shorten introduction

inbox/automatic-trust-transfer.xml

@@ -44,14 +44,14 @@
 		ATT is used for automatically establishing secure channels protected against active attacks between a new device and existing ones after a single mutual manual authentication between the new device and one of the existing ones.
 		It preserves the security level as if all devices had authenticated their keys manually.
 		A trusted third party is not required since a usual OMEMO message is used for transferring the information needed to authenticate a key or revoke the trust in that key.
-		Additionally, it will preserve the anonymity of the authentication and revocation since those messages are only sent to devices with authenticated keys.
-		That means that an attacker cannot detect whether an authentication or revocation took place.
+		Additionally, it preserves the anonymity of the authentication and revocation since those messages are only sent to devices with authenticated keys.
+		That means an attacker cannot detect whether an authentication or revocation took place.
 	</p>
 	<p>
-		End-to-end encryption without verifying the authenticity of the public keys enables users to protect their communication against passive attacks.
-		That means an attacker cannot read the transferred messages without manipulating the exchanged messages or key material.
+		End-to-end encryption without verifying the authenticity of the keys enables users to protect their communication against passive attacks.
+		This means an attacker cannot read the transferred messages without manipulating the exchanged keys.
 		But without any other precautions active attacks are still possible.
-		If the exchanged keys are replaced with the key of an attacker, the end-to-end encrypted messages can be read by the attacker.
+		If an attacker replaces the exchanged keys with a malicious key, the end-to-end encrypted messages can be read and manipulated by the attacker.
 	</p>
 	<p>
 		When using &xep0384;, a public identity key is transmitted over a channel which is not protected against active attacks.
@@ -61,34 +61,8 @@
 		When using OMEMO, each device has a different identity key.
 		That makes it possible for new devices to use end-to-end encryption protecting against passive attacks without transmitting the private key over a secure channel from an existing device to the new one.
 		However, the downside of this approach is that it increases the number of authentications.
-	</p>
-	<p>
-		The goal of key authentication is to build up an end-to-end encrypted communication network exclusively between devices with authenticated keys.
-		That network of devices trusting each other's keys can be seen as a complete graph with each device as a node and each authentication as an edge.
-		The number of edges grows for each new device by the number of existing nodes.
-		Without ATT all of those authentications have to be done manually.
-		With ATT though, only one mutal manual authentication is required.
-	</p>
-	<p>
-		This means that each communication channel between the devices is resistant against active attacks.
-		To sustain such a secure communication across all devices, the new key of an own device has to be authenticated by all n own devices and all m devices of a contact.
-		This leads to a total of n * m authentications.
-		Two of them require user interaction like scanning each other's QR codes or comparing the key identifiers by hand.
-		The remaining authentications can be automated relying on the secure channel established by the two inital authentications and the secure channels created by that procedure.
-		Thus, less user interaction is needed for authenticating all keys involved in the secure communication while preserving the same security level.
-	</p>
-	<p>
-		On the one hand, each new key has to be authenticated by a device that already belongs to the devices communicating with authenticated keys.
-		On the other hand, the device that introduces the new key has to authenticate the key of the device that already belongs to the devices communicating with authenticated keys.
-	</p>
-	<p>
-		More precisely, that means the following:
-		After device 1 manually authenticated the key of device 2, a message called authentication message for the key of device 2 is sent automatically from device 1 to devices with already authenticated keys.
-		They can use the authentication message for an automatic authentication of the key of device 2 after they authenticated the key of device 1.
-	</p>
-	<p>
-		When a key of an own device should not be trusted anymore by other own devices and devices of a contact, an appropriate message can be sent to those devices.
-		They can then revoke the trust in that key if the key of the sending device is already authenticated.
+		Without ATT all authentications have to be done manually.
+		With ATT though, only one mutal manual authentication per new key is required.
 	</p>
 </section1>
 <section1 topic='Glossary' anchor='glossary'>