diff --git a/src/blockchain/block.rs b/src/blockchain/block.rs
index 567282a..b090825 100644
--- a/src/blockchain/block.rs
+++ b/src/blockchain/block.rs
@@ -1,6 +1,7 @@
 extern crate serde;
 extern crate serde_json;
 
+use std::cell::RefCell;
 use std::fmt::Debug;
 
 use serde::{Deserialize, Serialize};
@@ -27,7 +28,9 @@ pub struct Block {
     #[serde(default, skip_serializing_if = "Bytes::is_zero")]
     pub signature: Bytes,
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub transaction: Option<Transaction>
+    pub transaction: Option<Transaction>,
+    #[serde(default, skip)]
+    hash_good: RefCell<bool>
 }
 
 impl Block {
@@ -43,7 +46,8 @@ impl Block {
             prev_block_hash,
             hash: Bytes::default(),
             pub_key,
-            signature: Bytes::default()
+            signature: Bytes::default(),
+            hash_good: RefCell::new(false)
         }
     }
 
@@ -60,7 +64,8 @@ impl Block {
             prev_block_hash,
             hash,
             pub_key,
-            signature
+            signature,
+            hash_good: RefCell::new(false)
         }
     }
 
@@ -74,6 +79,14 @@ impl Block {
             self.prev_block_hash == Bytes::default()
     }
 
+    pub fn is_hash_good(&self) -> bool {
+        *self.hash_good.borrow()
+    }
+
+    pub fn set_hash_good(&self, good: bool) {
+        *self.hash_good.borrow_mut() = good;
+    }
+
     /// Serializes block to CBOR for network
     pub fn as_bytes(&self) -> Vec<u8> {
         serde_cbor::to_vec(&self).unwrap()
diff --git a/src/blockchain/chain.rs b/src/blockchain/chain.rs
index 431f464..637548f 100644
--- a/src/blockchain/chain.rs
+++ b/src/blockchain/chain.rs
@@ -35,7 +35,7 @@ const SQL_ADD_DOMAIN: &str = "INSERT INTO domains (id, timestamp, identity, conf
 const SQL_GET_BLOCK_BY_ID: &str = "SELECT * FROM blocks WHERE id=? LIMIT 1;";
 const SQL_GET_LAST_FULL_BLOCK: &str = "SELECT * FROM blocks WHERE id < ? AND `transaction`<>'' ORDER BY id DESC LIMIT 1;";
 const SQL_GET_LAST_FULL_BLOCK_FOR_KEY: &str = "SELECT * FROM blocks WHERE id < ? AND `transaction`<>'' AND pub_key = ? ORDER BY id DESC LIMIT 1;";
-const SQL_GET_DOMAIN_OWNER_BY_ID: &str = "SELECT signing FROM domains WHERE id < ? AND identity = ? ORDER BY id DESC LIMIT 1;";
+const SQL_GET_DOMAIN_OWNER_BY_ID: &str = "SELECT signing, timestamp FROM domains WHERE id < ? AND identity = ? ORDER BY id DESC LIMIT 1;";
 const SQL_GET_DOMAIN_BY_ID: &str = "SELECT * FROM domains WHERE identity = ? AND id < ? ORDER BY id DESC LIMIT 1;";
 const SQL_GET_DOMAINS_BY_KEY: &str = "SELECT timestamp, identity, data, signing FROM domains WHERE signing = ? ORDER BY id;";
 const SQL_GET_DOMAINS_COUNT: &str = "SELECT count(DISTINCT identity) FROM domains;";
@@ -152,7 +152,7 @@ impl Chain {
                     }
 
                     //let last = self.last_block.clone().unwrap();
-                    if self.check_block(&block, &last_block, &last_full_block) != BlockQuality::Good {
+                    if self.check_block(&block, &last_block, &last_full_block) != Good {
                         error!("Block {} is bad:\n{:?}", block.index, &block);
                         info!("Truncating database from block {}...", block.index);
                         match self.truncate_db_from_block(block.index) {
@@ -391,10 +391,10 @@ impl Chain {
                 statement.bind(7, transaction.to_string().as_str())?;
             }
         }
-        statement.bind(8, &**block.prev_block_hash)?;
-        statement.bind(9, &**block.hash)?;
-        statement.bind(10, &**block.pub_key)?;
-        statement.bind(11, &**block.signature)?;
+        statement.bind(8, block.prev_block_hash.as_slice())?;
+        statement.bind(9, block.hash.as_slice())?;
+        statement.bind(10, block.pub_key.as_slice())?;
+        statement.bind(11, block.signature.as_slice())?;
         statement.next()
     }
 
@@ -409,11 +409,11 @@ impl Chain {
         let mut statement = self.db.prepare(sql)?;
         statement.bind(1, index as i64)?;
         statement.bind(2, timestamp)?;
-        statement.bind(3, &**t.identity)?;
-        statement.bind(4, &**t.confirmation)?;
+        statement.bind(3, t.identity.as_slice())?;
+        statement.bind(4, t.confirmation.as_slice())?;
         statement.bind(5, t.data.as_ref() as &str)?;
-        statement.bind(6, &**t.signing)?;
-        statement.bind(7, &**t.encryption)?;
+        statement.bind(6, t.signing.as_slice())?;
+        statement.bind(7, t.encryption.as_slice())?;
         statement.next()
     }
 
@@ -488,12 +488,13 @@ impl Chain {
     }
 
     /// Checks if any domain is available to mine for this client (pub_key)
-    pub fn is_domain_available(&self, height: u64, domain: &str, keystore: &Keystore) -> bool {
+    pub fn is_domain_available(&self, height: u64, domain: &str, public_key: &Bytes) -> bool {
         if domain.is_empty() {
             return false;
         }
         let identity_hash = hash_identity(domain, None);
-        if !self.is_id_available(height, &identity_hash, &keystore.get_public()) {
+        if !self.is_id_available(height, &identity_hash, public_key) {
+            warn!("Domain {} is not available!", domain);
             return false;
         }
 
@@ -512,7 +513,7 @@ impl Chain {
     pub fn is_id_available(&self, height: u64, identity: &Bytes, public_key: &Bytes) -> bool {
         let mut statement = self.db.prepare(SQL_GET_DOMAIN_OWNER_BY_ID).unwrap();
         statement.bind(1, height as i64).expect("Error in bind");
-        statement.bind(2, &***identity).expect("Error in bind");
+        statement.bind(2, identity.as_slice()).expect("Error in bind");
         while let State::Row = statement.next().unwrap() {
             let pub_key = Bytes::from_bytes(&statement.read::<Vec<u8>>(0).unwrap());
             if !pub_key.eq(public_key) {
@@ -557,7 +558,7 @@ impl Chain {
         // Checking for existing domain in DB
         let mut statement = self.db.prepare(SQL_GET_DOMAIN_OWNER_BY_ID).unwrap();
         statement.bind(1, height as i64).expect("Error in bind");
-        statement.bind(2, &***id).expect("Error in bind");
+        statement.bind(2, id.as_slice()).expect("Error in bind");
         if let State::Row = statement.next().unwrap() {
             // If there is such an ID
             return true;
@@ -705,7 +706,7 @@ impl Chain {
         let keystore = keystore.unwrap();
         let pub_key = keystore.get_public();
         let mut statement = self.db.prepare(SQL_GET_DOMAINS_BY_KEY).unwrap();
-        statement.bind(1, &**pub_key).expect("Error in bind");
+        statement.bind(1, pub_key.as_slice()).expect("Error in bind");
         let height = self.get_height();
         while let State::Row = statement.next().unwrap() {
             let timestamp = statement.read::<i64>(0).unwrap();
@@ -805,14 +806,10 @@ impl Chain {
         }
         if let Some(last) = last_block {
             if block.index > last.index + 1 {
-                info!("Got future block {}", block.index);
+                debug!("Got future block {}", block.index);
                 return Future;
             }
         }
-        if !check_public_key_strength(&block.pub_key, KEYSTORE_DIFFICULTY) {
-            warn!("Ignoring block with weak public key:\n{:?}", &block);
-            return Bad;
-        }
         let difficulty = match &block.transaction {
             None => {
                 if block.index == 1 {
@@ -853,12 +850,12 @@ impl Chain {
         }
 
         if let Some(transaction) = &block.transaction {
-            let current_height = match last_block {
-                None => 0,
-                Some(block) => block.index
-            };
+            if !check_public_key_strength(&block.pub_key, KEYSTORE_DIFFICULTY) {
+                warn!("Ignoring block with weak public key:\n{:?}", &block);
+                return Bad;
+            }
             // If this domain is not available to this public key
-            if !self.is_id_available(current_height, &transaction.identity, &block.pub_key) {
+            if !self.is_id_available(block.index - 1, &transaction.identity, &block.pub_key) {
                 warn!("Block {:?} is trying to spoof an identity!", &block);
                 return Bad;
             }
diff --git a/src/blockchain/hash_utils.rs b/src/blockchain/hash_utils.rs
index 24fdf62..8c73a92 100644
--- a/src/blockchain/hash_utils.rs
+++ b/src/blockchain/hash_utils.rs
@@ -7,10 +7,16 @@ use crate::{Block, Bytes, Keystore};
 
 /// Checks block's hash and returns true on valid hash or false otherwise
 pub fn check_block_hash(block: &Block) -> bool {
+    // If this block's hash was already checked as good
+    if block.is_hash_good() {
+        return true;
+    }
     let mut copy: Block = block.clone();
     copy.hash = Bytes::default();
     copy.signature = Bytes::default();
-    blakeout_data(&copy.as_bytes_compact()) == block.hash
+    let good = blakeout_data(&copy.as_bytes_compact()) == block.hash;
+    block.set_hash_good(good);
+    good
 }
 
 /// Hashes data by given hasher
diff --git a/src/p2p/network.rs b/src/p2p/network.rs
index 2b85713..578c5e5 100644
--- a/src/p2p/network.rs
+++ b/src/p2p/network.rs
@@ -598,7 +598,7 @@ impl Network {
                 if index != block.index {
                     return State::Banned;
                 }
-                info!("Received block {} with hash {:?}", block.index, &block.hash);
+                debug!("Received block {} with hash {:?}", block.index, &block.hash);
                 if !seen_blocks.contains(&block.hash) {
                     self.handle_block(token, block, seen_blocks)
                 } else {
diff --git a/src/web_ui.rs b/src/web_ui.rs
index be70844..f82fd42 100644
--- a/src/web_ui.rs
+++ b/src/web_ui.rs
@@ -126,7 +126,7 @@ fn action_check_domain(context: &Arc<Mutex<Context>>, web_view: &mut WebView<()>
     let c = context.lock().unwrap();
     if let Some(keystore) = c.get_keystore() {
         let name = name.to_lowercase();
-        let available = c.get_chain().is_domain_available(c.get_chain().get_height(), &name, keystore);
+        let available = c.get_chain().is_domain_available(c.get_chain().get_height(), &name, &keystore.get_public());
         web_view.eval(&format!("domainAvailable({})", available)).expect("Error evaluating!");
     }
 }