add specs for empty message

README.md

@@ -51,6 +51,12 @@ You can create a keypair which returns the public and private keys. The private
 
 Using the keypair you can sign a message and then verify it
 
+## Developement
+
+You must generate the encryption.o before the library is usable and before the specs will run.
+
+`cd encryption && make`
+
 ## Contributing
 
 1. Fork it (<https://github.com/sushichain/crystal-ecdsa/fork>)

spec/crystal-ecdsa_spec.cr

@@ -84,12 +84,12 @@ describe ECCrypto do
       end
     end
 
-    # it "should raise an error on empty message" do
-    #   expect_raises(Exception, "Message must not be empty") do
-    #     receiver_public_key = ECCrypto.create_key_pair[:hex_public_key]
-    #     ECCrypto.encrypt(receiver_public_key, "")
-    #   end
-    # end
+    it "should raise an error on empty message" do
+      expect_raises(Exception, "Message must not be empty") do
+        receiver_public_key = ECCrypto.create_key_pair[:hex_public_key]
+        ECCrypto.encrypt(receiver_public_key, "")
+      end
+    end
   end
 
   describe "Decrypt errors" do
@@ -115,13 +115,13 @@ describe ECCrypto do
       end
     end
 
-    # it "should raise an error on empty decrypt message" do
-    #   receiver_private_key = ECCrypto.create_key_pair[:hex_private_key]
-    #
-    #   expect_raises(Exception, "Message must not be empty") do
-    #      ECCrypto.decrypt(receiver_private_key, "")
-    #   end
-    # end
+    it "should raise an error on empty decrypt message" do
+      receiver_private_key = ECCrypto.create_key_pair[:hex_private_key]
+
+      expect_raises(Exception, "Encrypted message must not be empty") do
+         ECCrypto.decrypt(receiver_private_key, "")
+      end
+    end
 
     it "should raise an error when encrypted message was not encrypted by this library" do
       receiver_key_pair = ECCrypto.create_key_pair

src/crystal-ecdsa.cr

@@ -211,6 +211,7 @@ module ECCrypto
     # set the group type from NID
     eccgrp_id = LibECCrypto.OBJ_txt2nid("secp256k1")
     raise "Error could not set EC group" unless eccgrp_id != 0
+    raise "Message must not be empty" unless message.size > 0
 
     # use the crypto library to encrypt the message using the receiver public key and get the ephemeral public key, the init vector and the tag
     #    (we add one to message size to encrypt the null at the end of the string)
@@ -229,8 +230,9 @@ module ECCrypto
 
   def self.decrypt(hex_receiver_private_key : String, encrypted_message : String) : String
     dummy             : UInt8 = 0
-    decrypted_message : UInt8* = pointerof(dummy) 
+    decrypted_message : UInt8* = pointerof(dummy)
 
+    raise "Encrypted message must not be empty" unless encrypted_message.size > 0
     # pull the componente of the encrypted message apart
     chunks = encrypted_message.split("fx")
     raise "Message not encrypted by ECCrypto.encrypt" if chunks.size != 4
@@ -251,7 +253,7 @@ module ECCrypto
     status = LibECCrypto.decrypt_message(eccgrp_id, hex_receiver_private_key,
                                          epubk, epubk_len, iv, iv_len, tag, tag_len, ciphertext, ciphertext_len,
                                          pointerof(decrypted_message))
-    
+
     raise String.new(decrypted_message) unless status == 0
 
     return String.new(decrypted_message)