diff --git a/services/backup/docker-server/contents/server/src/DatabaseEntities/BackupItem.h b/services/backup/docker-server/contents/server/src/DatabaseEntities/BackupItem.h
index 82c7b8112..92f0b9e87 100644
--- a/services/backup/docker-server/contents/server/src/DatabaseEntities/BackupItem.h
+++ b/services/backup/docker-server/contents/server/src/DatabaseEntities/BackupItem.h
@@ -1,69 +1,80 @@
 #pragma once
 
 #include "Item.h"
 
 #include <string>
 #include <vector>
 
 namespace comm {
 namespace network {
 namespace database {
 
 /**
+ * backup - backups assigned to users along with the data necessary to
+ * decrypt
+ *  `created` - when the backup was created. This is a search key because
+ *    we want to be able to perform effective queries based on this info
+ *    (for example get me the latest backup, get me backup from some day)
+ *  `attachmentHolders` - this is a list of attachment references
+ *  `recoveryData` - data serialized with protobuf which is described by
+ *    one of the following structures:
+ *      { authType: 'password', pakePasswordCiphertext: string, nonce: string }
+ *      { authType: 'wallet', walletAddress: string, rawMessage: string }
+ *
  * this class is used for representing two things: the rows in the main table,
  * and also the rows in the secondary index
  *
  * Needs userID(pk)-created(sk)-index that projects:
  *  userID
  *  backupID
  *  created
  *  recoveryData
  */
 class BackupItem : public Item {
 
   std::string userID;
   std::string backupID;
   uint64_t created;
   std::string recoveryData;
   std::string compactionHolder;
   std::vector<std::string> attachmentHolders;
 
   void validate() const override;
 
 public:
   static std::string tableName;
   static const std::string FIELD_USER_ID;
   static const std::string FIELD_BACKUP_ID;
   static const std::string FIELD_CREATED;
   static const std::string FIELD_RECOVERY_DATA;
   static const std::string FIELD_COMPACTION_HOLDER;
   static const std::string FIELD_ATTACHMENT_HOLDERS;
 
   BackupItem() {
   }
   BackupItem(
       std::string userID,
       std::string backupID,
       uint64_t created,
       std::string recoveryData,
       std::string compactionHolder,
       std::vector<std::string> attachmentHolders);
   BackupItem(const AttributeValues &itemFromDB);
 
   void assignItemFromDatabase(const AttributeValues &itemFromDB) override;
 
   std::string getTableName() const override;
   PrimaryKey getPrimaryKey() const override;
   PrimaryKeyValue getPrimaryKeyValue() const override;
 
   std::string getUserID() const;
   std::string getBackupID() const;
   uint64_t getCreated() const;
   std::string getRecoveryData() const;
   std::string getCompactionHolder() const;
   std::vector<std::string> getAttachmentHolders() const;
 };
 
 } // namespace database
 } // namespace network
 } // namespace comm
diff --git a/services/backup/docker-server/contents/server/src/DatabaseEntities/LogItem.h b/services/backup/docker-server/contents/server/src/DatabaseEntities/LogItem.h
index 70e23f025..cbc47efeb 100644
--- a/services/backup/docker-server/contents/server/src/DatabaseEntities/LogItem.h
+++ b/services/backup/docker-server/contents/server/src/DatabaseEntities/LogItem.h
@@ -1,55 +1,63 @@
 #pragma once
 
 #include "Item.h"
 
 #include <string>
 #include <vector>
 
 namespace comm {
 namespace network {
 namespace database {
 
+/*
+ * log - a single log record
+ *  `backupID` - id of the backup that this log is assigned to
+ *  `value` - either the value itself which is a dump of a single operation (if
+ * `persistedInBlob` is false) or the holder to blob (if `persistedInBlob` is
+ * true)
+ *  `attachmentHolders` - this is a list of attachment references
+ */
 class LogItem : public Item {
 
   std::string backupID;
   std::string logID;
   bool persistedInBlob;
   std::string value;
   std::vector<std::string> attachmentHolders;
 
   void validate() const override;
 
 public:
   static std::string tableName;
   static const std::string FIELD_BACKUP_ID;
   static const std::string FIELD_LOG_ID;
   static const std::string FIELD_PERSISTED_IN_BLOB;
   static const std::string FIELD_VALUE;
   static const std::string FIELD_ATTACHMENT_HOLDERS;
 
   LogItem() {
   }
   LogItem(
       const std::string backupID,
       const std::string logID,
       const bool persistedInBlob,
       const std::string value,
       std::vector<std::string> attachmentHolders);
   LogItem(const AttributeValues &itemFromDB);
 
   void assignItemFromDatabase(const AttributeValues &itemFromDB) override;
 
   std::string getTableName() const override;
   PrimaryKey getPrimaryKey() const override;
   PrimaryKeyValue getPrimaryKeyValue() const override;
 
   std::string getBackupID() const;
   std::string getLogID() const;
   bool getPersistedInBlob() const;
   std::string getValue() const;
   std::vector<std::string> getAttachmentHolders() const;
 };
 
 } // namespace database
 } // namespace network
 } // namespace comm