encoder.encode('ABC')).toEqual(Uint8Array.of(65, 66, 67));
-        expect(encoder.encode('æ')).toEqual(Uint8Array.of(0xC3, 0xA6));
-        expect(encoder.encode('€')).toEqual(Uint8Array.of(0xE2, 0x82, 0xAC));
-
-        // PILE OF POO (💩)
-        expect(encoder.encode('\uD83D\uDCA9')).toEqual(Uint8Array.of(0xF0, 0x9F, 0x92, 0xA9));
-    });
-});