diff --git a/lib/rex/proto/kerberos/client.rb b/lib/rex/proto/kerberos/client.rb
index 603c5b0fac..48af233ddb 100644
--- a/lib/rex/proto/kerberos/client.rb
+++ b/lib/rex/proto/kerberos/client.rb
@@ -44,7 +44,7 @@ module Rex
           when 'tcp'
             self.connection = create_tcp_connection
           when 'udp'
-            raise ::RuntimeError, 'Kerberos Client: UDP not supported'
+            raise ::NotImplementedError, 'Kerberos Client: UDP not supported'
           else
             raise ::RuntimeError, 'Kerberos Client: unknown transport protocol'
           end
@@ -66,7 +66,8 @@ module Rex
         #
         # @param req [Rex::Proto::Kerberos::Model::KdcRequest] the request to send
         # @return [Fixnum] the number of bytes sent
-        # @raise [RuntimeError] if the transport protocol is unknown or not supported
+        # @raise [RuntimeError] if the transport protocol is unknown
+        # @raise [NotImplementedError] if the transport protocol isn't supported
         def send_request(req)
           connect
 
@@ -89,6 +90,7 @@ module Rex
         #   response message
         # @raise [RuntimeError] if the connection isn't established, the transport protocol is unknown, not supported
         #   or the response can't be parsed
+        # @raise [NotImplementedError] if the transport protocol isn't supported
         def recv_response
           if connection.nil?
             raise ::RuntimeError, 'Kerberos Client: connection not established'
@@ -111,7 +113,8 @@ module Rex
         #
         # @param req [Rex::Proto::Kerberos::Model::KdcRequest] the request to send
         # @return [<Rex::Proto::Kerberos::Model::KrbError, Rex::Proto::Kerberos::Model::KdcResponse>] The kerberos message
-        # @raise [RuntimeError] if the transport protocol is unknown, not supported, or the response can't be parsed.
+        # @raise [RuntimeError] if the transport protocol is unknown or the response can't be parsed.
+        # @raise [NotImplementedError] if the transport protocol isn't supported
         def send_recv(req)
           send_request(req)
           res = recv_response
@@ -146,9 +149,9 @@ module Rex
 
         # UDP isn't supported
         #
-        # @raise [RuntimeError]
+        # @raise [NotImplementedError]
         def send_request_udp(req)
-          raise ::RuntimeError, 'Kerberos Client: UDP unsupported'
+          raise ::NotImplementedError, 'Kerberos Client: UDP unsupported'
         end
 
         # Receives a Kerberos Response over a tcp connection
@@ -175,9 +178,9 @@ module Rex
 
         # UDP isn't supported
         #
-        # @raise [RuntimeError]
+        # @raise [NotImplementedError]
         def recv_response_udp
-          raise ::RuntimeError, 'Kerberos Client: UDP unsupported'
+          raise ::NotImplementedError, 'Kerberos Client: UDP unsupported'
         end
 
         private
diff --git a/lib/rex/proto/kerberos/credential_cache/credential.rb b/lib/rex/proto/kerberos/credential_cache/credential.rb
index dc6fcdfb77..3b9ecd8db3 100644
--- a/lib/rex/proto/kerberos/credential_cache/credential.rb
+++ b/lib/rex/proto/kerberos/credential_cache/credential.rb
@@ -101,10 +101,11 @@ module Rex
           # Encodes the addrs field
           #
           # @return [String]
+          # @raise [NotImplementedError] if there are addresses to encode
           def encode_addrs
             encoded = ''
             if addrs.length > 0
-              raise ::RuntimeError, 'CredentialCache: Credential addresses encoding not supported'
+              raise ::NotImplementedError, 'CredentialCache: Credential addresses encoding not supported'
             end
             encoded << [addrs.length].pack('N')
             encoded
diff --git a/lib/rex/proto/kerberos/model/ap_req.rb b/lib/rex/proto/kerberos/model/ap_req.rb
index 2788dcc62e..e50896d475 100644
--- a/lib/rex/proto/kerberos/model/ap_req.rb
+++ b/lib/rex/proto/kerberos/model/ap_req.rb
@@ -27,9 +27,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::ApReq decoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def decode(input)
-            raise ::RuntimeError, 'AP-REQ decoding not supported'
+            raise ::NotImplementedError, 'AP-REQ decoding not supported'
           end
 
           # Encodes the Rex::Proto::Kerberos::Model::ApReq into an ASN.1 String
diff --git a/lib/rex/proto/kerberos/model/authenticator.rb b/lib/rex/proto/kerberos/model/authenticator.rb
index 1517786f39..f849830b99 100644
--- a/lib/rex/proto/kerberos/model/authenticator.rb
+++ b/lib/rex/proto/kerberos/model/authenticator.rb
@@ -35,9 +35,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::Authenticator decoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def decode(input)
-            raise ::RuntimeError, 'Authenticator decoding not supported'
+            raise ::NotImplementedError, 'Authenticator decoding not supported'
           end
 
           # Encodes the Rex::Proto::Kerberos::Model::Authenticator into an ASN.1 String
@@ -64,6 +64,7 @@ module Rex
           # @param etype [Fixnum] the crypto schema to encrypt
           # @param key [String] the key to encrypt
           # @return [String] the encrypted result
+          # @raise [NotImplementedError] if the encryption schema isn't supported
           def encrypt(etype, key)
             data = self.encode
 
@@ -72,7 +73,7 @@ module Rex
             when RC4_HMAC
               res = encrypt_rc4_hmac(data, key, 7)
             else
-              raise ::RuntimeError, 'EncryptedData schema is not supported'
+              raise ::NotImplementedError, 'EncryptedData schema is not supported'
             end
 
             res
diff --git a/lib/rex/proto/kerberos/model/authorization_data.rb b/lib/rex/proto/kerberos/model/authorization_data.rb
index a63ff55260..ef8c74990c 100644
--- a/lib/rex/proto/kerberos/model/authorization_data.rb
+++ b/lib/rex/proto/kerberos/model/authorization_data.rb
@@ -15,9 +15,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::AuthorizationData decoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def decode(input)
-            raise ::RuntimeError, 'Authorization Data decoding not supported'
+            raise ::NotImplementedError, 'Authorization Data decoding not supported'
           end
 
           # Encodes a Rex::Proto::Kerberos::Model::AuthorizationData into an ASN.1 String
@@ -44,6 +44,7 @@ module Rex
           # @param etype [Fixnum] the crypto schema to encrypt
           # @param key [String] the key to encrypt
           # @return [String] the encrypted result
+          # @raise [NotImplementedError] if encryption schema isn't supported
           def encrypt(etype, key)
             data = self.encode
 
@@ -52,7 +53,7 @@ module Rex
             when RC4_HMAC
               res = encrypt_rc4_hmac(data, key, 5)
             else
-              raise ::RuntimeError, 'EncryptedData schema is not supported'
+              raise ::NotImplementedError, 'EncryptedData schema is not supported'
             end
 
             res
diff --git a/lib/rex/proto/kerberos/model/checksum.rb b/lib/rex/proto/kerberos/model/checksum.rb
index 6dbdeb70c4..ccd4f9c6b7 100644
--- a/lib/rex/proto/kerberos/model/checksum.rb
+++ b/lib/rex/proto/kerberos/model/checksum.rb
@@ -16,9 +16,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::Checksum decoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def decode(input)
-            raise ::RuntimeError, 'Checksum decoding not supported'
+            raise ::NotImplementedError, 'Checksum decoding not supported'
           end
 
           # Encodes a Rex::Proto::Kerberos::Model::Checksum into an ASN.1 String
diff --git a/lib/rex/proto/kerberos/model/enc_kdc_response.rb b/lib/rex/proto/kerberos/model/enc_kdc_response.rb
index b960d48b83..dd8868f68e 100644
--- a/lib/rex/proto/kerberos/model/enc_kdc_response.rb
+++ b/lib/rex/proto/kerberos/model/enc_kdc_response.rb
@@ -65,9 +65,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::EncKdcResponse encoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def encode
-            raise ::RuntimeError, 'EncKdcResponse encoding not supported'
+            raise ::NotImplementedError, 'EncKdcResponse encoding not supported'
           end
 
           private
diff --git a/lib/rex/proto/kerberos/model/encrypted_data.rb b/lib/rex/proto/kerberos/model/encrypted_data.rb
index 9fb8a4f754..17425adb35 100644
--- a/lib/rex/proto/kerberos/model/encrypted_data.rb
+++ b/lib/rex/proto/kerberos/model/encrypted_data.rb
@@ -61,6 +61,7 @@ module Rex
           # @param msg_type [Fixnum] the message type
           # @return [String] the decrypted `cipher`
           # @raise [RuntimeError] if decryption doesn't succeed
+          # @raise [NotImplementedError] if encryption isn't supported
           def decrypt(key, msg_type)
             if cipher.nil? || cipher.empty?
               return ''
@@ -73,7 +74,7 @@ module Rex
               raise ::RuntimeError, 'EncryptedData failed to decrypt' if res.length < 8
               res = res[8, res.length - 1]
             else
-              raise ::RuntimeError, 'EncryptedData schema is not supported'
+              raise ::NotImplementedError, 'EncryptedData schema is not supported'
             end
 
             res
diff --git a/lib/rex/proto/kerberos/model/kdc_request_body.rb b/lib/rex/proto/kerberos/model/kdc_request_body.rb
index fce0b59328..d9f2baacf7 100644
--- a/lib/rex/proto/kerberos/model/kdc_request_body.rb
+++ b/lib/rex/proto/kerberos/model/kdc_request_body.rb
@@ -82,6 +82,7 @@ module Rex
           #
           # @param etype [Fixnum] the crypto schema to checksum
           # @return [String] the checksum
+          # @raise [NotImplementedError] if the encryption schema isn't supported
           def checksum(etype)
             data = self.encode
 
@@ -90,7 +91,7 @@ module Rex
             when RSA_MD5
               res = checksum_rsa_md5(data)
             else
-              raise ::RuntimeError, 'EncryptedData schema is not supported'
+              raise ::NotImplementedError, 'EncryptedData schema is not supported'
             end
 
             res
diff --git a/lib/rex/proto/kerberos/model/kdc_response.rb b/lib/rex/proto/kerberos/model/kdc_response.rb
index 8d43a9e123..02c119d5b7 100644
--- a/lib/rex/proto/kerberos/model/kdc_response.rb
+++ b/lib/rex/proto/kerberos/model/kdc_response.rb
@@ -46,9 +46,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::KdcResponse encoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def encode
-            raise ::RuntimeError, 'KdcResponse encoding not supported'
+            raise ::NotImplementedError, 'KdcResponse encoding not supported'
           end
 
           private
diff --git a/lib/rex/proto/kerberos/model/krb_error.rb b/lib/rex/proto/kerberos/model/krb_error.rb
index d4a58a55dc..e20772e86d 100644
--- a/lib/rex/proto/kerberos/model/krb_error.rb
+++ b/lib/rex/proto/kerberos/model/krb_error.rb
@@ -64,9 +64,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::KrbError encoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def encode
-            raise ::RuntimeError, 'KrbError encoding not supported'
+            raise ::NotImplementedError, 'KrbError encoding not supported'
           end
 
           private
diff --git a/lib/rex/proto/kerberos/model/last_request.rb b/lib/rex/proto/kerberos/model/last_request.rb
index adcd01c2f9..cd9bdd4837 100644
--- a/lib/rex/proto/kerberos/model/last_request.rb
+++ b/lib/rex/proto/kerberos/model/last_request.rb
@@ -34,9 +34,9 @@ module Rex
 
           # Rex::Proto::Kerberos::Model::LastRequest encoding isn't supported
           #
-          # @raise [RuntimeError]
+          # @raise [NotImplementedError]
           def encode
-            raise ::RuntimeError, 'LastRequest encoding not supported'
+            raise ::NotImplementedError, 'LastRequest encoding not supported'
           end
 
           private
diff --git a/lib/rex/proto/kerberos/model/pre_auth_enc_time_stamp.rb b/lib/rex/proto/kerberos/model/pre_auth_enc_time_stamp.rb
index 62c24c0ccd..76415db244 100644
--- a/lib/rex/proto/kerberos/model/pre_auth_enc_time_stamp.rb
+++ b/lib/rex/proto/kerberos/model/pre_auth_enc_time_stamp.rb
@@ -52,6 +52,7 @@ module Rex
           # @param etype [Fixnum] the crypto schema to encrypt
           # @param key [String] the key to encrypt
           # @return [String] the encrypted result
+          # @raise [NotImplementedError] if encryption schema isn't supported
           def encrypt(etype, key)
             data = self.encode
 
@@ -60,7 +61,7 @@ module Rex
             when RC4_HMAC
               res = encrypt_rc4_hmac(data, key, CRYPTO_MSG_TYPE)
             else
-              raise ::RuntimeError, 'EncryptedData schema is not supported'
+              raise ::NotImplementedError, 'EncryptedData schema is not supported'
             end
 
             res
diff --git a/lib/rex/proto/kerberos/pac/type.rb b/lib/rex/proto/kerberos/pac/type.rb
index 7643ad8115..980461ea02 100644
--- a/lib/rex/proto/kerberos/pac/type.rb
+++ b/lib/rex/proto/kerberos/pac/type.rb
@@ -102,13 +102,14 @@ module Rex
           #
           # @param data [String] the data to checksum
           # @return [String] the checksum result
+          # @raise [NotImplementedError] if checksum schema isn't supported
           def make_checksum(data)
             res = ''
             case checksum
             when RSA_MD5
               res = checksum_rsa_md5(data)
             else
-              raise ::RuntimeError, 'PAC-TYPE checksum not supported'
+              raise ::NotImplementedError, 'PAC-TYPE checksum not supported'
             end
 
             res