diff --git a/cmd_deploy_itns.go b/cmd_deploy_itns.go
index e3199c3..1bf837e 100644
--- a/cmd_deploy_itns.go
+++ b/cmd_deploy_itns.go
@@ -62,7 +62,7 @@ func runDeployITNS(walletRPC string) error {
 	desc := rpc.AssetDescriptor{
 		Ticker:       "ITNS",
 		FullName:     "IntenseCoin",
-		TotalMax:     1000000000000000000, // 1B at 12 decimals
+		TotalMax:     AtomicUnit * 1000000, // 1B at 12 decimals
 		CurrentSup:   0,
 		DecimalPoint: 12,
 		HiddenSupply: false,
diff --git a/cmd_wallet.go b/cmd_wallet.go
index 8e2b28c..eb0b4c8 100644
--- a/cmd_wallet.go
+++ b/cmd_wallet.go
@@ -104,7 +104,7 @@ func runWalletCreate(walletFile string) error {
 	}
 
 	addr := account.Address()
-	addrStr := addr.Encode(0x1eaf7) // iTHN standard prefix
+	addrStr := addr.Encode(StandardPrefix) // iTHN standard prefix
 	seed, _ := account.ToSeed()
 
 	core.Print(nil, "Wallet created!")
@@ -132,7 +132,7 @@ func runWalletAddress(walletFile string) error {
 	}
 
 	addr := account.Address()
-	core.Print(nil, "%s", addr.Encode(0x1eaf7))
+	core.Print(nil, "%s", addr.Encode(StandardPrefix))
 	return nil
 }
 
@@ -193,7 +193,7 @@ func runWalletScan(walletFile, daemonURL string) error {
 	}
 
 	addr := account.Address()
-	core.Print(nil, "Scanning for: %s", addr.Encode(0x1eaf7))
+	core.Print(nil, "Scanning for: %s", addr.Encode(StandardPrefix))
 
 	scanner := wallet.NewV1Scanner(account)
 	client := rpc.NewClient(daemonURL)
@@ -244,7 +244,7 @@ func runWalletScan(walletFile, daemonURL string) error {
 					totalBalance += t.Amount
 					outputCount++
 					core.Print(nil, "  Found output: %d.%012d LTHN at height %d",
-						t.Amount/1000000000000, t.Amount%1000000000000, h)
+						t.Amount/AtomicUnit, t.Amount%AtomicUnit, h)
 				}
 			}
 		}
@@ -252,12 +252,12 @@ func runWalletScan(walletFile, daemonURL string) error {
 		if h > 0 && h%1000 == 0 {
 			core.Print(nil, "  Scanned %d/%d blocks... (%d outputs, %d.%012d LTHN)",
 				h, remoteHeight, outputCount,
-				totalBalance/1000000000000, totalBalance%1000000000000)
+				totalBalance/AtomicUnit, totalBalance%AtomicUnit)
 		}
 	}
 
 	core.Print(nil, "Balance: %d.%012d LTHN (%d outputs)",
-		totalBalance/1000000000000, totalBalance%1000000000000, outputCount)
+		totalBalance/AtomicUnit, totalBalance%AtomicUnit, outputCount)
 
 	return nil
 }
@@ -335,7 +335,7 @@ func runWalletRestore(walletFile, seed string) error {
 
 	addr := account.Address()
 	core.Print(nil, "Wallet restored!")
-	core.Print(nil, "  Address: %s", addr.Encode(0x1eaf7))
+	core.Print(nil, "  Address: %s", addr.Encode(StandardPrefix))
 	core.Print(nil, "  File:    %s", walletFile)
 
 	return nil
@@ -372,7 +372,7 @@ func runWalletTransfer(walletRPC, destination string, amount float64, paymentID
 		return coreerr.E("runWalletTransfer", "destination must start with iTHN", nil)
 	}
 
-	atomicAmount := uint64(amount * 1000000000000) // 12 decimal places
+	atomicAmount := uint64(amount * AtomicUnit) // 12 decimal places
 
 	core.Print(nil, "Sending %f LTHN to %s...", amount, destination[:20]+"...")
 
@@ -464,9 +464,9 @@ func runWalletInfo(walletFile string) error {
 
 	core.Print(nil, "Wallet Information")
 	core.Print(nil, "  File:      %s", walletFile)
-	core.Print(nil, "  Address:   %s", addr.Encode(0x1eaf7))
-	core.Print(nil, "  Integrated: %s", addr.Encode(0xdeaf7))
-	core.Print(nil, "  Auditable: %s", addr.Encode(0x3ceff7))
+	core.Print(nil, "  Address:   %s", addr.Encode(StandardPrefix))
+	core.Print(nil, "  Integrated: %s", addr.Encode(IntegratedPrefix))
+	core.Print(nil, "  Auditable: %s", addr.Encode(AuditablePrefix))
 	core.Print(nil, "  Spend Key: %x", account.SpendPublicKey[:])
 	core.Print(nil, "  View Key:  %x", account.ViewPublicKey[:])
 	core.Print(nil, "  Seed:      %s", seed)
diff --git a/constants.go b/constants.go
new file mode 100644
index 0000000..e92b824
--- /dev/null
+++ b/constants.go
@@ -0,0 +1,52 @@
+// Copyright (c) 2017-2026 Lethean (https://lt.hn)
+// SPDX-License-Identifier: EUPL-1.2
+
+package blockchain
+
+// Chain constants used across commands and services.
+const (
+	// AtomicUnit is the number of atomic units per 1 LTHN.
+	AtomicUnit uint64 = 1000000000000
+
+	// StandardPrefix is the base58 address prefix for standard addresses.
+	StandardPrefix uint64 = 0x1eaf7
+
+	// IntegratedPrefix is the base58 prefix for integrated addresses.
+	IntegratedPrefix uint64 = 0xdeaf7
+
+	// AuditablePrefix is the base58 prefix for auditable addresses.
+	AuditablePrefix uint64 = 0x3ceff7
+
+	// AuditableIntegratedPrefix is the base58 prefix for auditable integrated.
+	AuditableIntegratedPrefix uint64 = 0x8b077
+
+	// HF5Height is the activation height for confidential assets.
+	HF5Height uint64 = 11500
+
+	// HF4Height is the activation height for Zarcanum.
+	HF4Height uint64 = 11000
+
+	// DefaultBlockReward is the fixed block reward in LTHN.
+	DefaultBlockReward uint64 = 1
+
+	// DefaultFee is the default transaction fee in atomic units.
+	DefaultFee uint64 = 10000000000 // 0.01 LTHN
+
+	// PremineAmount is the genesis premine in LTHN.
+	PremineAmount uint64 = 10000000
+
+	// TestnetDaemonRPC is the default testnet daemon RPC port.
+	TestnetDaemonRPC = "46941"
+
+	// TestnetWalletRPC is the default testnet wallet RPC port.
+	TestnetWalletRPC = "46944"
+
+	// TestnetP2P is the default testnet P2P port.
+	TestnetP2P = "46942"
+
+	// MainnetDaemonRPC is the default mainnet daemon RPC port.
+	MainnetDaemonRPC = "36941"
+
+	// TestnetHSDPort is the default HSD sidechain RPC port.
+	TestnetHSDPort = "14037"
+)
diff --git a/service.go b/service.go
index b8b38a2..8df937a 100644
--- a/service.go
+++ b/service.go
@@ -66,7 +66,7 @@ func NewBlockchainService(c *core.Core, opts BlockchainOptions) *BlockchainServi
 
 func (s *BlockchainService) start() core.Result {
 	if s.opts.Testnet {
-		chain.GenesisHash = "7cf844dc3e7d8dd6af65642c68164ebe18109aa5167b5f76043f310dd6e142d0"
+		chain.GenesisHash = chain.TestnetGenesisHash
 	}
 
 	dbPath := core.JoinPath(s.opts.DataDir, "chain.db")