diff --git a/src/blockchain_block_v1.proto b/src/blockchain_block_v1.proto
index 487fae54..b2ebdc83 100644
--- a/src/blockchain_block_v1.proto
+++ b/src/blockchain_block_v1.proto
@@ -13,7 +13,7 @@ message blockchain_seen_vote_v1 {
 }
 
 message blockchain_poc_key {
-  uint32 pos = 1;
+  bytes address = 1;
   bytes key = 2;
 }