diff --git a/src/Constants.js b/src/Constants.js
index 1220bdd43..74948b37f 100644
--- a/src/Constants.js
+++ b/src/Constants.js
@@ -62,8 +62,10 @@ CONSTANTS = {
     ScriptHNUpgRamRamCost:          0.6,
     ScriptHNUpgCoreRamCost:         0.8,
     
-    //Server growth rate
-    ServerGrowthRate: 1.0018,
+    //Server constants
+    ServerGrowthRate: 1.0018,   //Growth rate
+    ServerFortifyAmount: 0.001, //Amount by which server's security increases when its hacked
+    ServerWeakenAmount: 0.1,    //Amount by which server's security decreases when weakened
     
     //Maximum number of log entries for a script
     MaxLogCapacity: 40,
diff --git a/src/NetscriptEvaluator.js b/src/NetscriptEvaluator.js
index a26353e96..c3d851455 100644
--- a/src/NetscriptEvaluator.js
+++ b/src/NetscriptEvaluator.js
@@ -288,6 +288,7 @@ function evaluate(exp, workerScript) {
 										workerScript.scriptRef.onlineExpGained += expGainedOnSuccess;
 										console.log("Script successfully hacked " + server.hostname + " for $" + formatNumber(moneyGained, 2) + " and " + formatNumber(expGainedOnSuccess, 4) +  " exp");
                                         workerScript.scriptRef.log("Script SUCCESSFULLY hacked " + server.hostname + " for $" + formatNumber(moneyGained, 2) + " and " + formatNumber(expGainedOnSuccess, 4) +  " exp");
+                                        server.fortify(CONSTANTS.ServerFortifyAmount);
 										resolve("Hack success");
 									} else {	
                                         if (env.stopFlag) {reject(workerScript); return;}
diff --git a/src/Server.js b/src/Server.js
index aff18b744..e5ada5f7d 100644
--- a/src/Server.js
+++ b/src/Server.js
@@ -108,6 +108,17 @@ Server.prototype.getScript = function(scriptName) {
 	return null; 
 }
 
+//Strengthens a server's security level (difficulty) by the specified amount
+Server.prototype.fortify = function(amt) {
+    this.hackDifficulty += amt; 
+    if (this.hackDifficulty > 99) {this.hackDifficulty = 99;}
+}
+
+Server.prototype.weaken = function(amt) {
+    this.hackDifficulty -= amt; 
+    if (this.hackDifficulty < 1) {this.hackDifficulty = 1;}
+}
+
 //Functions for loading and saving a Server
 Server.prototype.toJSON = function() {
 	return Generic_toJSON("Server", this);
diff --git a/src/Terminal.js b/src/Terminal.js
index b96a39363..6d9d92889 100644
--- a/src/Terminal.js
+++ b/src/Terminal.js
@@ -291,6 +291,8 @@ var Terminal = {
 				Player.gainMoney(moneyGained);
 				
                 Player.gainHackingExp(expGainedOnSuccess)
+                
+                Player.getCurrentServer().fortify(CONSTANTS.ServerFortifyAmount);
 				
 				post("Hack successful! Gained $" + formatNumber(moneyGained, 2) + " and " + formatNumber(expGainedOnSuccess, 4) + " hacking EXP");
 			} else {					//Failure
@@ -317,8 +319,7 @@ var Terminal = {
             else {rootAccess = "NO";}
             post("Root Access: " + rootAccess);
 			post("Required hacking skill: " + Player.getCurrentServer().requiredHackingSkill);
-			//TODO Make these actual estimates by adding a random offset to result?
-			//TODO Change the text to sound better
+			post("Estimated server security level(1-100): " + formatNumber(addOffset(Player.getCurrentServer().hackDifficulty, 5), 0));
 			post("Estimated chance to hack: " + formatNumber(addOffset(Player.calculateHackingChance() * 100, 5), 2) + "%");
 			post("Estimated time to hack: " + formatNumber(addOffset(Player.calculateHackingTime(), 5), 3) + " seconds");
 			post("Estimated total money available on server: $" + formatNumber(addOffset(Player.getCurrentServer().moneyAvailable, 5), 2));