diff --git a/src/ERC6538Registry.sol b/src/ERC6538Registry.sol
index 925ab9c..c6b4df4 100644
--- a/src/ERC6538Registry.sol
+++ b/src/ERC6538Registry.sol
@@ -14,10 +14,6 @@ contract ERC6538Registry {
   /// @dev `nonce` will be incremented after each valid `registerKeysOnBehalf` call.
   mapping(address user => uint256) public nonceOf;
 
-  /// @dev EIP-712 Type hash used in `registerKeysOnBehalf`.
-  bytes32 public constant TYPE_HASH =
-    keccak256("EIP712Domain(string name,string version,uint256 chainId,address registryContract)");
-
   /// @dev The chain ID where this contract is initially deployed.
   uint256 internal immutable INITIAL_CHAIN_ID;
 
@@ -76,7 +72,15 @@ contract ERC6538Registry {
           "\x19\x01",
           DOMAIN_SEPARATOR(),
           keccak256(
-            abi.encode(TYPE_HASH, registrant, schemeId, stealthMetaAddress, nonceOf[registrant]++)
+            abi.encode(
+              keccak256(
+                "RegisterKeysOnBehalf(address registrant,uint256 schemeId,bytes stealthMetaAddress,uint256 nonce)"
+              ),
+              registrant,
+              schemeId,
+              stealthMetaAddress,
+              nonceOf[registrant]++
+            )
           )
         )
       );
@@ -126,7 +130,13 @@ contract ERC6538Registry {
   function _computeDomainSeparator() internal view returns (bytes32) {
     return keccak256(
       abi.encode(
-        TYPE_HASH, keccak256("ERC6538Registry"), keccak256("1.0"), block.chainid, address(this)
+        keccak256(
+          "EIP712Domain(string name,string version,uint256 chainId,address registryContract)"
+        ),
+        keccak256("ERC6538Registry"),
+        keccak256("1.0"),
+        block.chainid,
+        address(this)
       )
     );
   }
diff --git a/test/ERC6538Registry.t.sol b/test/ERC6538Registry.t.sol
index 4165280..9906678 100644
--- a/test/ERC6538Registry.t.sol
+++ b/test/ERC6538Registry.t.sol
@@ -299,9 +299,6 @@ contract SigUtils {
     DOMAIN_SEPARATOR = _DOMAIN_SEPARATOR;
   }
 
-  bytes32 public constant TYPEHASH =
-    keccak256("EIP712Domain(string name,string version,uint256 chainId,address registryContract)");
-
   struct RegistrantInfo {
     address registrant;
     uint256 schemeId;
@@ -312,7 +309,15 @@ contract SigUtils {
   // computes the hash
   function getStructHash(RegistrantInfo memory _info) internal pure returns (bytes32) {
     return keccak256(
-      abi.encode(TYPEHASH, _info.registrant, _info.schemeId, _info.stealthMetaAddress, _info.nonce)
+      abi.encode(
+        keccak256(
+          "RegisterKeysOnBehalf(address registrant,uint256 schemeId,bytes stealthMetaAddress,uint256 nonce)"
+        ),
+        _info.registrant,
+        _info.schemeId,
+        _info.stealthMetaAddress,
+        _info.nonce
+      )
     );
   }