use sha256 as function encrypt key

Cargo.toml

@@ -11,4 +11,5 @@ anyhow = "1.0.86"
 clap = { version = "4.5.3", features = ["derive"] }
 memmap2 = "0.9.4"
 rust-crypto = "0.2.36"
+sha2 = "0.10.8"
 thiserror = "1.0.63"

README.md

@@ -171,15 +171,15 @@ $ objdump -d bin/res_enc
     1218:       89 7d fc                mov    %edi,-0x4(%rbp)
     121b:       48 89 75 f0             mov    %rsi,-0x10(%rbp)
     121f:       bf 01 00 00 00          mov    $0x1,%edi
-    1224:       e8 20 ff ff ff          call   1149 <�0,>
+    1224:       e8 20 ff ff ff          call   1149 <ӵ�>
     1229:       bf 01 00 00 00          mov    $0x1,%edi
     122e:       e8 6a ff ff ff          call   119d <fib>
     1233:       bf 05 00 00 00          mov    $0x5,%edi
-    1238:       e8 0c ff ff ff          call   1149 <�0,>
+    1238:       e8 0c ff ff ff          call   1149 <ӵ�>
     123d:       bf 05 00 00 00          mov    $0x5,%edi
     1242:       e8 56 ff ff ff          call   119d <fib>
     1247:       bf 0a 00 00 00          mov    $0xa,%edi
-    124c:       e8 f8 fe ff ff          call   1149 <�0,>
+    124c:       e8 f8 fe ff ff          call   1149 <ӵ�>
     1251:       bf 0a 00 00 00          mov    $0xa,%edi
     1256:       e8 42 ff ff ff          call   119d <fib>
     125b:       b8 00 00 00 00          mov    $0x0,%eax

src/obfus.rs

@@ -323,16 +323,10 @@ impl Obfuscator {
     }
 
     pub fn encrypt_function_name(&mut self, function: &str, key: &str) -> crate::error::Result<()> {
-        let mut key_bytes = [0; 32];
-        if key.len() > 32 {
-            return Err(crate::error::Error::InvalidOption(
-                "key length must be less than 32",
-            ));
-        }
-        for (i, byte) in key.bytes().enumerate() {
-            key_bytes[i] = byte;
-        }
-        let encryptor = crypto::aessafe::AesSafe256Encryptor::new(&key_bytes);
+        use sha2::digest::Digest as _;
+
+        let hash = sha2::Sha256::digest(key.as_bytes());
+        let encryptor = crypto::aessafe::AesSafe256Encryptor::new(&hash);
 
         let tmp_file = std::fs::OpenOptions::new()
             .read(true)