Fix fomratting

Signed-off-by: Dusan Borovcanin <[email protected]>

Author: dborovcanin

crypto/README.md

@@ -6,7 +6,7 @@
 - `aes_encrypt(string, string, string, string)` - return AES encrypted hex-encoded ciphertext
 - `aes_decrypt(string, string, string, string)` - return AES decrypted hex-encoded plain text
 
-AES support 3 modes: GCM, CBC, and CTR - first parameter is mode, second is key, third is initialization vector or nonce - depending on the mode, and forth is plain text or ciphertext.
+AES support 3 modes: GCM, CBC, and CTR - first parameter is mode, second is hex-encoded key, third is hex-encoded initialization vector or nonce - depending on the mode, and forth is hex-encoded plain text or ciphertext.
 
 ## Examples
 

crypto/aes.go

@@ -142,7 +142,10 @@ func decryptAES(m mode, key, init, ciphertext []byte) ([]byte, error) {
 		mode := cipher.NewCBCDecrypter(block, init)
 		plaintext := make([]byte, len(ciphertext))
 		mode.CryptBlocks(plaintext, ciphertext)
-		return unpad(plaintext, aes.BlockSize)
+		// Padding reversal is intentionally left to the application layer.
+		// On constrained devices with fixed-length payloads, handling padding here
+		// would introduce unnecessary overhead and processing load.
+		return plaintext, nil
 	case CTR:
 		stream := cipher.NewCTR(block, init)
 		plaintext := make([]byte, len(ciphertext))
@@ -158,19 +161,3 @@ func pad(data []byte, blockSize int) []byte {
 	padding := bytes.Repeat([]byte{byte(padLen)}, padLen)
 	return append(data, padding...)
 }
-
-func unpad(data []byte, blockSize int) ([]byte, error) {
-	if len(data) == 0 || len(data)%blockSize != 0 {
-		return nil, fmt.Errorf("invalid padding size")
-	}
-	padLen := int(data[len(data)-1])
-	if padLen == 0 || padLen > blockSize {
-		return nil, fmt.Errorf("invalid padding")
-	}
-	for i := 0; i < padLen; i++ {
-		if data[len(data)-1-i] != byte(padLen) {
-			return nil, fmt.Errorf("invalid padding byte")
-		}
-	}
-	return data[:len(data)-padLen], nil
-}

crypto/loader.go

@@ -5,7 +5,7 @@ import lua "github.com/yuin/gopher-lua"
 // Preload adds crypto to the given Lua state's package.preload table. After it
 // has been preloaded, it can be loaded using require:
 //
-//	local crypto = require("crypto")
+// local crypto = require("crypto")
 func Preload(L *lua.LState) {
 	L.PreloadModule("crypto", Loader)
 }

crypto/test/test_api.lua

@@ -82,12 +82,12 @@ function TestAESEncrypt(t)
             err = "failed to encrypt: incorrect GCM nonce size: 14, expected: 12",
         },
         {
-            data = "48656c6c6f20776f726c64", -- "Hello world" in hex
-            mode  = "cbc",
-            key = "86e15cbc1cbf510d8f2e51d4b63a2144",
-            init = "068bb92e032884ba8b260fa7d3a80005",
+            data     = "48656c6c6f20776f726c64", -- "Hello world" in hex
+            mode     = "cbc",
+            key      = "86e15cbc1cbf510d8f2e51d4b63a2144",
+            init     = "068bb92e032884ba8b260fa7d3a80005",
             expected = "dfba6f71cce4d4b76be301b577d9f095",
-            err = nil,
+            err      = nil,
         },
         {
             data = "48656c6c6f20776f726c64", -- "Hello world" in hex
@@ -162,7 +162,7 @@ function TestAESDecrypt(t)
             mode = "cbc",
             key = "86e15cbc1cbf510d8f2e51d4b63a2144",
             init = "068bb92e032884ba8b260fa7d3a80005",
-            expected = "48656c6c6f20776f726c64", -- "Hello world" in hex
+            expected = "48656c6c6f20776f726c640505050505", -- "Hello world" + padding in hex
             err = nil,
         },
         {