diff --git a/res/css/_components.scss b/res/css/_components.scss
index 1e2d7ae156..70c2f17e9a 100644
--- a/res/css/_components.scss
+++ b/res/css/_components.scss
@@ -60,6 +60,7 @@
 @import "./views/elements/_DirectorySearchBox.scss";
 @import "./views/elements/_Dropdown.scss";
 @import "./views/elements/_EditableItemList.scss";
+@import "./views/elements/_HexVerify.scss";
 @import "./views/elements/_ImageView.scss";
 @import "./views/elements/_InlineSpinner.scss";
 @import "./views/elements/_MemberEventListSummary.scss";
diff --git a/res/css/views/elements/_HexVerify.scss b/res/css/views/elements/_HexVerify.scss
new file mode 100644
index 0000000000..3f3ee4b7ea
--- /dev/null
+++ b/res/css/views/elements/_HexVerify.scss
@@ -0,0 +1,34 @@
+/*
+Copyright 2019 New Vector 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.
+*/
+
+.mx_HexVerify {
+    text-align: center;
+}
+
+.mx_HexVerify_pair {
+    display: inline-block;
+    font-weight: bold;
+    padding-left: 3px;
+    padding-right: 3px;
+}
+
+.mx_HexVerify_pair_verified {
+    color: $accent-color;
+}
+
+.mx_HexVerify_pair:hover{
+    color: $accent-color;
+}
diff --git a/src/components/views/dialogs/DeviceVerifyDialog.js b/src/components/views/dialogs/DeviceVerifyDialog.js
index 169dc26c52..eabae56e25 100644
--- a/src/components/views/dialogs/DeviceVerifyDialog.js
+++ b/src/components/views/dialogs/DeviceVerifyDialog.js
@@ -50,6 +50,7 @@ export default class DeviceVerifyDialog extends React.Component {
         this.state = {
             phase: PHASE_START,
             mode: SettingsStore.isFeatureEnabled("feature_sas") ? MODE_SAS : MODE_LEGACY,
+            sasVerified: false,
         };
     }
 
@@ -102,6 +103,10 @@ export default class DeviceVerifyDialog extends React.Component {
         });
     }
 
+    _onVerifyStateChanged = (newVal) => {
+        this.setState({sasVerified: newVal});
+    }
+
     _onSasMatchesClick = () => {
         this._showSasEvent.confirm();
         this.setState({
@@ -127,7 +132,6 @@ export default class DeviceVerifyDialog extends React.Component {
                 body = this._renderSasVerificationPhaseStart();
                 break;
             case PHASE_WAIT_FOR_PARTNER_TO_ACCEPT:
-                //body = this._renderSasVerificationPhaseWaitForPartnerToAccept();
                 body = renderSasWaitAccept(this.props.userId);
                 break;
             case PHASE_SHOW_SAS:
@@ -180,6 +184,7 @@ export default class DeviceVerifyDialog extends React.Component {
 
     _renderSasVerificationPhaseShowSas() {
         const DialogButtons = sdk.getComponent('views.elements.DialogButtons');
+        const HexVerify = sdk.getComponent('views.elements.HexVerify');
         return <div>
             <p>{_t(
                 "Verify this user by confirming the following number appears on their screen"
@@ -188,9 +193,15 @@ export default class DeviceVerifyDialog extends React.Component {
                 "For maximum security, we reccommend you do this in person or use another " +
                 "trusted means of communication"
             )}</p>
-            <pre>{this._showSasEvent.sas}</pre>
+            <HexVerify text={this._showSasEvent.sas}
+                onVerifiedStateChange={this._onVerifyStateChanged}
+            />
+            <p>{_t(
+                "To continue, click on each pair to confirm it's correct.",
+            )}</p>
             <DialogButtons onPrimaryButtonClick={this._onSasMatchesClick}
-                primaryButton={_t("This Matches")}
+                primaryButton={_t("Continue")}
+                primaryDisabled={!this.state.sasVerified}
                 hasCancel={true}
                 onCancel={this._onCancelClick}
             />
diff --git a/src/components/views/dialogs/IncomingSasDialog.js b/src/components/views/dialogs/IncomingSasDialog.js
index 732ce2a461..947c757f80 100644
--- a/src/components/views/dialogs/IncomingSasDialog.js
+++ b/src/components/views/dialogs/IncomingSasDialog.js
@@ -38,6 +38,7 @@ export default class IncomingSasDialog extends React.Component {
         this._showSasEvent = null;
         this.state = {
             phase: PHASE_START,
+            sasVerified: false,
         };
         this.props.verifier.on('show_sas', this._onVerifierShowSas);
         this.props.verifier.on('cancel', this._onVerifierCancel);
@@ -81,6 +82,10 @@ export default class IncomingSasDialog extends React.Component {
         });
     }
 
+    _onVerifiedStateChange = (newVal) => {
+        this.setState({sasVerified: newVal});
+    }
+
     _onSasMatchesClick = () => {
         this._showSasEvent.confirm();
         this.setState({
@@ -121,6 +126,7 @@ export default class IncomingSasDialog extends React.Component {
 
     _renderPhaseShowSas() {
         const DialogButtons = sdk.getComponent('views.elements.DialogButtons');
+        const HexVerify = sdk.getComponent('views.elements.HexVerify');
         return <div>
             <p>{_t(
                 "Verify this user by confirming the following number appears on their screen"
@@ -129,9 +135,15 @@ export default class IncomingSasDialog extends React.Component {
                 "For maximum security, we reccommend you do this in person or use another " +
                 "trusted means of communication"
             )}</p>
-            <pre>{this._showSasEvent.sas}</pre>
+            <HexVerify text={this._showSasEvent.sas}
+                onVerifiedStateChange={this._onVerifiedStateChange}
+            />
+            <p>{_t(
+                "To continue, click on each pair to confirm it's correct.",
+            )}</p>
             <DialogButtons onPrimaryButtonClick={this._onSasMatchesClick}
-                primaryButton={_t("This Matches")}
+                primaryButton={_t("Continue")}
+                primaryDisabled={!this.state.sasVerified}
                 hasCancel={true}
                 onCancel={this._onCancelClick}
             />
@@ -184,7 +196,6 @@ export default class IncomingSasDialog extends React.Component {
     }
 
     render() {
-        console.log("rendering pahse "+this.state.phase);
         let body;
         switch (this.state.phase) {
             case PHASE_START:
diff --git a/src/components/views/elements/HexVerify.js b/src/components/views/elements/HexVerify.js
new file mode 100644
index 0000000000..667857a792
--- /dev/null
+++ b/src/components/views/elements/HexVerify.js
@@ -0,0 +1,104 @@
+/*
+Copyright 2019 New Vector 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 PropTypes from "prop-types";
+import { _t } from '../../../languageHandler';
+import classnames from 'classnames';
+
+import sdk from '../../../index';
+
+class HexVerifyPair extends React.Component {
+    static propTypes = {
+        text: PropTypes.string.isRequired,
+        index: PropTypes.number,
+        verified: PropTypes.bool,
+        onChange: PropTypes.func.isRequired,
+    }
+
+    _onClick = () => {
+        this.setState({verified: !this.props.verified});
+        this.props.onChange(this.props.index, !this.props.verified);
+    }
+
+    render() {
+        const classNames = {
+            mx_HexVerify_pair: true,
+            mx_HexVerify_pair_verified: this.props.verified,
+        };
+        const AccessibleButton = sdk.getComponent('views.elements.AccessibleButton');
+        return <AccessibleButton className={classnames(classNames)} 
+            onClick={this._onClick}
+        >
+            {this.props.text}
+        </AccessibleButton>
+    }
+}
+
+/**
+ * Helps a user verify a hexadecimal code matches one displayed
+ * elsewhere (eg. on a different device)
+ */
+export default class HexVerify extends React.Component {
+    static propTypes = {
+        text: PropTypes.string.isRequired,
+        onVerifiedStateChange: PropTypes.func,
+    }
+
+    static defaultProps = {
+        onVerifiedStateChange: function() {},
+    }
+
+    constructor(props) {
+        super(props);
+        this.state = {
+            pairsVerified: [],
+        };
+        for (let i = 0; i < props.text.length; i += 2) {
+            this.state.pairsVerified.push(false);
+        }
+    }
+
+    _onPairChange = (index, newVal) => {
+        const oldVerified = this.state.pairsVerified.reduce((acc, val) => {
+            return acc && val;
+        }, true);
+        const newPairsVerified = this.state.pairsVerified.slice(0);
+        newPairsVerified[index] = newVal;
+        const newVerified = newPairsVerified.reduce((acc, val) => {
+            return acc && val;
+        }, true);
+        this.setState({pairsVerified: newPairsVerified});
+        if (oldVerified !== newVerified) {
+            this.props.onVerifiedStateChange(newVerified);
+        }
+    }
+
+    render() {
+        const pairs = [];
+
+        for (let i = 0; i < this.props.text.length / 2; ++i) {
+            pairs.push(<HexVerifyPair key={i} index={i}
+                text={this.props.text.substr(i * 2, 2)}
+                verified={this.state.pairsVerified[i]}
+                onChange={this._onPairChange}
+            />);
+        }
+        return <div className="mx_HexVerify">
+            {pairs}
+        </div>;
+    }
+}
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index c26330dda4..7f61a13a21 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -947,7 +947,7 @@
     "Send Verification Request": "Send Verification Request",
     "Verify this user by confirming the following number appears on their screen": "Verify this user by confirming the following number appears on their screen",
     "For maximum security, we reccommend you do this in person or use another trusted means of communication": "For maximum security, we reccommend you do this in person or use another trusted means of communication",
-    "This Matches": "This Matches",
+    "To continue, click on each pair to confirm it's correct.": "To continue, click on each pair to confirm it's correct.",
     "Verification complete!": "Verification complete!",
     "Done": "Done",
     "%(userId)s cancelled the verification.": "%(userId)s cancelled the verification.",