diff --git a/server/app/com/xsn/explorer/data/anorm/dao/BlockPostgresDAO.scala b/server/app/com/xsn/explorer/data/anorm/dao/BlockPostgresDAO.scala
index 5b47b4f..1cadc7c 100644
--- a/server/app/com/xsn/explorer/data/anorm/dao/BlockPostgresDAO.scala
+++ b/server/app/com/xsn/explorer/data/anorm/dao/BlockPostgresDAO.scala
@@ -14,15 +14,15 @@ class BlockPostgresDAO {
       """
         |INSERT INTO blocks
         |  (
-        |    hash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
+        |    blockhash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
         |    height, version, time, median_time, nonce, bits, chainwork, difficulty
         |  )
         |VALUES
         |  (
-        |    {hash}, {previous_blockhash}, {next_blockhash}, {tpos_contract}, {merkle_root}, {size},
+        |    {blockhash}, {previous_blockhash}, {next_blockhash}, {tpos_contract}, {merkle_root}, {size},
         |    {height}, {version}, {time}, {median_time}, {nonce}, {bits}, {chainwork}, {difficulty}
         |  )
-        |ON CONFLICT (hash)
+        |ON CONFLICT (blockhash)
         |DO UPDATE
         |  SET previous_blockhash = EXCLUDED.previous_blockhash,
         |      next_blockhash = EXCLUDED.next_blockhash,
@@ -37,11 +37,11 @@ class BlockPostgresDAO {
         |      bits = EXCLUDED.bits,
         |      chainwork = EXCLUDED.chainwork,
         |      difficulty = EXCLUDED.difficulty
-        |RETURNING hash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
+        |RETURNING blockhash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
         |          height, version, time, median_time, nonce, bits, chainwork, difficulty
       """.stripMargin
     ).on(
-      'hash -> block.hash.string,
+      'blockhash -> block.hash.string,
       'previous_blockhash -> block.previousBlockhash.map(_.string),
       'next_blockhash -> block.nextBlockhash.map(_.string),
       'tpos_contract -> block.tposContract.map(_.string),
@@ -61,13 +61,13 @@ class BlockPostgresDAO {
   def getBy(blockhash: Blockhash)(implicit conn: Connection): Option[Block] = {
     SQL(
       """
-        |SELECT hash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
+        |SELECT blockhash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
         |       height, version, time, median_time, nonce, bits, chainwork, difficulty
         |FROM blocks
-        |WHERE hash = {hash}
+        |WHERE blockhash = {blockhash}
       """.stripMargin
     ).on(
-      "hash" -> blockhash.string
+      "blockhash" -> blockhash.string
     ).as(parseBlock.singleOpt).flatten
   }
 
@@ -75,19 +75,19 @@ class BlockPostgresDAO {
     SQL(
       """
         |DELETE FROM blocks
-        |WHERE hash = {hash}
-        |RETURNING hash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
+        |WHERE blockhash = {blockhash}
+        |RETURNING blockhash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
         |          height, version, time, median_time, nonce, bits, chainwork, difficulty
       """.stripMargin
     ).on(
-      "hash" -> blockhash.string
+      "blockhash" -> blockhash.string
     ).as(parseBlock.singleOpt).flatten
   }
 
   def getLatestBlock(implicit conn: Connection): Option[Block] = {
     SQL(
       """
-        |SELECT hash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
+        |SELECT blockhash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
         |       height, version, time, median_time, nonce, bits, chainwork, difficulty
         |FROM blocks
         |ORDER BY height DESC
@@ -99,7 +99,7 @@ class BlockPostgresDAO {
   def getFirstBlock(implicit conn: Connection): Option[Block] = {
     SQL(
       """
-        |SELECT hash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
+        |SELECT blockhash, previous_blockhash, next_blockhash, tpos_contract, merkle_root, size,
         |       height, version, time, median_time, nonce, bits, chainwork, difficulty
         |FROM blocks
         |ORDER BY height
diff --git a/server/app/com/xsn/explorer/data/anorm/parsers/BlockParsers.scala b/server/app/com/xsn/explorer/data/anorm/parsers/BlockParsers.scala
index a10aa55..93403dd 100644
--- a/server/app/com/xsn/explorer/data/anorm/parsers/BlockParsers.scala
+++ b/server/app/com/xsn/explorer/data/anorm/parsers/BlockParsers.scala
@@ -9,7 +9,6 @@ object BlockParsers {
 
   import CommonParsers._
 
-  val parseHash = str("hash").map(Blockhash.from)
   val parseNextBlockhash = str("next_blockhash").map(Blockhash.from)
   val parsePreviousBlockhash = str("previous_blockhash").map(Blockhash.from)
   val parseTposContract = str("tpos_contract").map(TransactionId.from)
@@ -24,7 +23,7 @@ object BlockParsers {
   val parseDifficulty = get[BigDecimal]("difficulty")
 
   val parseBlock = (
-      parseHash ~
+      parseBlockhash ~
           parseNextBlockhash.? ~
           parsePreviousBlockhash.? ~
           parseTposContract.? ~
diff --git a/server/conf/evolutions/default/1.sql b/server/conf/evolutions/default/1.sql
index 2b5cf85..5f77220 100644
--- a/server/conf/evolutions/default/1.sql
+++ b/server/conf/evolutions/default/1.sql
@@ -2,7 +2,7 @@
 # --- !Ups
 
 CREATE TABLE blocks(
-  hash VARCHAR(64) NOT NULL,
+  blockhash VARCHAR(64) NOT NULL,
   previous_blockhash VARCHAR(64) NULL,
   next_blockhash VARCHAR(64) NULL,
   merkle_root VARCHAR(64) NULL,
@@ -17,7 +17,11 @@ CREATE TABLE blocks(
   chainwork VARCHAR(80) NOT NULL,
   difficulty DECIMAL(30, 20),
   -- constraints
-  CONSTRAINT blocks_hash_pk PRIMARY KEY (hash)
+  CONSTRAINT blocks_blockhash_pk PRIMARY KEY (blockhash),
+  CONSTRAINT blocks_blockhash_format CHECK (blockhash ~ '^[a-f0-9]{64}$'),
+  CONSTRAINT blocks_previous_blockhash_format CHECK (previous_blockhash ~ '^[a-f0-9]{64}$'),
+  CONSTRAINT blocks_next_blockhash_format CHECK (next_blockhash ~ '^[a-f0-9]{64}$'),
+  CONSTRAINT blocks_tpos_contract_format CHECK (tpos_contract ~ '^[a-f0-9]{64}$')
 );
 
 CREATE INDEX blocks_height_index ON blocks USING BTREE (height);