Fix encryption key normalization

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "encrypted_images"
-version = "1.4.0"
+version = "1.4.1"
 edition = "2021"
 description = "Encrypt Text to Images and decrypt text from images."
 authors = ["Bruce Bates | https://www.linkedin.com/in/bruce-bates/"]

src/decryption/text.rs

@@ -30,16 +30,13 @@
   /// ```
   use subtle::ConstantTimeEq;
   use openssl::symm::{decrypt, Cipher};
-  use crate::encryption::text::hmac::calculate_hmac;
+  use crate::encryption::text::{hmac::calculate_hmac, normalize_key};
   use base64::{Engine as _, engine::{self, general_purpose}, alphabet};
   const CUSTOM_ENGINE: engine::GeneralPurpose =
       engine::GeneralPurpose::new(&alphabet::STANDARD, general_purpose::PAD);
   pub fn decrypts(encoded_result: &str, key: Option<&str>) -> Option<String> {
     let key = key.unwrap_or("welovenfts");
-    let mut padded_key = key.as_bytes().to_vec();
-    while padded_key.len() < 16 {
-        padded_key.push(b'\0');
-    }
+    let padded_key = normalize_key(key);
     let result_bytes = CUSTOM_ENGINE.decode(encoded_result).ok()?;
     let iv = &result_bytes[..16];
     let hmac = &result_bytes[16..48];

src/encryption/text.rs

@@ -65,6 +65,14 @@
   const CUSTOM_ENGINE: engine::GeneralPurpose =
     engine::GeneralPurpose::new(&alphabet::STANDARD, general_purpose::PAD);
 
+  pub(crate) fn normalize_key(key: &str) -> Vec<u8> {
+    let mut padded_key = key.as_bytes().to_vec();
+    while padded_key.len() < 16 {
+        padded_key.push(b'\0');
+    }
+    padded_key.truncate(16);
+    padded_key
+  }
 
   pub fn encrypts(input: &str, key: Option<&str>, strength: Option<&str>) -> Option<String> {
     let cipher = Cipher::aes_128_cbc();
@@ -79,11 +87,7 @@
       let random_bytes = generate_random_bytes(num_bytes);
       iv = CUSTOM_ENGINE.encode(random_bytes);
     }
-    let mut padded_key = key.as_bytes().to_vec();
-    while padded_key.len() < 16 {
-        padded_key.push(b'\0');
-    }
-    padded_key.truncate(16);
+    let padded_key = normalize_key(key);
     let ciphertext = encrypt(cipher, &padded_key, Some(iv.as_bytes()), input.as_bytes()).unwrap();
     let hmac = calculate_hmac(&ciphertext, &padded_key);
     if hmac.ct_eq(&calculate_hmac(&ciphertext, &padded_key)).unwrap_u8() == 1 {
@@ -114,4 +118,3 @@
     rng.fill(&mut random_bytes[..]);
     random_bytes
   }
-

src/lib.rs

@@ -50,6 +50,24 @@
       assert_eq!(decrypted, Some(input.to_string()));
     }
 
+    #[test]
+    fn test_encrypts_decrypts_with_long_key() {
+      let input = "ThisIsJustaTestString";
+      let key = Some("this_key_is_longer_than_sixteen_bytes");
+      let encrypted = encrypts(input, key.clone(), None);
+      let decrypted = decrypts(encrypted.as_ref().unwrap(), key);
+      assert_eq!(decrypted, Some(input.to_string()));
+    }
+
+    #[test]
+    fn test_encrypts_decrypts_with_unicode_key() {
+      let input = "ThisIsJustaTestString";
+      let key = Some("密码密码密码密码");
+      let encrypted = encrypts(input, key.clone(), None);
+      let decrypted = decrypts(encrypted.as_ref().unwrap(), key);
+      assert_eq!(decrypted, Some(input.to_string()));
+    }
+
     #[test]
     fn test_encrypts_decrypts_without_key() {
       // Input data to encrypt