diff --git a/doc/ins_sign_stake_pool_registration.md b/doc/ins_sign_stake_pool_registration.md
index 70106a6e..f8ee324c 100644
--- a/doc/ins_sign_stake_pool_registration.md
+++ b/doc/ins_sign_stake_pool_registration.md
@@ -157,12 +157,12 @@ P2 = `0x36`
 |relay format       |  1 | `RELAY_SINGLE_HOST_NAME=0x01` |
 |isPortGiven        |  1 | `ITEM_INCLUDED_NO=0x01` or `ITEM_INCLUDED_YES=0x02` |
 |port               |  2 | Big endian; included if and only if isPortGiven is `ITEM_INCLUDED_YES`
-|dns name           | variable | byte buffer, max size 64
+|dns name           | variable | byte buffer, max size 128
 
 |Field| Length | Comments|
 |-----|--------|---------|
 |relay format       |  1 | `RELAY_MULTIPLE_HOST_NAME=0x02` |
-|dns name           | variable | byte buffer, max size 64
+|dns name           | variable | byte buffer, max size 128
 
 
 ---
@@ -175,7 +175,7 @@ P2 = `0x37`
 |-----|--------|---------|
 |includeMetadata    |  1 | `ITEM_INCLUDED_NO=0x01` or `ITEM_INCLUDED_YES=0x02` |
 |metadata hash      | 32 | byte buffer; only if includeMetadata is `ITEM_INCLUDED_YES`
-|metadata url       | variable | byte buffer, max size 64; only if includeMetadata is `ITEM_INCLUDED_YES`
+|metadata url       | variable | byte buffer, max size 128; only if includeMetadata is `ITEM_INCLUDED_YES`
 
 
 ---
diff --git a/src/cardano.h b/src/cardano.h
index 95249ac1..cc99ac2c 100644
--- a/src/cardano.h
+++ b/src/cardano.h
@@ -101,10 +101,10 @@ typedef struct {
 
 // ==============================  CERTIFICATES  ==============================
 
-#define ANCHOR_URL_LENGTH_MAX 64
+#define ANCHOR_URL_LENGTH_MAX 128
 
-#define POOL_METADATA_URL_LENGTH_MAX 64
-#define DNS_NAME_SIZE_MAX 64
+#define POOL_METADATA_URL_LENGTH_MAX 128
+#define DNS_NAME_SIZE_MAX 128
 
 #define IPV4_SIZE 4
 #define IPV6_SIZE 16