diff --git a/src/dummy.rs b/src/dummy.rs
new file mode 100644
index 00000000..8c82d160
--- /dev/null
+++ b/src/dummy.rs
@@ -0,0 +1,24 @@
+//! Types for the *m.dummy* event.
+
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+
+event! {
+    /// This event type is used to indicate new Olm sessions for end-to-end encryption.
+    ///
+    /// Typically it is encrypted as an *m.room.encrypted* event, then sent as a to-device event.
+    ///
+    /// The event does not have any content associated with it. The sending client is expected to
+    /// send a key share request shortly after this message, causing the receiving client to process
+    /// this *m.dummy* event as the most recent event and using the keyshare request to set up the
+    /// session. The keyshare request and *m.dummy* combination should result in the original
+    /// sending client receiving keys over the newly established session.
+    pub struct DummyEvent(DummyEventContent) {}
+}
+
+/// The payload of an *m.dummy* event.
+///
+/// The values in the hash map are not meaningful. They are used to generate an empty JSON
+/// object to support the structure used by the Matrix specification.
+pub type DummyEventContent = HashMap<(), ()>;
diff --git a/src/forwarded_room_key.rs b/src/forwarded_room_key.rs
new file mode 100644
index 00000000..ad0416c2
--- /dev/null
+++ b/src/forwarded_room_key.rs
@@ -0,0 +1,47 @@
+//! Types for the *m.forwarded_room_key* event.
+
+use ruma_identifiers::RoomId;
+use serde::{Deserialize, Serialize};
+
+use super::Algorithm;
+
+event! {
+    /// This event type is used to forward keys for end-to-end encryption.
+    ///
+    /// Typically it is encrypted as an *m.room.encrypted* event, then sent as a to-device event.
+    pub struct ForwardedRoomKeyEvent(ForwardedRoomKeyEventContent) {}
+}
+
+/// The payload of an *m.forwarded_room_key* event.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct ForwardedRoomKeyEventContent {
+    /// The encryption algorithm the key in this event is to be used with.
+    pub algorithm: Algorithm,
+
+    /// The room where the key is used.
+    pub room_id: RoomId,
+
+    /// The Curve25519 key of the device which initiated the session originally.
+    pub sender_key: String,
+
+    /// The ID of the session that the key is for.
+    pub session_id: String,
+
+    /// The key to be exchanged.
+    pub session_key: String,
+
+    /// The Ed25519 key of the device which initiated the session originally.
+    ///
+    /// It is "claimed" because the receiving device has no way to tell that the original room_key
+    /// actually came from a device which owns the private part of this key unless they have done
+    /// device verification.
+    pub sender_claimed_ed25519_key: String,
+
+    /// Chain of Curve25519 keys.
+    ///
+    /// It starts out empty, but each time the key is forwarded to another device, the previous
+    /// sender in the chain is added to the end of the list. For example, if the key is forwarded
+    /// from A to B to C, this field is empty between A and B, and contains A's Curve25519 key
+    /// between B and C.
+    pub forwarding_curve25519_key_chain: Vec<String>,
+}
diff --git a/src/key.rs b/src/key.rs
new file mode 100644
index 00000000..ccc5d32e
--- /dev/null
+++ b/src/key.rs
@@ -0,0 +1,3 @@
+//! Modules for events in the *m.key* namespace.
+
+pub mod verification;
diff --git a/src/key/verification.rs b/src/key/verification.rs
new file mode 100644
index 00000000..1ce06164
--- /dev/null
+++ b/src/key/verification.rs
@@ -0,0 +1,117 @@
+//! Modules for events in the *m.key.verification* namespace.
+//!
+//! This module also contains types shared by events in its child namespaces.
+
+use serde::{Deserialize, Serialize};
+
+pub mod accept;
+pub mod cancel;
+pub mod key;
+pub mod mac;
+pub mod request;
+pub mod start;
+
+/// A hash algorithm.
+#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+pub enum HashAlgorithm {
+    /// The SHA256 hash algorithm.
+    #[serde(rename = "sha256")]
+    Sha256,
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    #[serde(skip)]
+    __Nonexhaustive,
+}
+
+impl_enum! {
+    HashAlgorithm {
+        Sha256 => "sha256",
+    }
+}
+
+/// A key agreement protocol.
+#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+pub enum KeyAgreementProtocol {
+    /// The [Curve25519](https://cr.yp.to/ecdh.html) key agreement protocol.
+    #[serde(rename = "curve25519")]
+    Curve25519,
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    #[serde(skip)]
+    __Nonexhaustive,
+}
+
+impl_enum! {
+    KeyAgreementProtocol {
+        Curve25519 => "curve25519",
+    }
+}
+
+/// A message authentication code algorithm.
+#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+pub enum MessageAuthenticationCode {
+    /// The HKDF-HMAC-SHA256 MAC.
+    #[serde(rename = "hkdf-hmac-sha256")]
+    HkdfHmacSha256,
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    #[serde(skip)]
+    __Nonexhaustive,
+}
+
+impl_enum! {
+    MessageAuthenticationCode {
+        HkdfHmacSha256 => "hkdf-hmac-sha256",
+    }
+}
+
+/// A Short Authentication String method.
+#[derive(Clone, Copy, Debug, Serialize, PartialEq, Deserialize)]
+pub enum ShortAuthenticationString {
+    /// The decimal method.
+    #[serde(rename = "decimal")]
+    Decimal,
+
+    /// The emoji method.
+    #[serde(rename = "emoji")]
+    Emoji,
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    #[serde(skip)]
+    __Nonexhaustive,
+}
+
+impl_enum! {
+    ShortAuthenticationString {
+        Decimal => "decimal",
+        Emoji => "emoji",
+    }
+}
+
+/// A Short Authentication String (SAS) verification method.
+#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
+pub enum VerificationMethod {
+    /// The *m.sas.v1* verification method.
+    #[serde(rename = "m.sas.v1")]
+    MSasV1,
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    #[serde(skip)]
+    __Nonexhaustive,
+}
+
+impl_enum! {
+    VerificationMethod {
+        MSasV1 => "m.sas.v1",
+    }
+}
diff --git a/src/key/verification/accept.rs b/src/key/verification/accept.rs
new file mode 100644
index 00000000..74fdd662
--- /dev/null
+++ b/src/key/verification/accept.rs
@@ -0,0 +1,51 @@
+//! Types for the *m.key.verification.accept* event.
+
+use serde::{Deserialize, Serialize};
+
+use super::{
+    HashAlgorithm, KeyAgreementProtocol, MessageAuthenticationCode, ShortAuthenticationString,
+    VerificationMethod,
+};
+
+event! {
+    /// Accepts a previously sent *m.key.verification.start* messge.
+    ///
+    /// Typically sent as a to-device event.
+    pub struct AcceptEvent(AcceptEventContent) {}
+}
+
+/// The payload of an *m.key.verification.accept* event.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct AcceptEventContent {
+    /// An opaque identifier for the verification process.
+    ///
+    /// Must be the same as the one used for the *m.key.verification.start* message.
+    pub transaction_id: String,
+
+    /// The verification method to use.
+    ///
+    /// Must be `m.sas.v1`.
+    pub method: VerificationMethod,
+
+    /// The key agreement protocol the device is choosing to use, out of the options in the
+    /// *m.key.verification.start* message.
+    pub key_agreement_protocol: KeyAgreementProtocol,
+
+    /// The hash method the device is choosing to use, out of the options in the
+    /// *m.key.verification.start* message.
+    pub hash: HashAlgorithm,
+
+    /// The message authentication code the device is choosing to use, out of the options in the
+    /// *m.key.verification.start* message.
+    pub message_authentication_code: MessageAuthenticationCode,
+
+    /// The SAS methods both devices involved in the verification process understand.
+    ///
+    /// Must be a subset of the options in the *m.key.verification.start* message.
+    pub short_authentication_string: Vec<ShortAuthenticationString>,
+
+    /// The hash (encoded as unpadded base64) of the concatenation of the device's ephemeral public
+    /// key (encoded as unpadded base64) and the canonical JSON representation of the
+    /// *m.key.verification.start* message.
+    pub commitment: String,
+}
diff --git a/src/key/verification/cancel.rs b/src/key/verification/cancel.rs
new file mode 100644
index 00000000..8f5265b6
--- /dev/null
+++ b/src/key/verification/cancel.rs
@@ -0,0 +1,189 @@
+//! Types for the *m.key.verification.cancel* event.
+
+use std::fmt::{Display, Formatter, Result as FmtResult};
+
+use serde::{
+    de::{Error as SerdeError, Visitor},
+    Deserialize, Deserializer, Serialize, Serializer,
+};
+
+event! {
+    /// Cancels a key verification process/request.
+    ///
+    /// Typically sent as a to-device event.
+    pub struct CancelEvent(CancelEventContent) {}
+}
+
+/// The payload of an *m.key.verification.cancel* event.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct CancelEventContent {
+    /// The opaque identifier for the verification process/request.
+    pub transaction_id: String,
+
+    /// A human readable description of the `code`.
+    ///
+    /// The client should only rely on this string if it does not understand the `code`.
+    pub reason: String,
+
+    /// The error code for why the process/request was cancelled by the user.
+    pub code: CancelCode,
+}
+
+/// An error code for why the process/request was cancelled by the user.
+///
+/// Custom error codes should use the Java package naming convention.
+#[derive(Clone, Debug, PartialEq)]
+pub enum CancelCode {
+    /// The user cancelled the verification.
+    User,
+
+    /// The verification process timed out. Verification processes can define their own timeout
+    /// parameters.
+    Timeout,
+
+    /// The device does not know about the given transaction ID.
+    UnknownTransaction,
+
+    /// The device does not know how to handle the requested method.
+    ///
+    /// This should be sent for *m.key.verification.start* messages and messages defined by
+    /// individual verification processes.
+    UnknownMethod,
+
+    /// The device received an unexpected message.
+    ///
+    /// Typically raised when one of the parties is handling the verification out of order.
+    UnexpectedMessage,
+
+    /// The key was not verified.
+    KeyMismatch,
+
+    /// The expected user did not match the user verified.
+    UserMismatch,
+
+    /// The message received was invalid.
+    InvalidMessage,
+
+    /// An *m.key.verification.request* was accepted by a different device.
+    ///
+    /// The device receiving this error can ignore the verification request.
+    Accepted,
+
+    /// Any code that is not part of the specification.
+    Custom(String),
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Display for CancelCode {
+    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        let cancel_code_str = match *self {
+            CancelCode::User => "m.user",
+            CancelCode::Timeout => "m.timeout",
+            CancelCode::UnknownTransaction => "m.unknown_transaction",
+            CancelCode::UnknownMethod => "m.unknown_method",
+            CancelCode::UnexpectedMessage => "m.unexpected_message",
+            CancelCode::KeyMismatch => "m.key_mismatch",
+            CancelCode::UserMismatch => "m.user_mismatch",
+            CancelCode::InvalidMessage => "m.invalid_message",
+            CancelCode::Accepted => "m.accepted",
+            CancelCode::Custom(ref cancel_code) => cancel_code,
+            CancelCode::__Nonexhaustive => {
+                panic!("__Nonexhaustive enum variant is not intended for use.")
+            }
+        };
+
+        write!(f, "{}", cancel_code_str)
+    }
+}
+
+impl<'a> From<&'a str> for CancelCode {
+    fn from(s: &'a str) -> CancelCode {
+        match s {
+            "m.user" => CancelCode::User,
+            "m.timeout" => CancelCode::Timeout,
+            "m.unknown_transaction" => CancelCode::UnknownTransaction,
+            "m.unknown_method" => CancelCode::UnknownMethod,
+            "m.unexpected_message" => CancelCode::UnexpectedMessage,
+            "m.key_mismatch" => CancelCode::KeyMismatch,
+            "m.user_mismatch" => CancelCode::UserMismatch,
+            "m.invalid_message" => CancelCode::InvalidMessage,
+            "m.accepted" => CancelCode::Accepted,
+            cancel_code => CancelCode::Custom(cancel_code.to_string()),
+        }
+    }
+}
+
+impl Serialize for CancelCode {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+
+impl<'de> Deserialize<'de> for CancelCode {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct CancelCodeVisitor;
+
+        impl<'de> Visitor<'de> for CancelCodeVisitor {
+            type Value = CancelCode;
+
+            fn expecting(&self, formatter: &mut Formatter<'_>) -> FmtResult {
+                write!(formatter, "an `m.key.verification.cancel` code as a string")
+            }
+
+            fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+            where
+                E: SerdeError,
+            {
+                Ok(CancelCode::from(v))
+            }
+        }
+
+        deserializer.deserialize_str(CancelCodeVisitor)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use serde_json::{from_str, to_string};
+
+    use super::CancelCode;
+
+    #[test]
+    fn cancel_codes_serialize_to_display_form() {
+        assert_eq!(to_string(&CancelCode::User).unwrap(), r#""m.user""#);
+    }
+
+    #[test]
+    fn custom_cancel_codes_serialize_to_display_form() {
+        assert_eq!(
+            to_string(&CancelCode::Custom("io.ruma.test".to_string())).unwrap(),
+            r#""io.ruma.test""#
+        );
+    }
+
+    #[test]
+    fn cancel_codes_deserialize_from_display_form() {
+        assert_eq!(
+            from_str::<CancelCode>(r#""m.user""#).unwrap(),
+            CancelCode::User
+        );
+    }
+
+    #[test]
+    fn custom_cancel_codes_deserialize_from_display_form() {
+        assert_eq!(
+            from_str::<CancelCode>(r#""io.ruma.test""#).unwrap(),
+            CancelCode::Custom("io.ruma.test".to_string())
+        )
+    }
+}
diff --git a/src/key/verification/key.rs b/src/key/verification/key.rs
new file mode 100644
index 00000000..07cb1067
--- /dev/null
+++ b/src/key/verification/key.rs
@@ -0,0 +1,22 @@
+//! Types for the *m.key.verification.key* event.
+
+use serde::{Deserialize, Serialize};
+
+event! {
+    /// Sends the ephemeral public key for a device to the partner device.
+    ///
+    /// Typically sent as a to-device event.
+    pub struct KeyEvent(KeyEventContent) {}
+}
+
+/// The payload of an *m.key.verification.key* event.
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub struct KeyEventContent {
+    /// An opaque identifier for the verification process.
+    ///
+    /// Must be the same as the one used for the *m.key.verification.start* message.
+    pub transaction_id: String,
+
+    /// The device's ephemeral public key, encoded as unpadded Base64.
+    pub key: String,
+}
diff --git a/src/key/verification/mac.rs b/src/key/verification/mac.rs
new file mode 100644
index 00000000..8a8b0df1
--- /dev/null
+++ b/src/key/verification/mac.rs
@@ -0,0 +1,29 @@
+//! Types for the *m.key.verification.mac* event.
+
+use ruma_signatures::SignatureSet;
+use serde::{Deserialize, Serialize};
+
+event! {
+    /// Sends the MAC of a device's key to the partner device.
+    ///
+    /// Typically sent as a to-device event.
+    pub struct MacEvent(MacEventContent) {}
+}
+
+/// The payload for an *m.key.verification.mac* event.
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub struct MacEventContent {
+    /// An opaque identifier for the verification process.
+    ///
+    /// Must be the same as the one used for the *m.key.verification.start* message.
+    pub transaction_id: String,
+
+    /// A map of the key ID to the MAC of the key, using the algorithm in the verification process.
+    ///
+    /// The MAC is encoded as unpadded Base64.
+    pub mac: SignatureSet,
+
+    /// The MAC of the comma-separated, sorted, list of key IDs given in the `mac` property, encoded
+    /// as unpadded Base64.
+    pub keys: String,
+}
diff --git a/src/key/verification/request.rs b/src/key/verification/request.rs
new file mode 100644
index 00000000..7d1a3a4f
--- /dev/null
+++ b/src/key/verification/request.rs
@@ -0,0 +1,34 @@
+//! Types for the *m.key.verification.request* event.
+
+use ruma_identifiers::DeviceId;
+use serde::{Deserialize, Serialize};
+
+use super::VerificationMethod;
+
+event! {
+    /// Requests a key verification with another user's devices.
+    ///
+    /// Typically sent as a to-device event.
+    pub struct RequestEvent(RequestEventContent) {}
+}
+
+/// The payload of an *m.key.verification.request* event.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct RequestEventContent {
+    /// The device ID which is initiating the request.
+    pub from_device: DeviceId,
+
+    /// An opaque identifier for the verification request.
+    ///
+    /// Must be unique with respect to the devices involved.
+    pub transaction_id: String,
+
+    /// The verification methods supported by the sender.
+    pub methods: Vec<VerificationMethod>,
+
+    /// The POSIX timestamp in milliseconds for when the request was made.
+    ///
+    /// If the request is in the future by more than 5 minutes or more than 10 minutes in the past,
+    /// the message should be ignored by the receiver.
+    pub timestamp: u64,
+}
diff --git a/src/key/verification/start.rs b/src/key/verification/start.rs
new file mode 100644
index 00000000..c6b28b7f
--- /dev/null
+++ b/src/key/verification/start.rs
@@ -0,0 +1,173 @@
+//! Types for the *m.key.verification.start* event.
+
+use ruma_identifiers::DeviceId;
+use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
+use serde_json::{from_value, Value};
+
+use super::{
+    HashAlgorithm, KeyAgreementProtocol, MessageAuthenticationCode, ShortAuthenticationString,
+    VerificationMethod,
+};
+
+event! {
+    /// Begins an SAS key verification process.
+    ///
+    /// Typically sent as a to-device event.
+    pub struct StartEvent(StartEventContent) {}
+}
+
+/// The payload of an *m.key.verification.start* event.
+#[derive(Clone, Debug, PartialEq)]
+pub enum StartEventContent {
+    /// The *m.sas.v1* verification method.
+    MSasV1(MSasV1Content),
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+/// The payload of an *m.key.verification.start* event using the *m.sas.v1* method.
+#[derive(Clone, Debug, Serialize, PartialEq, Deserialize)]
+pub struct MSasV1Content {
+    /// The device ID which is initiating the process.
+    pub from_device: DeviceId,
+
+    /// An opaque identifier for the verification process.
+    ///
+    /// Must be unique with respect to the devices involved. Must be the same as the
+    /// `transaction_id` given in the *m.key.verification.request* if this process is originating
+    /// from a request.
+    pub transaction_id: String,
+
+    /// The verification method to use.
+    ///
+    /// Must be `m.sas.v1`.
+    pub method: VerificationMethod,
+
+    /// Optional method to use to verify the other user's key with.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub next_method: Option<VerificationMethod>,
+
+    /// The key agreement protocols the sending device understands.
+    ///
+    /// Must include at least `curve25519`.
+    pub key_agreement_protocols: Vec<KeyAgreementProtocol>,
+
+    /// The hash methods the sending device understands.
+    ///
+    /// Must include at least `sha256`.
+    pub hashes: Vec<HashAlgorithm>,
+
+    /// The message authentication codes that the sending device understands.
+    ///
+    /// Must include at least `hkdf-hmac-sha256`.
+    pub message_authentication_codes: Vec<MessageAuthenticationCode>,
+
+    /// The SAS methods the sending device (and the sending device's user) understands.
+    ///
+    /// Must include at least `decimal`. Optionally can include `emoji`.
+    pub short_authentication_string: Vec<ShortAuthenticationString>,
+}
+
+impl Serialize for StartEventContent {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        match *self {
+            StartEventContent::MSasV1(ref content) => content.serialize(serializer),
+            _ => panic!("Attempted to serialize __Nonexhaustive variant."),
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for StartEventContent {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let value: Value = Deserialize::deserialize(deserializer)?;
+
+        let method_value = match value.get("method") {
+            Some(value) => value.clone(),
+            None => return Err(D::Error::missing_field("method")),
+        };
+
+        let method = match from_value::<VerificationMethod>(method_value.clone()) {
+            Ok(method) => method,
+            Err(error) => return Err(D::Error::custom(error.to_string())),
+        };
+
+        match method {
+            VerificationMethod::MSasV1 => {
+                let content = match from_value::<MSasV1Content>(value) {
+                    Ok(content) => content,
+                    Err(error) => return Err(D::Error::custom(error.to_string())),
+                };
+
+                Ok(StartEventContent::MSasV1(content))
+            }
+            VerificationMethod::__Nonexhaustive => Err(D::Error::custom(
+                "Attempted to deserialize __Nonexhaustive variant.",
+            )),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use serde_json::{from_str, to_string};
+
+    use super::{
+        HashAlgorithm, KeyAgreementProtocol, MSasV1Content, MessageAuthenticationCode,
+        ShortAuthenticationString, StartEventContent, VerificationMethod,
+    };
+
+    #[test]
+    fn serializtion() {
+        let key_verification_start_content = StartEventContent::MSasV1(MSasV1Content {
+            from_device: "123".to_string(),
+            transaction_id: "456".to_string(),
+            method: VerificationMethod::MSasV1,
+            next_method: None,
+            hashes: vec![HashAlgorithm::Sha256],
+            key_agreement_protocols: vec![KeyAgreementProtocol::Curve25519],
+            message_authentication_codes: vec![MessageAuthenticationCode::HkdfHmacSha256],
+            short_authentication_string: vec![ShortAuthenticationString::Decimal],
+        });
+
+        assert_eq!(
+            to_string(&key_verification_start_content).unwrap(),
+            r#"{"from_device":"123","transaction_id":"456","method":"m.sas.v1","key_agreement_protocols":["curve25519"],"hashes":["sha256"],"message_authentication_codes":["hkdf-hmac-sha256"],"short_authentication_string":["decimal"]}"#
+        );
+    }
+
+    #[test]
+    fn deserialization() {
+        let key_verification_start_content = StartEventContent::MSasV1(MSasV1Content {
+            from_device: "123".to_string(),
+            transaction_id: "456".to_string(),
+            method: VerificationMethod::MSasV1,
+            next_method: None,
+            hashes: vec![HashAlgorithm::Sha256],
+            key_agreement_protocols: vec![KeyAgreementProtocol::Curve25519],
+            message_authentication_codes: vec![MessageAuthenticationCode::HkdfHmacSha256],
+            short_authentication_string: vec![ShortAuthenticationString::Decimal],
+        });
+
+        assert_eq!(
+            from_str::<StartEventContent>(
+                r#"{"from_device":"123","transaction_id":"456","method":"m.sas.v1","hashes":["sha256"],"key_agreement_protocols":["curve25519"],"message_authentication_codes":["hkdf-hmac-sha256"],"short_authentication_string":["decimal"]}"#
+            )
+            .unwrap(),
+            key_verification_start_content
+        );
+    }
+
+    #[test]
+    fn deserialization_failure() {
+        assert!(from_str::<StartEventContent>(r#"{"from_device":"123"}"#).is_err());
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 99bc6880..218e7f0e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -118,11 +118,16 @@ pub mod collections {
     pub mod only;
 }
 pub mod direct;
+pub mod dummy;
+pub mod forwarded_room_key;
 pub mod fully_read;
 pub mod ignored_user_list;
+pub mod key;
 pub mod presence;
 pub mod receipt;
 pub mod room;
+pub mod room_key;
+pub mod room_key_request;
 pub mod sticker;
 pub mod stripped;
 pub mod tag;
@@ -411,6 +416,84 @@ impl<'de> Deserialize<'de> for EventType {
     }
 }
 
+/// An encryption algorithm to be used to encrypt messages sent to a room.
+#[derive(Clone, Debug, PartialEq)]
+pub enum Algorithm {
+    /// Olm version 1 using Curve25519, AES-256, and SHA-256.
+    OlmV1Curve25519AesSha2,
+
+    /// Megolm version 1 using AES-256 and SHA-256.
+    MegolmV1AesSha2,
+
+    /// Any algorithm that is not part of the specification.
+    Custom(String),
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Display for Algorithm {
+    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        let algorithm_str = match *self {
+            Algorithm::OlmV1Curve25519AesSha2 => "m.olm.v1.curve25519-aes-sha2",
+            Algorithm::MegolmV1AesSha2 => "m.megolm.v1.aes-sha2",
+            Algorithm::Custom(ref algorithm) => algorithm,
+            Algorithm::__Nonexhaustive => {
+                panic!("__Nonexhaustive enum variant is not intended for use.")
+            }
+        };
+
+        write!(f, "{}", algorithm_str)
+    }
+}
+
+impl<'a> From<&'a str> for Algorithm {
+    fn from(s: &'a str) -> Algorithm {
+        match s {
+            "m.olm.v1.curve25519-aes-sha2" => Algorithm::OlmV1Curve25519AesSha2,
+            "m.megolm.v1.aes-sha2" => Algorithm::MegolmV1AesSha2,
+            algorithm => Algorithm::Custom(algorithm.to_string()),
+        }
+    }
+}
+
+impl Serialize for Algorithm {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+
+impl<'de> Deserialize<'de> for Algorithm {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct CancelCodeVisitor;
+
+        impl<'de> Visitor<'de> for CancelCodeVisitor {
+            type Value = Algorithm;
+
+            fn expecting(&self, formatter: &mut Formatter<'_>) -> FmtResult {
+                write!(formatter, "an encryption algorithm code as a string")
+            }
+
+            fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+            where
+                E: SerdeError,
+            {
+                Ok(Algorithm::from(v))
+            }
+        }
+
+        deserializer.deserialize_str(CancelCodeVisitor)
+    }
+}
+
 /// Serde deserialization decorator to map empty Strings to None,
 /// and forward non-empty Strings to the Deserialize implementation for T.
 /// Useful for the typical
@@ -445,7 +528,7 @@ fn default_true() -> bool {
 mod tests {
     use serde_json::{from_str, to_string};
 
-    use super::EventType;
+    use super::{Algorithm, EventType};
 
     #[test]
     fn event_types_serialize_to_display_form() {
@@ -478,4 +561,36 @@ mod tests {
             EventType::Custom("io.ruma.test".to_string())
         )
     }
+
+    #[test]
+    fn algorithms_serialize_to_display_form() {
+        assert_eq!(
+            to_string(&Algorithm::MegolmV1AesSha2).unwrap(),
+            r#""m.megolm.v1.aes-sha2""#
+        );
+    }
+
+    #[test]
+    fn custom_algorithms_serialize_to_display_form() {
+        assert_eq!(
+            to_string(&Algorithm::Custom("io.ruma.test".to_string())).unwrap(),
+            r#""io.ruma.test""#
+        );
+    }
+
+    #[test]
+    fn algorithms_deserialize_from_display_form() {
+        assert_eq!(
+            from_str::<Algorithm>(r#""m.megolm.v1.aes-sha2""#).unwrap(),
+            Algorithm::MegolmV1AesSha2
+        );
+    }
+
+    #[test]
+    fn custom_algorithms_deserialize_from_display_form() {
+        assert_eq!(
+            from_str::<Algorithm>(r#""io.ruma.test""#).unwrap(),
+            Algorithm::Custom("io.ruma.test".to_string())
+        )
+    }
 }
diff --git a/src/room.rs b/src/room.rs
index 45398176..28073a50 100644
--- a/src/room.rs
+++ b/src/room.rs
@@ -10,6 +10,8 @@ pub mod aliases;
 pub mod avatar;
 pub mod canonical_alias;
 pub mod create;
+pub mod encrypted;
+pub mod encryption;
 pub mod guest_access;
 pub mod history_visibility;
 pub mod join_rules;
diff --git a/src/room/encrypted.rs b/src/room/encrypted.rs
new file mode 100644
index 00000000..4bf5a535
--- /dev/null
+++ b/src/room/encrypted.rs
@@ -0,0 +1,184 @@
+//! Types for the *m.room.encrypted* event.
+
+use ruma_identifiers::DeviceId;
+use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
+use serde_json::{from_value, Value};
+
+use crate::Algorithm;
+
+room_event! {
+    /// This event type is used when sending encrypted events.
+    ///
+    /// This type is to be used within a room. For a to-device event, use `EncryptedEventContent`
+    /// directly.
+    pub struct EncryptedEvent(EncryptedEventContent) {}
+}
+
+/// The payload of an *m.room.encrypted* event.
+#[derive(Clone, Debug, PartialEq)]
+pub enum EncryptedEventContent {
+    /// An event encrypted with *m.olm.v1.curve25519-aes-sha2*.
+    OlmV1Curve25519AesSha2(OlmV1Curve25519AesSha2Content),
+
+    /// An event encrypted with *m.megolm.v1.aes-sha2*.
+    MegolmV1AesSha2(MegolmV1AesSha2Content),
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+/// The payload of an *m.room.encrypted* event using the *m.olm.v1.curve25519-aes-sha2* algorithm.
+#[derive(Clone, Debug, Serialize, PartialEq, Deserialize)]
+pub struct OlmV1Curve25519AesSha2Content {
+    /// The encryption algorithm used to encrypt this event.
+    pub algorithm: Algorithm,
+
+    /// The encrypted content of the event.
+    pub ciphertext: CiphertextInfo,
+
+    /// The Curve25519 key of the sender.
+    pub sender_key: String,
+}
+
+/// A map from the recipient Curve25519 identity key to ciphertext information.
+///
+/// Used for messages encrypted with the *m.olm.v1.curve25519-aes-sha2* algorithm.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct CiphertextInfo {
+    /// The encrypted payload.
+    pub body: String,
+
+    /// The Olm message type.
+    #[serde(rename = "type")]
+    pub message_type: u64,
+}
+
+/// The payload of an *m.room.encrypted* event using the *m.megolm.v1.aes-sha2* algorithm.
+#[derive(Clone, Debug, Serialize, PartialEq, Deserialize)]
+pub struct MegolmV1AesSha2Content {
+    /// The encryption algorithm used to encrypt this event.
+    pub algorithm: Algorithm,
+
+    /// The encrypted content of the event.
+    pub ciphertext: String,
+
+    /// The Curve25519 key of the sender.
+    pub sender_key: String,
+
+    /// The ID of the sending device.
+    pub device_id: DeviceId,
+
+    /// The ID of the session used to encrypt the message.
+    pub session_id: String,
+}
+
+impl Serialize for EncryptedEventContent {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        match *self {
+            EncryptedEventContent::OlmV1Curve25519AesSha2(ref content) => {
+                content.serialize(serializer)
+            }
+            EncryptedEventContent::MegolmV1AesSha2(ref content) => content.serialize(serializer),
+            _ => panic!("Attempted to serialize __Nonexhaustive variant."),
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for EncryptedEventContent {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let value: Value = Deserialize::deserialize(deserializer)?;
+
+        let method_value = match value.get("algorithm") {
+            Some(value) => value.clone(),
+            None => return Err(D::Error::missing_field("algorithm")),
+        };
+
+        let method = match from_value::<Algorithm>(method_value.clone()) {
+            Ok(method) => method,
+            Err(error) => return Err(D::Error::custom(error.to_string())),
+        };
+
+        match method {
+            Algorithm::OlmV1Curve25519AesSha2 => {
+                let content = match from_value::<OlmV1Curve25519AesSha2Content>(value) {
+                    Ok(content) => content,
+                    Err(error) => return Err(D::Error::custom(error.to_string())),
+                };
+
+                Ok(EncryptedEventContent::OlmV1Curve25519AesSha2(content))
+            }
+            Algorithm::MegolmV1AesSha2 => {
+                let content = match from_value::<MegolmV1AesSha2Content>(value) {
+                    Ok(content) => content,
+                    Err(error) => return Err(D::Error::custom(error.to_string())),
+                };
+
+                Ok(EncryptedEventContent::MegolmV1AesSha2(content))
+            }
+            Algorithm::Custom(_) => Err(D::Error::custom(
+                "Custom algorithms are not supported by `EncryptedEventContent`.",
+            )),
+            Algorithm::__Nonexhaustive => Err(D::Error::custom(
+                "Attempted to deserialize __Nonexhaustive variant.",
+            )),
+        }
+    }
+}
+#[cfg(test)]
+mod tests {
+    use serde_json::{from_str, to_string};
+
+    use super::{Algorithm, EncryptedEventContent, MegolmV1AesSha2Content};
+
+    #[test]
+    fn serializtion() {
+        let key_verification_start_content =
+            EncryptedEventContent::MegolmV1AesSha2(MegolmV1AesSha2Content {
+                algorithm: Algorithm::MegolmV1AesSha2,
+                ciphertext: "ciphertext".to_string(),
+                sender_key: "sender_key".to_string(),
+                device_id: "device_id".to_string(),
+                session_id: "session_id".to_string(),
+            });
+
+        assert_eq!(
+            to_string(&key_verification_start_content).unwrap(),
+            r#"{"algorithm":"m.megolm.v1.aes-sha2","ciphertext":"ciphertext","sender_key":"sender_key","device_id":"device_id","session_id":"session_id"}"#
+        );
+    }
+
+    #[test]
+    fn deserialization() {
+        let key_verification_start_content =
+            EncryptedEventContent::MegolmV1AesSha2(MegolmV1AesSha2Content {
+                algorithm: Algorithm::MegolmV1AesSha2,
+                ciphertext: "ciphertext".to_string(),
+                sender_key: "sender_key".to_string(),
+                device_id: "device_id".to_string(),
+                session_id: "session_id".to_string(),
+            });
+
+        assert_eq!(
+            from_str::<EncryptedEventContent>(
+                r#"{"algorithm":"m.megolm.v1.aes-sha2","ciphertext":"ciphertext","sender_key":"sender_key","device_id":"device_id","session_id":"session_id"}"#
+            )
+            .unwrap(),
+            key_verification_start_content
+        );
+    }
+
+    #[test]
+    fn deserialization_failure() {
+        assert!(
+            from_str::<EncryptedEventContent>(r#"{"algorithm":"m.megolm.v1.aes-sha2"}"#).is_err()
+        );
+    }
+}
diff --git a/src/room/encryption.rs b/src/room/encryption.rs
new file mode 100644
index 00000000..2a39ebdf
--- /dev/null
+++ b/src/room/encryption.rs
@@ -0,0 +1,29 @@
+//! Types for the *m.room.encryption* event.
+
+use serde::{Deserialize, Serialize};
+
+use crate::Algorithm;
+
+state_event! {
+    /// Defines how messages sent in this room should be encrypted.
+    pub struct EncryptionEvent(EncryptionEventContent) {}
+}
+
+/// The payload of an *m.room.encryption* event.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct EncryptionEventContent {
+    /// The encryption algorithm to be used to encrypt messages sent in this room.
+    ///
+    /// Must be `m.megolm.v1.aes-sha2`.
+    pub algorithm: Algorithm,
+
+    /// How long the session should be used before changing it.
+    ///
+    /// 604800000 (a week) is the recommended default.
+    pub rotation_period_ms: Option<u64>,
+
+    /// How many messages should be sent before changing the session.
+    ///
+    /// 100 is the recommended default.
+    pub rotation_period_msgs: Option<u64>,
+}
diff --git a/src/room_key.rs b/src/room_key.rs
new file mode 100644
index 00000000..cfebcd93
--- /dev/null
+++ b/src/room_key.rs
@@ -0,0 +1,31 @@
+//! Types for the *m.room_key* event.
+
+use ruma_identifiers::RoomId;
+use serde::{Deserialize, Serialize};
+
+use super::Algorithm;
+
+event! {
+    /// This event type is used to exchange keys for end-to-end encryption.
+    ///
+    /// Typically it is encrypted as an *m.room.encrypted* event, then sent as a to-device event.
+    pub struct RoomKeyEvent(RoomKeyEventContent) {}
+}
+
+/// The payload of an *m.room_key* event.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct RoomKeyEventContent {
+    /// The encryption algorithm the key in this event is to be used with.
+    ///
+    /// Must be `m.megolm.v1.aes-sha2`.
+    pub algorithm: Algorithm,
+
+    /// The room where the key is used.
+    pub room_id: RoomId,
+
+    /// The ID of the session that the key is for.
+    pub session_id: String,
+
+    /// The key to be exchanged.
+    pub session_key: String,
+}
diff --git a/src/room_key_request.rs b/src/room_key_request.rs
new file mode 100644
index 00000000..8aadcce5
--- /dev/null
+++ b/src/room_key_request.rs
@@ -0,0 +1,73 @@
+//! Types for the *m.room_key_request* event.
+
+use ruma_identifiers::{DeviceId, RoomId};
+use serde::{Deserialize, Serialize};
+
+use super::Algorithm;
+
+event! {
+    /// This event type is used to request keys for end-to-end encryption.
+    ///
+    /// It is sent as an unencrypted to-device event.
+    pub struct RoomKeyRequestEvent(RoomKeyRequestEventContent) {}
+}
+
+/// The payload of an *m.room_key_request* event.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct RoomKeyRequestEventContent {
+    /// Whether this is a new key request or a cancellation of a previous request.
+    pub action: Action,
+
+    /// Information about the requested key.
+    ///
+    /// Required when action is `request`.
+    pub body: Option<RequestedKeyInfo>,
+
+    /// ID of the device requesting the key.
+    pub requesting_device_id: DeviceId,
+
+    /// A random string uniquely identifying the request for a key.
+    ///
+    /// If the key is requested multiple times, it should be reused. It should also reused in order
+    /// to cancel a request.
+    pub request_id: String,
+}
+
+/// A new key request or a cancellation of a previous request.
+#[derive(Clone, Copy, Deserialize, Debug, PartialEq, Serialize)]
+pub enum Action {
+    /// Request a key.
+    Request,
+
+    /// Cancel a request for a key.
+    CancelRequest,
+
+    /// Additional variants may be added in the future and will not be considered breaking changes
+    /// to `ruma-events`.
+    #[doc(hidden)]
+    #[serde(skip)]
+    __Nonexhaustive,
+}
+
+impl_enum! {
+    Action {
+        Request => "request",
+        CancelRequest => "cancel_request",
+    }
+}
+
+/// Information about a requested key.
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct RequestedKeyInfo {
+    /// The encryption algorithm the requested key in this event is to be used with.
+    pub algorithm: Algorithm,
+
+    /// The room where the key is used.
+    pub room_id: RoomId,
+
+    /// The Curve25519 key of the device which initiated the session originally.
+    pub sender_key: String,
+
+    /// The ID of the session that the key is for.
+    pub session_id: String,
+}