OpenSSLは通常、で指定されている独自のパスワードベースの鍵導出方法を使用しEVP_BytesToKeyます。以下のコードを参照してください。さらに、暗号文を複数行でbase 64として暗黙的にエンコードします。これは、メールメッセージの本文内で暗号文を送信するために必要です。
したがって、結果は擬似コードで次のようになります。
salt = random(8)
keyAndIV = BytesToKey(password, salt, 48)
key = keyAndIV[0..31]
iv = keyAndIV[32..47]
ct = AES-256-CBC-encrypt(key, iv, plaintext)
res = base64MimeEncode("Salted__" | salt | ct))
したがって、復号化は次のようになります。
(salt, ct) = base64MimeDecode(res)
key = keyAndIV[0..31]
iv = keyAndIV[32..47]
pt = AES-256-CBC-decrypt(key, iv, plaintext)
これは、次のようにJavaで実装できます。
import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.util.Arrays;
import java.util.List;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.bouncycastle.util.encoders.Base64;
public class OpenSSLDecryptor {
private static final Charset ASCII = Charset.forName("ASCII");
private static final int INDEX_KEY = 0;
private static final int INDEX_IV = 1;
private static final int ITERATIONS = 1;
private static final int ARG_INDEX_FILENAME = 0;
private static final int ARG_INDEX_PASSWORD = 1;
private static final int SALT_OFFSET = 8;
private static final int SALT_SIZE = 8;
private static final int CIPHERTEXT_OFFSET = SALT_OFFSET + SALT_SIZE;
private static final int KEY_SIZE_BITS = 256;
/**
* Thanks go to Ola Bini for releasing this source on his blog.
* The source was obtained from <a href="http://olabini.com/blog/tag/evp_bytestokey/">here</a> .
*/
public static byte[][] EVP_BytesToKey(int key_len, int iv_len, MessageDigest md,
byte[] salt, byte[] data, int count) {
byte[][] both = new byte[2][];
byte[] key = new byte[key_len];
int key_ix = 0;
byte[] iv = new byte[iv_len];
int iv_ix = 0;
both[0] = key;
both[1] = iv;
byte[] md_buf = null;
int nkey = key_len;
int niv = iv_len;
int i = 0;
if (data == null) {
return both;
}
int addmd = 0;
for (;;) {
md.reset();
if (addmd++ > 0) {
md.update(md_buf);
}
md.update(data);
if (null != salt) {
md.update(salt, 0, 8);
}
md_buf = md.digest();
for (i = 1; i < count; i++) {
md.reset();
md.update(md_buf);
md_buf = md.digest();
}
i = 0;
if (nkey > 0) {
for (;;) {
if (nkey == 0)
break;
if (i == md_buf.length)
break;
key[key_ix++] = md_buf[i];
nkey--;
i++;
}
}
if (niv > 0 && i != md_buf.length) {
for (;;) {
if (niv == 0)
break;
if (i == md_buf.length)
break;
iv[iv_ix++] = md_buf[i];
niv--;
i++;
}
}
if (nkey == 0 && niv == 0) {
break;
}
}
for (i = 0; i < md_buf.length; i++) {
md_buf[i] = 0;
}
return both;
}
public static void main(String[] args) {
try {
// --- read base 64 encoded file ---
File f = new File(args[ARG_INDEX_FILENAME]);
List<String> lines = Files.readAllLines(f.toPath(), ASCII);
StringBuilder sb = new StringBuilder();
for (String line : lines) {
sb.append(line.trim());
}
String dataBase64 = sb.toString();
byte[] headerSaltAndCipherText = Base64.decode(dataBase64);
// --- extract salt & encrypted ---
// header is "Salted__", ASCII encoded, if salt is being used (the default)
byte[] salt = Arrays.copyOfRange(
headerSaltAndCipherText, SALT_OFFSET, SALT_OFFSET + SALT_SIZE);
byte[] encrypted = Arrays.copyOfRange(
headerSaltAndCipherText, CIPHERTEXT_OFFSET, headerSaltAndCipherText.length);
// --- specify cipher and digest for EVP_BytesToKey method ---
Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");
MessageDigest md5 = MessageDigest.getInstance("MD5");
// --- create key and IV ---
// the IV is useless, OpenSSL might as well have use zero's
final byte[][] keyAndIV = EVP_BytesToKey(
KEY_SIZE_BITS / Byte.SIZE,
aesCBC.getBlockSize(),
md5,
salt,
args[ARG_INDEX_PASSWORD].getBytes(ASCII),
ITERATIONS);
SecretKeySpec key = new SecretKeySpec(keyAndIV[INDEX_KEY], "AES");
IvParameterSpec iv = new IvParameterSpec(keyAndIV[INDEX_IV]);
// --- initialize cipher instance and decrypt ---
aesCBC.init(Cipher.DECRYPT_MODE, key, iv);
byte[] decrypted = aesCBC.doFinal(encrypted);
String answer = new String(decrypted, ASCII);
System.out.println(answer);
} catch (BadPaddingException e) {
// AKA "something went wrong"
throw new IllegalStateException(
"Bad password, algorithm, mode or padding;" +
" no salt, wrong number of iterations or corrupted ciphertext.");
} catch (IllegalBlockSizeException e) {
throw new IllegalStateException(
"Bad algorithm, mode or corrupted (resized) ciphertext.");
} catch (GeneralSecurityException e) {
throw new IllegalStateException(e);
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
}
コードが文字セットとしてASCIIを指定していることに注意してください。使用する文字セットは、アプリケーション/端末/OSによって異なる場合があります。
一般に、OpenSSLにNIST承認のPBKDF2アルゴリズムを使用させる必要があります。これは、OpenSSLキー導出方法（反復回数1）の使用は安全ではないためです。これにより、OpenSSLとは異なるソリューションを使用せざるを得なくなる場合があります。パスワードベースの暗号化は本質的にかなり安全ではないことに注意してください。パスワードは、ランダムに生成された対称鍵よりもはるかに安全ではありません。
OpenSSL 1.1.0cは、一部の内部コンポーネントで使用されるダイジェストアルゴリズムを変更しました。以前は、MD5が使用され、1.1.0はSHA256に切り替えられました。EVP_BytesToKey変更がとの両方のコマンドに影響を与えないように注意してくださいopenssl enc。
のコマンドラインインターフェイスでダイジェストを明示的に指定し（-md md5下位互換性やsha-256上位互換性など）、Javaコードが同じダイジェストアルゴリズム（"MD5"または"SHA-256"ダッシュを含む）を使用していることを確認するのがおそらく最善です。この回答の情報も参照してください。
以下は、OpenSSLと互換性のある方法で任意のバイトストリームを暗号化/復号化するために使用できるOpenSSLPBEInputStreamとOpenSSLPBEOutputStreamです。
使用例：
// The original clear text bytes
byte[] originalBytes = ...
// Encrypt these bytes
char[] pwd = "thePassword".toCharArray();
ByteArrayOutputStream byteOS = new ByteArrayOutputStream();
OpenSSLPBEOutputStream encOS = new OpenSSLPBEOutputStream(byteOS, ALGORITHM, 1, pwd);
encOS.write(originalBytes);
encOS.flush();
byte[] encryptedBytes = byteOS.toByteArray();
// Decrypt the bytes
ByteArrayInputStream byteIS = new ByteArrayInputStream(encryptedBytes);
OpenSSLPBEInputStream encIS = new OpenSSLPBEInputStream(byteIS, ALGORITHM, 1, pwd);
ALGORITHM（JDKクラスのみを使用）は、「PBEWithMD5AndDES」、「PBEWithMD5AndTripleDES」、「PBEWithSHA1AndDESede」、「PBEWithSHA1AndRC2_40」になります。
元のポスターの「opensslaes-256-cbc-a-salt -in password.txt -out password.txt.enc」を処理するには、クラスパスにバウンスキャッスルを追加し、algorthm="PBEWITHMD5AND256BITAES-CBC-OPENSSL"を使用します。
/* Add BC provider, and fail fast if BC provider is not in classpath for some reason */
Security.addProvider(new BouncyCastleProvider());
依存関係：
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk16</artifactId>
<version>1.44</version>
</dependency>
入力ストリーム：
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.io.IOException;
import java.io.InputStream;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
public class OpenSSLPBEInputStream extends InputStream {
private final static int READ_BLOCK_SIZE = 64 * 1024;
private final Cipher cipher;
private final InputStream inStream;
private final byte[] bufferCipher = new byte[READ_BLOCK_SIZE];
private byte[] bufferClear = null;
private int index = Integer.MAX_VALUE;
private int maxIndex = 0;
public OpenSSLPBEInputStream(final InputStream streamIn, String algIn, int iterationCount, char[] password)
throws IOException {
this.inStream = streamIn;
try {
byte[] salt = readSalt();
cipher = OpenSSLPBECommon.initializeCipher(password, salt, Cipher.DECRYPT_MODE, algIn, iterationCount);
} catch (InvalidKeySpecException | NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeyException | InvalidAlgorithmParameterException e) {
throw new IOException(e);
}
}
@Override
public int available() throws IOException {
return inStream.available();
}
@Override
public int read() throws IOException {
if (index > maxIndex) {
index = 0;
int read = inStream.read(bufferCipher);
if (read != -1) {
bufferClear = cipher.update(bufferCipher, 0, read);
}
if (read == -1 || bufferClear == null || bufferClear.length == 0) {
try {
bufferClear = cipher.doFinal();
} catch (IllegalBlockSizeException | BadPaddingException e) {
bufferClear = null;
}
}
if (bufferClear == null || bufferClear.length == 0) {
return -1;
}
maxIndex = bufferClear.length - 1;
}
return bufferClear[index++] & 0xff;
}
private byte[] readSalt() throws IOException {
byte[] headerBytes = new byte[OpenSSLPBECommon.OPENSSL_HEADER_STRING.length()];
inStream.read(headerBytes);
String headerString = new String(headerBytes, OpenSSLPBECommon.OPENSSL_HEADER_ENCODE);
if (!OpenSSLPBECommon.OPENSSL_HEADER_STRING.equals(headerString)) {
throw new IOException("unexpected file header " + headerString);
}
byte[] salt = new byte[OpenSSLPBECommon.SALT_SIZE_BYTES];
inStream.read(salt);
return salt;
}
}
出力ストリーム：
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.io.IOException;
import java.io.OutputStream;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
public class OpenSSLPBEOutputStream extends OutputStream {
private static final int BUFFER_SIZE = 5 * 1024 * 1024;
private final Cipher cipher;
private final OutputStream outStream;
private final byte[] buffer = new byte[BUFFER_SIZE];
private int bufferIndex = 0;
public OpenSSLPBEOutputStream(final OutputStream outputStream, String algIn, int iterationCount,
char[] password) throws IOException {
outStream = outputStream;
try {
/* Create and use a random SALT for each instance of this output stream. */
byte[] salt = new byte[PBECommon.SALT_SIZE_BYTES];
new SecureRandom().nextBytes(salt);
cipher = OpenSSLPBECommon.initializeCipher(password, salt, Cipher.ENCRYPT_MODE, algIn, iterationCount);
/* Write header */
writeHeader(salt);
} catch (InvalidKeySpecException | NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeyException | InvalidAlgorithmParameterException e) {
throw new IOException(e);
}
}
@Override
public void write(int b) throws IOException {
buffer[bufferIndex] = (byte) b;
bufferIndex++;
if (bufferIndex == BUFFER_SIZE) {
byte[] result = cipher.update(buffer, 0, bufferIndex);
outStream.write(result);
bufferIndex = 0;
}
}
@Override
public void flush() throws IOException {
if (bufferIndex > 0) {
byte[] result;
try {
result = cipher.doFinal(buffer, 0, bufferIndex);
outStream.write(result);
} catch (IllegalBlockSizeException | BadPaddingException e) {
throw new IOException(e);
}
bufferIndex = 0;
}
}
@Override
public void close() throws IOException {
flush();
outStream.close();
}
private void writeHeader(byte[] salt) throws IOException {
outStream.write(OpenSSLPBECommon.OPENSSL_HEADER_STRING.getBytes(OpenSSLPBECommon.OPENSSL_HEADER_ENCODE));
outStream.write(salt);
}
}
小さな一般的なクラス：
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
class OpenSSLPBECommon {
protected static final int SALT_SIZE_BYTES = 8;
protected static final String OPENSSL_HEADER_STRING = "Salted__";
protected static final String OPENSSL_HEADER_ENCODE = "ASCII";
protected static Cipher initializeCipher(char[] password, byte[] salt, int cipherMode,
final String algorithm, int iterationCount) throws NoSuchAlgorithmException, InvalidKeySpecException,
InvalidKeyException, NoSuchPaddingException, InvalidAlgorithmParameterException {
PBEKeySpec keySpec = new PBEKeySpec(password);
SecretKeyFactory factory = SecretKeyFactory.getInstance(algorithm);
SecretKey key = factory.generateSecret(keySpec);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(cipherMode, key, new PBEParameterSpec(salt, iterationCount));
return cipher;
}
}
Kotlinの場合：
package io.matthewnelson.java_crypto
import java.util.*
import javax.crypto.Cipher
import javax.crypto.SecretKeyFactory
import javax.crypto.spec.IvParameterSpec
import javax.crypto.spec.PBEKeySpec
import javax.crypto.spec.SecretKeySpec
class OpenSSL {
/**
* Will decrypt a string value encrypted by OpenSSL v 1.1.1+ using the following cmds from terminal:
*
* echo "Hello World!" | openssl aes-256-cbc -e -a -p -salt -pbkdf2 -iter 15739 -k qk4aX-EfMUa-g4HdF-fjfkU-bbLNx-15739
*
* Terminal output:
* salt=CC73B7D29FE59CE1
* key=31706F84185EA4B5E8E040F2C813F79722F22996B48B82FF98174F887A9B9993
* iv =1420310D41FD7F48E5D8722B9AC1C8DD
* U2FsdGVkX1/Mc7fSn+Wc4XLwDsmLdR8O7K3bFPpCglA=
* */
fun decrypt_AES256CBC_PBKDF2_HMAC_SHA256(
password: String,
hashIterations: Int,
encryptedString: String
): String {
val encryptedBytes = Base64.getDecoder().decode(encryptedString)
// Salt is bytes 8 - 15
val salt = encryptedBytes.copyOfRange(8, 16)
// println("Salt: ${salt.joinToString("") { "%02X".format(it) }}")
// Derive 48 byte key
val keySpec = PBEKeySpec(password.toCharArray(), salt, hashIterations, 48 * 8)
val keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256")
val secretKey = keyFactory.generateSecret(keySpec)
// Decryption Key is bytes 0 - 31 of the derived key
val key = secretKey.encoded.copyOfRange(0, 32)
// println("Key: ${key.joinToString("") { "%02X".format(it) }}")
// Input Vector is bytes 32 - 47 of the derived key
val iv = secretKey.encoded.copyOfRange(32, 48)
// println("IV: ${iv.joinToString("") { "%02X".format(it) }}")
// Cipher Text is bytes 16 - end of the encrypted bytes
val cipherText = encryptedBytes.copyOfRange(16, encryptedBytes.lastIndex + 1)
// Decrypt the Cipher Text and manually remove padding after
val cipher = Cipher.getInstance("AES/CBC/NoPadding")
cipher.init(Cipher.DECRYPT_MODE, SecretKeySpec(key, "AES"), IvParameterSpec(iv))
val decrypted = cipher.doFinal(cipherText)
// println("Decrypted: ${decrypted.joinToString("") { "%02X".format(it) }}")
// Last byte of the decrypted text is the number of padding bytes needed to remove
val plaintext = decrypted.copyOfRange(0, decrypted.lastIndex + 1 - decrypted.last().toInt())
return plaintext.toString(Charsets.UTF_8)
}
}
ase-128-cbcは使用せず、ase-128-ecbを使用してください。
hashpwd =echo -n $password| openssl sha1 | sed 's#.*=\\s*##g' | cut -c 1-32
openssl enc -aes-128-ecb -salt -in -out -K $ hashpwd
Javaコードはここにあります：
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Arrays;
//openssl enc -nosalt -aes-128-ecb
// -in <input file>
// -out <output file>
// -K <16 bytes in hex, for example : "abc" can be hashed in SHA-1, the first 16 bytes in hex is a9993e364706816aba3e25717850c26c>
private final static String TRANSFORMATION = "AES"; // use aes-128-ecb in openssl
public static byte[] encrypt(String passcode, byte[] data) throws CryptographicException {
try {
Cipher cipher = Cipher.getInstance(TRANSFORMATION);
cipher.init(Cipher.ENCRYPT_MODE, genKeySpec(passcode));
return cipher.doFinal(data);
} catch (Exception ex) {
throw new CryptographicException("Error encrypting", ex);
}
}
public static String encryptWithBase64(String passcode, byte[] data) throws CryptographicException {
return new BASE64Encoder().encode(encrypt(passcode, data));
}
public static byte[] decrypt(String passcode, byte[] data) throws CryptographicException {
try {
Cipher dcipher = Cipher.getInstance(TRANSFORMATION);
dcipher.init(Cipher.DECRYPT_MODE, genKeySpec(passcode));
return dcipher.doFinal(data);
} catch (Exception e) {
throw new CryptographicException("Error decrypting", e);
}
}
public static byte[] decryptWithBase64(String passcode, String encrptedStr) throws CryptographicException {
try {
return decrypt(passcode, new BASE64Decoder().decodeBuffer(encrptedStr));
} catch (Exception e) {
throw new CryptographicException("Error decrypting", e);
}
}
public static SecretKeySpec genKeySpec(String passcode) throws UnsupportedEncodingException, NoSuchAlgorithmException {
byte[] key = passcode.getBytes("UTF-8");
MessageDigest sha = MessageDigest.getInstance("SHA-1");
key = sha.digest(key);
key = Arrays.copyOf(key, 16); // use only first 128 bit
return new SecretKeySpec(key, TRANSFORMATION);
}
jdk6とjdk8でテストされ、合格しました。