diff --git a/services/identity/src/constants.rs b/services/identity/src/constants.rs
index 7d00f429b..1300db0da 100644
--- a/services/identity/src/constants.rs
+++ b/services/identity/src/constants.rs
@@ -1,46 +1,48 @@
 // Secrets
 
 pub const SECRETS_DIRECTORY: &str = "secrets";
 pub const SECRETS_FILE_NAME: &str = "secret_key";
 pub const SECRETS_FILE_EXTENSION: &str = "txt";
 
 // DynamoDB
 
 pub const USERS_TABLE: &str = "identity-users";
 pub const USERS_TABLE_PARTITION_KEY: &str = "userID";
 pub const USERS_TABLE_REGISTRATION_ATTRIBUTE: &str = "pakeRegistrationData";
 pub const USERS_TABLE_USERNAME_ATTRIBUTE: &str = "username";
 pub const USERS_TABLE_DEVICES_ATTRIBUTE: &str = "devices";
+pub const USERS_TABLE_DEVICE_ATTRIBUTE_NAME: &str = "device";
 pub const USERS_TABLE_DEVICES_MAP_ATTRIBUTE_NAME: &str = "signingPublicKey";
 pub const USERS_TABLE_WALLET_ADDRESS_ATTRIBUTE: &str = "walletAddress";
 pub const USERS_TABLE_USERNAME_INDEX: &str = "username-index";
 pub const USERS_TABLE_WALLET_ADDRESS_INDEX: &str = "walletAddress-index";
+pub const USERS_TABLE_INITIALIZATION_INFO: &str = "initializationInfo";
 
 pub const ACCESS_TOKEN_TABLE: &str = "identity-tokens";
 pub const ACCESS_TOKEN_TABLE_PARTITION_KEY: &str = "userID";
 pub const ACCESS_TOKEN_SORT_KEY: &str = "signingPublicKey";
 pub const ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE: &str = "created";
 pub const ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE: &str = "authType";
 pub const ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE: &str = "valid";
 pub const ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE: &str = "token";
 
 pub const NONCE_TABLE: &str = "identity-nonces";
 pub const NONCE_TABLE_PARTITION_KEY: &str = "nonce";
 pub const NONCE_TABLE_CREATED_ATTRIBUTE: &str = "created";
 
 // Tokio
 
 pub const MPSC_CHANNEL_BUFFER_CAPACITY: usize = 1;
 pub const IDENTITY_SERVICE_SOCKET_ADDR: &str = "[::]:50051";
 
 // Token
 
 pub const ACCESS_TOKEN_LENGTH: usize = 512;
 
 // Temporary config
 
 pub const AUTH_TOKEN: &str = "COMM_IDENTITY_SERVICE_AUTH_TOKEN";
 
 // Nonce
 
 pub const NONCE_LENGTH: usize = 17;
diff --git a/services/identity/src/database.rs b/services/identity/src/database.rs
index 623e99499..5f1f412f1 100644
--- a/services/identity/src/database.rs
+++ b/services/identity/src/database.rs
@@ -1,671 +1,746 @@
 use std::collections::HashMap;
 use std::fmt::{Display, Formatter, Result as FmtResult};
 use std::sync::Arc;
 
 use aws_sdk_dynamodb::model::AttributeValue;
 use aws_sdk_dynamodb::output::{
   DeleteItemOutput, GetItemOutput, PutItemOutput, QueryOutput, UpdateItemOutput,
 };
 use aws_sdk_dynamodb::types::Blob;
 use aws_sdk_dynamodb::{Client, Error as DynamoDBError};
 use aws_types::sdk_config::SdkConfig;
 use chrono::{DateTime, Utc};
 use opaque_ke::{errors::ProtocolError, ServerRegistration};
 use tracing::{debug, error, info, warn};
 
 use crate::constants::{
   ACCESS_TOKEN_SORT_KEY, ACCESS_TOKEN_TABLE,
   ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE, ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE,
   ACCESS_TOKEN_TABLE_PARTITION_KEY, ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE,
   ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE, NONCE_TABLE,
   NONCE_TABLE_CREATED_ATTRIBUTE, NONCE_TABLE_PARTITION_KEY, USERS_TABLE,
   USERS_TABLE_DEVICES_ATTRIBUTE, USERS_TABLE_DEVICES_MAP_ATTRIBUTE_NAME,
+  USERS_TABLE_DEVICE_ATTRIBUTE_NAME, USERS_TABLE_INITIALIZATION_INFO,
   USERS_TABLE_PARTITION_KEY, USERS_TABLE_REGISTRATION_ATTRIBUTE,
   USERS_TABLE_USERNAME_ATTRIBUTE, USERS_TABLE_USERNAME_INDEX,
   USERS_TABLE_WALLET_ADDRESS_ATTRIBUTE, USERS_TABLE_WALLET_ADDRESS_INDEX,
 };
 use crate::nonce::NonceData;
 use crate::token::{AccessTokenData, AuthType};
 use comm_opaque::Cipher;
 
 #[derive(Clone)]
 pub struct DatabaseClient {
   client: Arc<Client>,
 }
 
 impl DatabaseClient {
   pub fn new(aws_config: &SdkConfig) -> Self {
     DatabaseClient {
       client: Arc::new(Client::new(aws_config)),
     }
   }
 
   pub async fn get_pake_registration(
     &self,
     user_id: String,
   ) -> Result<Option<ServerRegistration<Cipher>>, Error> {
     match self.get_item_from_users_table(&user_id).await {
       Ok(GetItemOutput {
         item: Some(mut item),
         ..
       }) => parse_registration_data_attribute(
         item.remove(USERS_TABLE_REGISTRATION_ATTRIBUTE),
       )
       .map(Some)
       .map_err(Error::Attribute),
       Ok(_) => {
         info!(
           "No item found for user {} in PAKE registration table",
           user_id
         );
         Ok(None)
       }
       Err(e) => {
         error!(
           "DynamoDB client failed to get registration data for user {}: {}",
           user_id, e
         );
         Err(e)
       }
     }
   }
 
+  pub async fn get_session_initialization_info(
+    &self,
+    user_id: &str,
+  ) -> Result<Option<HashMap<String, HashMap<String, String>>>, Error> {
+    match self.get_item_from_users_table(user_id).await {
+      Ok(GetItemOutput {
+        item: Some(mut item),
+        ..
+      }) => parse_devices_attribute(item.remove(USERS_TABLE_DEVICES_ATTRIBUTE))
+        .map(Some)
+        .map_err(Error::Attribute),
+      Ok(_) => {
+        info!("No item found for user {} in users table", user_id);
+        Ok(None)
+      }
+      Err(e) => {
+        error!(
+          "DynamoDB client failed to get session initialization info for user {}: {}",
+          user_id, e
+        );
+        Err(e)
+      }
+    }
+  }
+
   pub async fn update_users_table(
     &self,
     user_id: String,
     signing_public_key: Option<String>,
     registration: Option<ServerRegistration<Cipher>>,
     username: Option<String>,
   ) -> Result<UpdateItemOutput, Error> {
     let mut update_expression_parts = Vec::new();
     let mut expression_attribute_names = HashMap::new();
     let mut expression_attribute_values = HashMap::new();
     if let Some(reg) = registration {
       update_expression_parts
         .push(format!("{} = :r", USERS_TABLE_REGISTRATION_ATTRIBUTE));
       expression_attribute_values.insert(
         ":r".to_string(),
         AttributeValue::B(Blob::new(reg.serialize())),
       );
     };
     if let Some(username) = username {
       update_expression_parts
         .push(format!("{} = :u", USERS_TABLE_USERNAME_ATTRIBUTE));
       expression_attribute_values
         .insert(":u".to_string(), AttributeValue::S(username));
     };
     if let Some(public_key) = signing_public_key {
       update_expression_parts.push(format!(
         "{}.#{} = :k",
         USERS_TABLE_DEVICES_ATTRIBUTE, USERS_TABLE_DEVICES_MAP_ATTRIBUTE_NAME,
       ));
       expression_attribute_names.insert(
         format!("#{}", USERS_TABLE_DEVICES_MAP_ATTRIBUTE_NAME),
         public_key,
       );
       expression_attribute_values
         .insert(":k".to_string(), AttributeValue::M(HashMap::new()));
     };
 
     self
       .client
       .update_item()
       .table_name(USERS_TABLE)
       .key(USERS_TABLE_PARTITION_KEY, AttributeValue::S(user_id))
       .update_expression(format!("SET {}", update_expression_parts.join(",")))
       .set_expression_attribute_names(
         if expression_attribute_names.is_empty() {
           None
         } else {
           Some(expression_attribute_names)
         },
       )
       .set_expression_attribute_values(
         if expression_attribute_values.is_empty() {
           None
         } else {
           Some(expression_attribute_values)
         },
       )
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
   pub async fn add_user_to_users_table(
     &self,
     user_id: String,
     registration: ServerRegistration<Cipher>,
     username: String,
     signing_public_key: String,
   ) -> Result<PutItemOutput, Error> {
     let item = HashMap::from([
       (
         USERS_TABLE_PARTITION_KEY.to_string(),
         AttributeValue::S(user_id),
       ),
       (
         USERS_TABLE_USERNAME_ATTRIBUTE.to_string(),
         AttributeValue::S(username),
       ),
       (
         USERS_TABLE_REGISTRATION_ATTRIBUTE.to_string(),
         AttributeValue::B(Blob::new(registration.serialize())),
       ),
       (
         USERS_TABLE_DEVICES_ATTRIBUTE.to_string(),
         AttributeValue::M(HashMap::from([(
           signing_public_key,
           AttributeValue::M(HashMap::new()),
         )])),
       ),
     ]);
 
     self
       .client
       .put_item()
       .table_name(USERS_TABLE)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
   pub async fn delete_user(
     &self,
     user_id: String,
   ) -> Result<DeleteItemOutput, Error> {
     debug!("Attempting to delete user: {}", user_id);
 
     match self
       .client
       .delete_item()
       .table_name(USERS_TABLE)
       .key(
         USERS_TABLE_PARTITION_KEY,
         AttributeValue::S(user_id.clone()),
       )
       .send()
       .await
     {
       Ok(out) => {
         info!("User has been deleted {}", user_id);
         Ok(out)
       }
       Err(e) => {
         error!("DynamoDB client failed to delete user {}", user_id);
         Err(Error::AwsSdk(e.into()))
       }
     }
   }
 
   pub async fn get_access_token_data(
     &self,
     user_id: String,
     signing_public_key: String,
   ) -> Result<Option<AccessTokenData>, Error> {
     let primary_key = create_composite_primary_key(
       (
         ACCESS_TOKEN_TABLE_PARTITION_KEY.to_string(),
         user_id.clone(),
       ),
       (
         ACCESS_TOKEN_SORT_KEY.to_string(),
         signing_public_key.clone(),
       ),
     );
     let get_item_result = self
       .client
       .get_item()
       .table_name(ACCESS_TOKEN_TABLE)
       .set_key(Some(primary_key))
       .consistent_read(true)
       .send()
       .await;
     match get_item_result {
       Ok(GetItemOutput {
         item: Some(mut item),
         ..
       }) => {
         let created = parse_created_attribute(
           item.remove(ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE),
         )?;
         let auth_type = parse_auth_type_attribute(
           item.remove(ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE),
         )?;
         let valid = parse_valid_attribute(
           item.remove(ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE),
         )?;
         let access_token = parse_token_attribute(
           item.remove(ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE),
         )?;
         Ok(Some(AccessTokenData {
           user_id,
           signing_public_key,
           access_token,
           created,
           auth_type,
           valid,
         }))
       }
       Ok(_) => {
         info!(
           "No item found for user {} and signing public key {} in token table",
           user_id, signing_public_key
         );
         Ok(None)
       }
       Err(e) => {
         error!(
           "DynamoDB client failed to get token for user {} with signing public key {}: {}",
           user_id, signing_public_key, e
         );
         Err(Error::AwsSdk(e.into()))
       }
     }
   }
 
   pub async fn put_access_token_data(
     &self,
     access_token_data: AccessTokenData,
   ) -> Result<PutItemOutput, Error> {
     let item = HashMap::from([
       (
         ACCESS_TOKEN_TABLE_PARTITION_KEY.to_string(),
         AttributeValue::S(access_token_data.user_id),
       ),
       (
         ACCESS_TOKEN_SORT_KEY.to_string(),
         AttributeValue::S(access_token_data.signing_public_key),
       ),
       (
         ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE.to_string(),
         AttributeValue::S(access_token_data.access_token),
       ),
       (
         ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE.to_string(),
         AttributeValue::S(access_token_data.created.to_rfc3339()),
       ),
       (
         ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE.to_string(),
         AttributeValue::S(match access_token_data.auth_type {
           AuthType::Password => "password".to_string(),
           AuthType::Wallet => "wallet".to_string(),
         }),
       ),
       (
         ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE.to_string(),
         AttributeValue::Bool(access_token_data.valid),
       ),
     ]);
     self
       .client
       .put_item()
       .table_name(ACCESS_TOKEN_TABLE)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
   pub async fn get_user_id_from_user_info(
     &self,
     user_info: String,
     auth_type: AuthType,
   ) -> Result<Option<String>, Error> {
     let (index, attribute_name) = match auth_type {
       AuthType::Password => {
         (USERS_TABLE_USERNAME_INDEX, USERS_TABLE_USERNAME_ATTRIBUTE)
       }
       AuthType::Wallet => (
         USERS_TABLE_WALLET_ADDRESS_INDEX,
         USERS_TABLE_WALLET_ADDRESS_ATTRIBUTE,
       ),
     };
     match self
       .client
       .query()
       .table_name(USERS_TABLE)
       .index_name(index)
       .key_condition_expression(format!("{} = :u", attribute_name))
       .expression_attribute_values(":u", AttributeValue::S(user_info.clone()))
       .send()
       .await
     {
       Ok(QueryOutput {
         items: Some(mut items),
         ..
       }) => {
         let num_items = items.len();
         if num_items == 0 {
           return Ok(None);
         }
         if num_items > 1 {
           warn!(
             "{} user IDs associated with {} {}: {:?}",
             num_items, attribute_name, user_info, items
           );
         }
         parse_string_attribute(
           USERS_TABLE_PARTITION_KEY,
           items[0].remove(USERS_TABLE_PARTITION_KEY),
         )
         .map(Some)
         .map_err(Error::Attribute)
       }
       Ok(_) => {
         info!(
           "No item found for {} {} in users table",
           attribute_name, user_info
         );
         Ok(None)
       }
       Err(e) => {
         error!(
           "DynamoDB client failed to get user ID from {} {}: {}",
           attribute_name, user_info, e
         );
         Err(Error::AwsSdk(e.into()))
       }
     }
   }
 
   pub async fn get_item_from_users_table(
     &self,
     user_id: &str,
   ) -> Result<GetItemOutput, Error> {
     let primary_key = create_simple_primary_key((
       USERS_TABLE_PARTITION_KEY.to_string(),
       user_id.to_string(),
     ));
     self
       .client
       .get_item()
       .table_name(USERS_TABLE)
       .set_key(Some(primary_key))
       .consistent_read(true)
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
   pub async fn get_users(&self) -> Result<Vec<String>, Error> {
     let scan_output = self
       .client
       .scan()
       .table_name(USERS_TABLE)
       .projection_expression(USERS_TABLE_PARTITION_KEY)
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))?;
 
     let mut result = Vec::new();
     if let Some(attributes) = scan_output.items {
       for mut attribute in attributes {
         let id = parse_string_attribute(
           USERS_TABLE_PARTITION_KEY,
           attribute.remove(USERS_TABLE_PARTITION_KEY),
         )
         .map_err(Error::Attribute)?;
         result.push(id);
       }
     }
     Ok(result)
   }
 
   pub async fn add_nonce_to_nonces_table(
     &self,
     nonce_data: NonceData,
   ) -> Result<PutItemOutput, Error> {
     let item = HashMap::from([
       (
         NONCE_TABLE_PARTITION_KEY.to_string(),
         AttributeValue::S(nonce_data.nonce),
       ),
       (
         NONCE_TABLE_CREATED_ATTRIBUTE.to_string(),
         AttributeValue::S(nonce_data.created.to_rfc3339()),
       ),
     ]);
     self
       .client
       .put_item()
       .table_name(NONCE_TABLE)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 }
 
 #[derive(
   Debug, derive_more::Display, derive_more::From, derive_more::Error,
 )]
 pub enum Error {
   #[display(...)]
   AwsSdk(DynamoDBError),
   #[display(...)]
   Attribute(DBItemError),
 }
 
 #[derive(Debug, derive_more::Error, derive_more::Constructor)]
 pub struct DBItemError {
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
   attribute_error: DBItemAttributeError,
 }
 
 impl Display for DBItemError {
   fn fmt(&self, f: &mut Formatter) -> FmtResult {
     match &self.attribute_error {
       DBItemAttributeError::Missing => {
         write!(f, "Attribute {} is missing", self.attribute_name)
       }
       DBItemAttributeError::IncorrectType => write!(
         f,
         "Value for attribute {} has incorrect type: {:?}",
         self.attribute_name, self.attribute_value
       ),
       error => write!(
         f,
         "Error regarding attribute {} with value {:?}: {}",
         self.attribute_name, self.attribute_value, error
       ),
     }
   }
 }
 
 #[derive(Debug, derive_more::Display, derive_more::Error)]
 pub enum DBItemAttributeError {
   #[display(...)]
   Missing,
   #[display(...)]
   IncorrectType,
   #[display(...)]
   InvalidTimestamp(chrono::ParseError),
   #[display(...)]
   Pake(ProtocolError),
 }
 
 type AttributeName = String;
 
 fn create_simple_primary_key(
   partition_key: (AttributeName, String),
 ) -> HashMap<AttributeName, AttributeValue> {
   HashMap::from([(partition_key.0, AttributeValue::S(partition_key.1))])
 }
 
 fn create_composite_primary_key(
   partition_key: (AttributeName, String),
   sort_key: (AttributeName, String),
 ) -> HashMap<AttributeName, AttributeValue> {
   let mut primary_key = create_simple_primary_key(partition_key);
   primary_key.insert(sort_key.0, AttributeValue::S(sort_key.1));
   primary_key
 }
 
 fn parse_created_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<DateTime<Utc>, DBItemError> {
   if let Some(AttributeValue::S(created)) = &attribute {
     created.parse().map_err(|e| {
       DBItemError::new(
         ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE,
         attribute,
         DBItemAttributeError::InvalidTimestamp(e),
       )
     })
   } else {
     Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     ))
   }
 }
 
 fn parse_auth_type_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<AuthType, DBItemError> {
   if let Some(AttributeValue::S(auth_type)) = &attribute {
     match auth_type.as_str() {
       "password" => Ok(AuthType::Password),
       "wallet" => Ok(AuthType::Wallet),
       _ => Err(DBItemError::new(
         ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE,
         attribute,
         DBItemAttributeError::IncorrectType,
       )),
     }
   } else {
     Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     ))
   }
 }
 
 fn parse_valid_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<bool, DBItemError> {
   match attribute {
     Some(AttributeValue::Bool(valid)) => Ok(valid),
     Some(_) => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE,
       attribute,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_token_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<String, DBItemError> {
   match attribute {
     Some(AttributeValue::S(token)) => Ok(token),
     Some(_) => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE,
       attribute,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_registration_data_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<ServerRegistration<Cipher>, DBItemError> {
   match &attribute {
     Some(AttributeValue::B(server_registration_bytes)) => {
       match ServerRegistration::<Cipher>::deserialize(
         server_registration_bytes.as_ref(),
       ) {
         Ok(server_registration) => Ok(server_registration),
         Err(e) => Err(DBItemError::new(
           USERS_TABLE_REGISTRATION_ATTRIBUTE,
           attribute,
           DBItemAttributeError::Pake(e),
         )),
       }
     }
     Some(_) => Err(DBItemError::new(
       USERS_TABLE_REGISTRATION_ATTRIBUTE,
       attribute,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       USERS_TABLE_REGISTRATION_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
+fn parse_devices_attribute(
+  attribute: Option<AttributeValue>,
+) -> Result<HashMap<String, HashMap<String, String>>, DBItemError> {
+  let mut devices = HashMap::new();
+  let ddb_devices =
+    parse_map_attribute(USERS_TABLE_DEVICES_ATTRIBUTE, attribute)?;
+
+  for (signing_public_key, session_initialization_info) in ddb_devices {
+    let session_initialization_info_map = parse_map_attribute(
+      USERS_TABLE_DEVICE_ATTRIBUTE_NAME,
+      Some(session_initialization_info),
+    )?;
+    let mut inner_hash_map = HashMap::new();
+    for (initialization_component_name, initialization_component_value) in
+      session_initialization_info_map
+    {
+      let initialization_piece_value_string = parse_string_attribute(
+        USERS_TABLE_INITIALIZATION_INFO,
+        Some(initialization_component_value),
+      )?;
+      inner_hash_map.insert(
+        initialization_component_name,
+        initialization_piece_value_string,
+      );
+    }
+    devices.insert(signing_public_key, inner_hash_map);
+  }
+  Ok(devices)
+}
+
+fn parse_map_attribute(
+  attribute_name: &'static str,
+  attribute_value: Option<AttributeValue>,
+) -> Result<HashMap<String, AttributeValue>, DBItemError> {
+  match attribute_value {
+    Some(AttributeValue::M(map)) => Ok(map),
+    Some(_) => Err(DBItemError::new(
+      attribute_name,
+      attribute_value,
+      DBItemAttributeError::IncorrectType,
+    )),
+    None => Err(DBItemError::new(
+      attribute_name,
+      attribute_value,
+      DBItemAttributeError::Missing,
+    )),
+  }
+}
+
 fn parse_string_attribute(
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
 ) -> Result<String, DBItemError> {
   match attribute_value {
     Some(AttributeValue::S(value)) => Ok(value),
     Some(_) => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 #[cfg(test)]
 mod tests {
   use super::*;
 
   #[test]
   fn test_create_simple_primary_key() {
     let partition_key_name = "userID".to_string();
     let partition_key_value = "12345".to_string();
     let partition_key =
       (partition_key_name.clone(), partition_key_value.clone());
     let mut primary_key = create_simple_primary_key(partition_key);
     assert_eq!(primary_key.len(), 1);
     let attribute = primary_key.remove(&partition_key_name);
     assert!(attribute.is_some());
     assert_eq!(attribute, Some(AttributeValue::S(partition_key_value)));
   }
 
   #[test]
   fn test_create_composite_primary_key() {
     let partition_key_name = "userID".to_string();
     let partition_key_value = "12345".to_string();
     let partition_key =
       (partition_key_name.clone(), partition_key_value.clone());
     let sort_key_name = "deviceID".to_string();
     let sort_key_value = "54321".to_string();
     let sort_key = (sort_key_name.clone(), sort_key_value.clone());
     let mut primary_key = create_composite_primary_key(partition_key, sort_key);
     assert_eq!(primary_key.len(), 2);
     let partition_key_attribute = primary_key.remove(&partition_key_name);
     assert!(partition_key_attribute.is_some());
     assert_eq!(
       partition_key_attribute,
       Some(AttributeValue::S(partition_key_value))
     );
     let sort_key_attribute = primary_key.remove(&sort_key_name);
     assert!(sort_key_attribute.is_some());
     assert_eq!(sort_key_attribute, Some(AttributeValue::S(sort_key_value)))
   }
 }