diff --git a/README.md b/README.md
index 7a23795..a0e634b 100644
--- a/README.md
+++ b/README.md
@@ -161,6 +161,7 @@ owasp.config({
   minLength              : 10,
   minPhraseLength        : 20,
   minOptionalTestsToPass : 4,
+  i18nErrorKeys          : false,
 });
 ```
 
@@ -184,6 +185,12 @@ Whereby:
   OWASP guidelines), four optional complexity tests are made, and a password
   must pass at least three of them in order to be considered "strong". 
 
+- `i18nErrorKeys` is a `boolean` that toggles the i18n error keys in place of
+  english error messages. This can be useful when translating the errors using
+  a 3rd party i18n library. When true the following keys can be returned:
+  `failedMinLength`, `failedMaxLength`, `failedThreeRepeatedChars`,
+  `optionalLowercaseRequired`, `optionalUppercaseRequired`,
+  `optionalNumberRequired` and `optionalSpecialCharRequired`.
 
 Extending
 ---------
diff --git a/owasp-password-strength-test.js b/owasp-password-strength-test.js
index 1179b6d..e2b1bb4 100644
--- a/owasp-password-strength-test.js
+++ b/owasp-password-strength-test.js
@@ -21,6 +21,7 @@
       minLength              : 10,
       minPhraseLength        : 20,
       minOptionalTestsToPass : 4,
+      i18nErrorKeys          : false,
     };
 
     // This method makes it more convenient to set config parameters
@@ -42,21 +43,27 @@
         // enforce a minimum length
         function(password) {
           if (password.length < owasp.configs.minLength) {
-            return 'The password must be at least ' + owasp.configs.minLength + ' characters long.';
+            return owasp.configs.i18nErrorKeys
+              ? 'failedMinLength'
+              : 'The password must be at least ' + owasp.configs.minLength + ' characters long.';
           }
         },
 
         // enforce a maximum length
         function(password) {
           if (password.length > owasp.configs.maxLength) {
-            return 'The password must be fewer than ' + owasp.configs.maxLength + ' characters.';
+            return owasp.configs.i18nErrorKeys
+              ? 'failedMaxLength'
+              : 'The password must be fewer than ' + owasp.configs.maxLength + ' characters.';
           }
         },
 
         // forbid repeating characters
         function(password) {
           if (/(.)\1{2,}/.test(password)) {
-            return 'The password may not contain sequences of three or more repeated characters.';
+            return owasp.configs.i18nErrorKeys
+              ? 'failedThreeRepeatedChars'
+              : 'The password may not contain sequences of three or more repeated characters.';
           }
         },
 
@@ -76,28 +83,36 @@
         // require at least one lowercase letter
         function(password) {
           if (!/[a-z]/.test(password)) {
-            return 'The password must contain at least one lowercase letter.';
+            return owasp.configs.i18nErrorKeys
+              ? 'optionalLowercaseRequired'
+              : 'The password must contain at least one lowercase letter.';
           }
         },
 
         // require at least one uppercase letter
         function(password) {
           if (!/[A-Z]/.test(password)) {
-            return 'The password must contain at least one uppercase letter.';
+            return owasp.configs.i18nErrorKeys
+              ? 'optionalUppercaseRequired'
+              : 'The password must contain at least one uppercase letter.';
           }
         },
 
         // require at least one number
         function(password) {
           if (!/[0-9]/.test(password)) {
-            return 'The password must contain at least one number.';
+            return owasp.configs.i18nErrorKeys
+              ? 'optionalNumberRequired'
+              : 'The password must contain at least one number.';
           }
         },
 
         // require at least one special character
         function(password) {
           if (!/[^A-Za-z0-9]/.test(password)) {
-            return 'The password must contain at least one special character.';
+            return owasp.configs.i18nErrorKeys
+              ? 'optionalSpecialCharRequired'
+              : 'The password must contain at least one special character.';
           }
         },
 
diff --git a/test.js b/test.js
index 66659c9..1668aeb 100644
--- a/test.js
+++ b/test.js
@@ -124,12 +124,14 @@ describe('configs', function() {
       minLength              : 5,
       minPhraseLength        : 5,
       minOptionalTestsToPass : 5,
+      i18nErrorKeys          : true,
     });
     owasp.configs.allowPassphrases.should.be.false;
     owasp.configs.maxLength.should.be.exactly(5);
     owasp.configs.minLength.should.be.exactly(5);
     owasp.configs.minPhraseLength.should.be.exactly(5);
     owasp.configs.minOptionalTestsToPass.should.be.exactly(5);
+    owasp.configs.i18nErrorKeys.should.be.true;
   });
 
   it('should reject invalid parameter keys', function() {
@@ -138,3 +140,24 @@ describe('configs', function() {
   });
 
 });
+
+describe('i18n', function() {
+
+  it('should return i18 error keys', function() {
+    owasp.config({
+      allowPassphrases       : true,
+      maxLength              : 50,
+      minLength              : 10,
+      minPhraseLength        : 20,
+      minOptionalTestsToPass : 3,
+      i18nErrorKeys          : true,
+    });
+    var result = owasp.test('L0eSex');
+    result.errors.should.have.length(2);
+    result.requiredTestErrors.should.have.length(1);
+    result.requiredTestErrors[0].should.be.exactly('failedMinLength');
+    owasp.configs.minLength.should.be.exactly(10);
+    result.optionalTestErrors[0].should.be.exactly('optionalSpecialCharRequired');
+  });
+
+});