[NodeMCU] Lua Crypto Package and interface with Java program using AES-ECB

NodeMCU is an eLua based firmware for the ESP8266 WiFi SOC from Espressif.
NodeMCU support encrypt and decrypt functions which are in crypto packages.

http://nodemcu.readthedocs.io/en/dev/en/modules/crypto/
This is manual for Crypto package.

crypto.encrypt()

Encrypts Lua strings.

Syntax

crypto.encrypt(algo, key, plain [, iv])

Parameters

• algo the name of the encryption algorithm to use, one of
  • "AES-ECB" for 128-bit AES in ECB mode
  • "AES-CBC" for 128-bit AES in CBC mode
• key the encryption key as a string; for AES encryption this MUST be 16 bytes long
• plain the string to encrypt; it will be automatically zero-padded to a 16-byte boundary if necessary
• iv the initilization vector, if using AES-CBC; defaults to all-zero if not given

Returns

The encrypted data as a binary string. For AES this is always a multiple of 16 bytes in length.

Crypto package AES-ECB using no padding. So you should make 16 multiple bytes array from plain text. And NodeMCU use EUCKR encoding in crypto package.

NodeMCU

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key = "1234567890abcdef" cipher = crypto.encrypt("AES-ECB", key, "Hi, I'm secret!") print(crypto.toBase64(cipher)) cipher = crypto.encrypt("AES-ECB", key, "가나다라마바사") print(crypto.toBase64(cipher))

Result

LQ95s23+t6PK0mmokJFSYg==
w9kOL6y40iVqhuGdWt6vLw==

Java

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public static void main( String[] args) throws Exception { String keyValue = "1234567890abcdef"; String encryptedText1 = "LQ95s23+t6PK0mmokJFSYg=="; String encryptedText2 = "w9kOL6y40iVqhuGdWt6vLw=="; java.nio.charset.Charset charset = java.nio.charset.Charset.forName( "euckr"); java.security.Key key = new javax.crypto.spec.SecretKeySpec( keyValue.getBytes( charset), "AES"); javax.crypto.Cipher cipher = Cipher.getInstance( "AES/ECB/NoPadding"); cipher.init( Cipher.DECRYPT_MODE, key); System.out.println( "DecryptedText1=" + new String( cipher.doFinal( org.apache.commons.codec.binary.Base64.decodeBase64( encryptedText1.getBytes( charset))), charset)); System.out.println( "DecryptedText2=" + new String( cipher.doFinal( org.apache.commons.codec.binary.Base64.decodeBase64( encryptedText2.getBytes( charset))), charset)); }

Result