Java equivalent of an OpenSSL AES CBC encryption
At this time openssl version 1.1.0f-3 requires a digest function SHA-256. Without this it fails to decode.
Following is a Java program to decrypt the above OPENSSL encryption (it requires Java 8):
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.MessageDigest;
import java.util.Arrays;
import java.util.Base64;
import java.util.Base64.Decoder;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
public class TestAesDecrypt {
public static void main(final String[] args) throws Exception {
final byte[] pass = "testpass".getBytes(StandardCharsets.US_ASCII);
final byte[] magic = "Salted__".getBytes(StandardCharsets.US_ASCII);
final String inFile = "e:/t/e.txt";
String source = new String(Files.readAllBytes(Paths.get(inFile)),
StandardCharsets.US_ASCII);
source = source.replaceAll("\\s", "");
final Decoder decoder = Base64.getDecoder();
final byte[] inBytes = decoder.decode(source);
final byte[] shouldBeMagic = Arrays.copyOfRange(inBytes, 0,
magic.length);
if (!Arrays.equals(shouldBeMagic, magic)) {
System.out.println("Bad magic number");
return;
}
final byte[] salt = Arrays.copyOfRange(inBytes, magic.length,
magic.length + 8);
final byte[] passAndSalt = concat(pass, salt);
byte[] hash = new byte[0];
byte[] keyAndIv = new byte[0];
for (int i = 0; i < 3; i++) {
final byte[] data = concat(hash, passAndSalt);
final MessageDigest md = MessageDigest.getInstance("MD5");
hash = md.digest(data);
keyAndIv = concat(keyAndIv, hash);
}
final byte[] keyValue = Arrays.copyOfRange(keyAndIv, 0, 32);
final byte[] iv = Arrays.copyOfRange(keyAndIv, 32, 48);
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
final SecretKeySpec key = new SecretKeySpec(keyValue, "AES");
cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));
final byte[] clear = cipher.doFinal(inBytes, 16, inBytes.length - 16);
final String clearText = new String(clear, StandardCharsets.ISO_8859_1);
System.out.println(clearText);
}
private static byte[] concat(final byte[] a, final byte[] b) {
final byte[] c = new byte[a.length + b.length];
System.arraycopy(a, 0, c, 0, a.length);
System.arraycopy(b, 0, c, a.length, b.length);
return c;
}
}
This question has an accepted answer which is a bit old, however this seems to be something that comes up again and again. I have 2 projects were we communicate with 3rd parties and the cipher is OpenSSL AES with a pre-shared key.
I have used the not-yet-common-ssl library. However it appears to be stuck at version 0.3.x and with no releases in almost 2 years, not any mailing list traffic or visible development I have to conclude that this is essentially dead.
Based on some additional stackoverflow questions I did find both Spring Security and Encryptor4j both of which seem to offer some reasonably packaged text encoding. However attempting to get Spring Security's Encryptors to work at decoding a known encoded text string failed for me, I am guessing that the IV and Key generation used by OpenSSL are simply not supported in the supplied implementation.
By examining the code above, as well as a known working C# and PHP implementation, I was able to come up with a utility class that is currently passing my tests for interoperability. Generally I'd greatly prefer to use a known library, but if there is one I have been unable to locate it. The class (https://gist.github.com/rrsIPOV/4d0f6be7c58173c16e9edf9f97c7d7f2) is as follows:
import groovy.transform.CompileStatic;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.MessageDigest;
import java.security.SecureRandom;
import static java.nio.charset.StandardCharsets.*
/**
* Mimics the OpenSSL AES Cipher options for encrypting and decrypting messages using a shared key (aka password) with symetric ciphers.
*/
@CompileStatic
class OpenSslAes {
/** OpenSSL's magic initial bytes. */
private static final String SALTED_STR = "Salted__";
private static final byte[] SALTED_MAGIC = SALTED_STR.getBytes(US_ASCII);
static String encryptAndURLEncode(String password, String clearText) {
String encrypted = encrypt(password, clearText);
return URLEncoder.encode(encrypted, UTF_8.name() );
}
/**
*
* @param password The password / key to encrypt with.
* @param data The data to encrypt
* @return A base64 encoded string containing the encrypted data.
*/
static String encrypt(String password, String clearText) {
final byte[] pass = password.getBytes(US_ASCII);
final byte[] salt = (new SecureRandom()).generateSeed(8);
final byte[] inBytes = clearText.getBytes(UTF_8);
final byte[] passAndSalt = array_concat(pass, salt);
byte[] hash = new byte[0];
byte[] keyAndIv = new byte[0];
for (int i = 0; i < 3 && keyAndIv.length < 48; i++) {
final byte[] hashData = array_concat(hash, passAndSalt);
final MessageDigest md = MessageDigest.getInstance("MD5");
hash = md.digest(hashData);
keyAndIv = array_concat(keyAndIv, hash);
}
final byte[] keyValue = Arrays.copyOfRange(keyAndIv, 0, 32);
final byte[] iv = Arrays.copyOfRange(keyAndIv, 32, 48);
final SecretKeySpec key = new SecretKeySpec(keyValue, "AES");
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(iv));
byte[] data = cipher.doFinal(inBytes);
data = array_concat(array_concat(SALTED_MAGIC, salt), data);
return Base64.getEncoder().encodeToString( data );
}
/**
* @see http://stackoverflow.com/questions/32508961/java-equivalent-of-an-openssl-aes-cbc-encryption for what looks like a useful answer. The not-yet-commons-ssl also has an implementation
* @param password
* @param source The encrypted data
* @return
*/
static String decrypt(String password, String source) {
final byte[] pass = password.getBytes(US_ASCII);
final byte[] inBytes = Base64.getDecoder().decode(source);
final byte[] shouldBeMagic = Arrays.copyOfRange(inBytes, 0, SALTED_MAGIC.length);
if (!Arrays.equals(shouldBeMagic, SALTED_MAGIC)) {
throw new IllegalArgumentException("Initial bytes from input do not match OpenSSL SALTED_MAGIC salt value.");
}
final byte[] salt = Arrays.copyOfRange(inBytes, SALTED_MAGIC.length, SALTED_MAGIC.length + 8);
final byte[] passAndSalt = array_concat(pass, salt);
byte[] hash = new byte[0];
byte[] keyAndIv = new byte[0];
for (int i = 0; i < 3 && keyAndIv.length < 48; i++) {
final byte[] hashData = array_concat(hash, passAndSalt);
final MessageDigest md = MessageDigest.getInstance("MD5");
hash = md.digest(hashData);
keyAndIv = array_concat(keyAndIv, hash);
}
final byte[] keyValue = Arrays.copyOfRange(keyAndIv, 0, 32);
final SecretKeySpec key = new SecretKeySpec(keyValue, "AES");
final byte[] iv = Arrays.copyOfRange(keyAndIv, 32, 48);
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));
final byte[] clear = cipher.doFinal(inBytes, 16, inBytes.length - 16);
return new String(clear, UTF_8);
}
private static byte[] array_concat(final byte[] a, final byte[] b) {
final byte[] c = new byte[a.length + b.length];
System.arraycopy(a, 0, c, 0, a.length);
System.arraycopy(b, 0, c, a.length, b.length);
return c;
}
}