diff --git a/matrix_sdk_crypto/src/verification/sas.rs b/matrix_sdk_crypto/src/verification/sas.rs
index 475e3e63..134ab1bc 100644
--- a/matrix_sdk_crypto/src/verification/sas.rs
+++ b/matrix_sdk_crypto/src/verification/sas.rs
@@ -1,10 +1,17 @@
 use crate::Device;
 
-use matrix_sdk_common::events::key::verification::{
-    accept::AcceptEvent,
-    start::{StartEvent, StartEventContent},
-    HashAlgorithm, KeyAgreementProtocol, MessageAuthenticationCode, ShortAuthenticationString,
-    VerificationMethod,
+use olm_rs::sas::OlmSas;
+
+use matrix_sdk_common::events::{
+    key::verification::{
+        accept::AcceptEvent,
+        key::KeyEvent,
+        mac::MacEvent,
+        start::{MSasV1Content, MSasV1ContentOptions, StartEvent, StartEventContent},
+        HashAlgorithm, KeyAgreementProtocol, MessageAuthenticationCode, ShortAuthenticationString,
+        VerificationMethod,
+    },
+    ToDeviceEvent,
 };
 use matrix_sdk_common::identifiers::{DeviceId, UserId};
 use matrix_sdk_common::uuid::Uuid;
@@ -15,13 +22,6 @@ struct SasIds {
     other_device: Device,
 }
 
-struct ProtocolDefinitions {
-    key_agreement_protocols: Vec<KeyAgreementProtocol>,
-    hashes: Vec<HashAlgorithm>,
-    message_auth_codes: Vec<MessageAuthenticationCode>,
-    short_auth_string: Vec<ShortAuthenticationString>,
-}
-
 struct AcceptedProtocols {
     method: VerificationMethod,
     key_agreement_protocol: KeyAgreementProtocol,
@@ -31,43 +31,61 @@ struct AcceptedProtocols {
 }
 
 struct Sas<S> {
+    inner: OlmSas,
     ids: SasIds,
     verification_flow_id: Uuid,
-    protocol_definitions: ProtocolDefinitions,
     state: S,
 }
 
+impl<S> Sas<S> {
+    pub fn user_id(&self) -> &UserId {
+        &self.ids.own_user_id
+    }
+}
+
 impl Sas<Created> {
     fn new(own_user_id: UserId, own_device_id: &DeviceId, other_device: Device) -> Sas<Created> {
+        let verification_flow_id = Uuid::new_v4();
+
         Sas {
+            inner: OlmSas::new(),
             ids: SasIds {
                 own_user_id,
                 own_device_id: own_device_id.into(),
                 other_device,
             },
-            verification_flow_id: Uuid::new_v4(),
+            verification_flow_id,
 
-            protocol_definitions: ProtocolDefinitions {
-                short_auth_string: vec![
-                    ShortAuthenticationString::Decimal,
-                    ShortAuthenticationString::Emoji,
-                ],
-                key_agreement_protocols: vec![KeyAgreementProtocol::Curve25519],
-                message_auth_codes: vec![MessageAuthenticationCode::HkdfHmacSha256],
-                hashes: vec![HashAlgorithm::Sha256],
+            state: Created {
+                protocol_definitions: MSasV1ContentOptions {
+                    transaction_id: verification_flow_id.to_string(),
+                    from_device: own_device_id.into(),
+                    short_authentication_string: vec![
+                        ShortAuthenticationString::Decimal,
+                        ShortAuthenticationString::Emoji,
+                    ],
+                    key_agreement_protocols: vec![KeyAgreementProtocol::Curve25519HkdfSha256],
+                    message_authentication_codes: vec![MessageAuthenticationCode::HkdfHmacSha256],
+                    hashes: vec![HashAlgorithm::Sha256],
+                },
             },
-
-            state: Created {},
         }
     }
 
+    fn get_start_event(&self) -> StartEventContent {
+        StartEventContent::MSasV1(
+            MSasV1Content::new(self.state.protocol_definitions.clone())
+                .expect("Invalid initial protocol definitions."),
+        )
+    }
+
     fn into_accepted(self, event: &AcceptEvent) -> Sas<Accepted> {
         let content = &event.content;
 
         Sas {
+            inner: self.inner,
             ids: self.ids,
             verification_flow_id: self.verification_flow_id,
-            protocol_definitions: self.protocol_definitions,
             state: Accepted {
                 commitment: content.commitment.clone(),
                 accepted_protocols: AcceptedProtocols {
@@ -82,16 +100,20 @@ impl Sas<Created> {
     }
 }
 
-struct Created {}
+struct Created {
+    protocol_definitions: MSasV1ContentOptions,
+}
 
-struct Started {}
+struct Started {
+    protocol_definitions: MSasV1Content,
+}
 
 impl Sas<Started> {
     fn from_start_event(
-        own_user_id: UserId,
+        own_user_id: &UserId,
         own_device_id: &DeviceId,
         other_device: Device,
-        event: &StartEvent,
+        event: &ToDeviceEvent<StartEventContent>,
     ) -> Sas<Started> {
         let content = if let StartEventContent::MSasV1(content) = &event.content {
             content
@@ -100,26 +122,134 @@ impl Sas<Started> {
         };
 
         Sas {
+            inner: OlmSas::new(),
+
             ids: SasIds {
-                own_user_id,
+                own_user_id: own_user_id.clone(),
                 own_device_id: own_device_id.into(),
                 other_device,
             },
+
             verification_flow_id: Uuid::new_v4(),
 
-            protocol_definitions: ProtocolDefinitions {
-                short_auth_string: content.short_authentication_string.clone(),
-                key_agreement_protocols: content.key_agreement_protocols.clone(),
-                message_auth_codes: content.message_authentication_codes.clone(),
-                hashes: content.hashes.clone(),
+            state: Started {
+                protocol_definitions: content.clone(),
             },
-
-            state: Started {},
         }
     }
+
+    fn into_key_received(self, event: &KeyEvent) -> Sas<KeyReceived> {
+        todo!()
+    }
 }
 
 struct Accepted {
     accepted_protocols: AcceptedProtocols,
     commitment: String,
 }
+
+impl Sas<Accepted> {
+    fn into_key_received(self, event: &KeyEvent) -> Sas<KeyReceived> {
+        todo!()
+    }
+}
+
+struct KeyReceived {
+    accepted_protocols: AcceptedProtocols,
+}
+
+impl Sas<KeyReceived> {
+    fn into_mac_received(self, event: &MacEvent) -> Sas<MacReceived> {
+        todo!()
+    }
+
+    fn confirm(self) -> Sas<Confirmed> {
+        todo!()
+    }
+}
+
+struct Confirmed {
+    accepted_protocols: AcceptedProtocols,
+}
+
+impl Sas<Confirmed> {
+    fn confirm(self) -> Sas<Done> {
+        todo!()
+    }
+}
+
+struct MacReceived {
+    verified_devices: Vec<String>,
+    verified_master_keys: Vec<String>,
+}
+
+impl Sas<MacReceived> {
+    fn into_done(self, event: &MacEvent) -> Sas<Done> {
+        todo!()
+    }
+}
+
+struct Done {
+    verified_devices: Vec<String>,
+    verified_master_keys: Vec<String>,
+}
+
+#[cfg(test)]
+mod test {
+    use std::convert::TryFrom;
+
+    use crate::{Account, Device};
+    use matrix_sdk_common::events::key::verification::{
+        accept::AcceptEvent,
+        key::KeyEvent,
+        mac::MacEvent,
+        start::{MSasV1Content, MSasV1ContentOptions, StartEvent, StartEventContent},
+    };
+    use matrix_sdk_common::events::{AnyToDeviceEvent, ToDeviceEvent};
+    use matrix_sdk_common::identifiers::{DeviceId, UserId};
+
+    use super::{Created, Sas, Started};
+
+    fn alice_id() -> UserId {
+        UserId::try_from("@alice:example.org").unwrap()
+    }
+
+    fn alice_device_id() -> Box<DeviceId> {
+        "JLAFKJWSCS".into()
+    }
+
+    fn bob_id() -> UserId {
+        UserId::try_from("@bob:example.org").unwrap()
+    }
+
+    fn bob_device_id() -> Box<DeviceId> {
+        "BOBDEVCIE".into()
+    }
+
+    fn wrap_start_event(
+        sender: &UserId,
+        content: StartEventContent,
+    ) -> ToDeviceEvent<StartEventContent> {
+        ToDeviceEvent {
+            sender: sender.clone(),
+            content,
+        }
+    }
+
+    #[tokio::test]
+    async fn create_sas() {
+        let alice = Account::new(&alice_id(), &alice_device_id());
+        let alice_device = Device::from_account(&alice).await;
+
+        let bob = Account::new(&bob_id(), &bob_device_id());
+        let bob_device = Device::from_account(&bob).await;
+
+        let alice_sas = Sas::<Created>::new(alice_id(), &alice_device_id(), bob_device);
+
+        let start_content = alice_sas.get_start_event();
+        let event = wrap_start_event(alice_sas.user_id(), start_content);
+
+        let bob_sas =
+            Sas::<Started>::from_start_event(bob.user_id(), bob.device_id(), alice_device, &event);
+    }
+}