庆云网站seo,公司主页是什么意思,软文的目的是什么,最实用的上网网址一览表来源#xff1a;Java AES加密和解密_一名可爱的技术搬运工-CSDN博客 高级加密标准 #xff08;AES#xff0c;Rijndael#xff09;是一种分组密码加密和解密算法#xff0c;是全球使用最广泛的加密算法。 AES使用128、192或256位的密钥来处理128位的块。
本文向您展示了一…来源Java AES加密和解密_一名可爱的技术搬运工-CSDN博客 高级加密标准 AESRijndael是一种分组密码加密和解密算法是全球使用最广泛的加密算法。 AES使用128、192或256位的密钥来处理128位的块。
本文向您展示了一些Java AES加密和解密示例
AES字符串加密–加密和解密字符串。AES基于密码的加密–密钥将从给定的密码派生。AES文件加密。 基于密码。
在本文中我们重点介绍通过Galois Counter ModeGCM进行的256位AES加密。
GCM CTR Authentication.
进一步阅读 阅读本– NIST – Galois /计数器模式GCM的建议 不要使用AES电子密码本ECB模式 AES ECB模式或AES/ECB/PKCS5Padding 在Java中在语义上并不安全 – ECB加密的密文可能泄漏有关纯文本的信息。 这是关于为什么不应该使用ECB加密的讨论。 1. Java和AES加密输入。
在AES加密和解密中我们需要以下输入 AES加密最佳做法 不要重复使用具有相同密钥的IV。 1.1 IV初始值或初始向量它是随机字节通常为12个字节或16个字节。 在Java中我们可以使用SecureRandom生成随机IV。
// 16 bytes IVpublic static byte[] getRandomNonce() {byte[] nonce new byte[16];new SecureRandom().nextBytes(nonce);return nonce;}// 12 bytes IVpublic static byte[] getRandomNonce() {byte[] nonce new byte[12];new SecureRandom().nextBytes(nonce);return nonce;}1.2 AES密钥即AES-128或AES-256 。 在Java中我们可以使用KeyGenerator生成AES密钥。
// 256 bits AES secret keypublic static SecretKey getAESKey() throws NoSuchAlgorithmException {KeyGenerator keyGen KeyGenerator.getInstance(AES);keyGen.init(256, SecureRandom.getInstanceStrong());return keyGen.generateKey();}1.3从给定密码派生的AES密钥。 在Java中我们可以使用SecretKeyFactory和PBKDF2WithHmacSHA256从给定的密码生成AES密钥。
// AES key derived from a passwordpublic static SecretKey getAESKeyFromPassword(char[] password, byte[] salt)throws NoSuchAlgorithmException, InvalidKeySpecException {SecretKeyFactory factory SecretKeyFactory.getInstance(PBKDF2WithHmacSHA256);// iterationCount 65536// keyLength 256KeySpec spec new PBEKeySpec(password, salt, 65536, 256);SecretKey secret new SecretKeySpec(factory.generateSecret(spec).getEncoded(), AES);return secret;}我们使用salt来保护彩虹攻击它也是一个随机字节我们可以使用相同的1.1 getRandomNonce生成它。
1.4我们将上述方法分组为一个util类这样我们就不会一次又一次重复相同的代码。
CryptoUtils.java
package com.mkyong.crypto.utils;import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.util.ArrayList;
import java.util.List;public class CryptoUtils {public static byte[] getRandomNonce(int numBytes) {byte[] nonce new byte[numBytes];new SecureRandom().nextBytes(nonce);return nonce;}// AES secret keypublic static SecretKey getAESKey(int keysize) throws NoSuchAlgorithmException {KeyGenerator keyGen KeyGenerator.getInstance(AES);keyGen.init(keysize, SecureRandom.getInstanceStrong());return keyGen.generateKey();}// Password derived AES 256 bits secret keypublic static SecretKey getAESKeyFromPassword(char[] password, byte[] salt)throws NoSuchAlgorithmException, InvalidKeySpecException {SecretKeyFactory factory SecretKeyFactory.getInstance(PBKDF2WithHmacSHA256);// iterationCount 65536// keyLength 256KeySpec spec new PBEKeySpec(password, salt, 65536, 256);SecretKey secret new SecretKeySpec(factory.generateSecret(spec).getEncoded(), AES);return secret;}// hex representationpublic static String hex(byte[] bytes) {StringBuilder result new StringBuilder();for (byte b : bytes) {result.append(String.format(%02x, b));}return result.toString();}// print hex with block size splitpublic static String hexWithBlockSize(byte[] bytes, int blockSize) {String hex hex(bytes);// one hex 2 charsblockSize blockSize * 2;// better idea how to print this?ListString result new ArrayList();int index 0;while (index hex.length()) {result.add(hex.substring(index, Math.min(index blockSize, hex.length())));index blockSize;}return result.toString();}}package com.mkyong.crypto.utils;
2. AES加密和解密。
AES-GSM是使用最广泛的认证密码。 本示例将在Galois计数器模式GCM中使用256位AES加密和解密字符串。
AES-GCM输入
AES密钥256位IV – 96位12字节身份验证标签的长度以位为单位– 128位16字节
2.1在Java中我们使用AES/GCM/NoPadding表示AES-GCM算法。 对于加密的输出我们将16字节的IV前缀到加密的文本密文之前因为解密需要相同的IV。 如果IV是众所周知的可以吗 IV公开是可以的唯一的秘诀就是密钥对它保密并保密。 本示例将使用AES加密纯文本Hello World AES-GCM 然后将其解密回原始纯文本。
EncryptorAesGcm.java
package com.mkyong.crypto.encryptor;import com.mkyong.crypto.utils.CryptoUtils;import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.GCMParameterSpec;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;/*** AES-GCM inputs - 12 bytes IV, need the same IV and secret keys for encryption and decryption.* p* The output consist of iv, encrypted content, and auth tag in the following format:* output byte[] {i i i c c c c c c ...}* p* i IV bytes* c content bytes (encrypted content, auth tag)*/
public class EncryptorAesGcm {private static final String ENCRYPT_ALGO AES/GCM/NoPadding;private static final int TAG_LENGTH_BIT 128;private static final int IV_LENGTH_BYTE 12;private static final int AES_KEY_BIT 256;private static final Charset UTF_8 StandardCharsets.UTF_8;// AES-GCM needs GCMParameterSpecpublic static byte[] encrypt(byte[] pText, SecretKey secret, byte[] iv) throws Exception {Cipher cipher Cipher.getInstance(ENCRYPT_ALGO);cipher.init(Cipher.ENCRYPT_MODE, secret, new GCMParameterSpec(TAG_LENGTH_BIT, iv));byte[] encryptedText cipher.doFinal(pText);return encryptedText;}// prefix IV length IV bytes to cipher textpublic static byte[] encryptWithPrefixIV(byte[] pText, SecretKey secret, byte[] iv) throws Exception {byte[] cipherText encrypt(pText, secret, iv);byte[] cipherTextWithIv ByteBuffer.allocate(iv.length cipherText.length).put(iv).put(cipherText).array();return cipherTextWithIv;}public static String decrypt(byte[] cText, SecretKey secret, byte[] iv) throws Exception {Cipher cipher Cipher.getInstance(ENCRYPT_ALGO);cipher.init(Cipher.DECRYPT_MODE, secret, new GCMParameterSpec(TAG_LENGTH_BIT, iv));byte[] plainText cipher.doFinal(cText);return new String(plainText, UTF_8);}public static String decryptWithPrefixIV(byte[] cText, SecretKey secret) throws Exception {ByteBuffer bb ByteBuffer.wrap(cText);byte[] iv new byte[IV_LENGTH_BYTE];bb.get(iv);//bb.get(iv, 0, iv.length);byte[] cipherText new byte[bb.remaining()];bb.get(cipherText);String plainText decrypt(cipherText, secret, iv);return plainText;}public static void main(String[] args) throws Exception {String OUTPUT_FORMAT %-30s:%s;String pText Hello World AES-GCM, Welcome to Cryptography!;// encrypt and decrypt need the same key.// get AES 256 bits (32 bytes) keySecretKey secretKey CryptoUtils.getAESKey(AES_KEY_BIT);// encrypt and decrypt need the same IV.// AES-GCM needs IV 96-bit (12 bytes)byte[] iv CryptoUtils.getRandomNonce(IV_LENGTH_BYTE);byte[] encryptedText EncryptorAesGcm.encryptWithPrefixIV(pText.getBytes(UTF_8), secretKey, iv);System.out.println(\n------ AES GCM Encryption ------);System.out.println(String.format(OUTPUT_FORMAT, Input (plain text), pText));System.out.println(String.format(OUTPUT_FORMAT, Key (hex), CryptoUtils.hex(secretKey.getEncoded())));System.out.println(String.format(OUTPUT_FORMAT, IV (hex), CryptoUtils.hex(iv)));System.out.println(String.format(OUTPUT_FORMAT, Encrypted (hex) , CryptoUtils.hex(encryptedText)));System.out.println(String.format(OUTPUT_FORMAT, Encrypted (hex) (block 16), CryptoUtils.hexWithBlockSize(encryptedText, 16)));System.out.println(\n------ AES GCM Decryption ------);System.out.println(String.format(OUTPUT_FORMAT, Input (hex), CryptoUtils.hex(encryptedText)));System.out.println(String.format(OUTPUT_FORMAT, Input (hex) (block 16), CryptoUtils.hexWithBlockSize(encryptedText, 16)));System.out.println(String.format(OUTPUT_FORMAT, Key (hex), CryptoUtils.hex(secretKey.getEncoded())));String decryptedText EncryptorAesGcm.decryptWithPrefixIV(encryptedText, secretKey);System.out.println(String.format(OUTPUT_FORMAT, Decrypted (plain text), decryptedText));}}package com.mkyong.crypto.encryptor;
输出量
纯文本 Hello World AES-GCM
Terminal
------ AES GCM Encryption ------
Input (plain text) :Hello World AES-GCM
Key (hex) :603d87185bf855532f14a77a91ec7b025c004bf664e9f5c6e95613ee9577f436
IV (hex) :bdb271ce5235996a0709e09c
Encrypted (hex) :bdb271ce5235996a0709e09c2d03eefe319e9329768724755c56291aecaef88cd1e6bdf72b8c7b54d75a94e66b0cd3
Encrypted (hex) (block 16) :[bdb271ce5235996a0709e09c2d03eefe, 319e9329768724755c56291aecaef88c, d1e6bdf72b8c7b54d75a94e66b0cd3]------ AES GCM Decryption ------
Input (hex) :bdb271ce5235996a0709e09c2d03eefe319e9329768724755c56291aecaef88cd1e6bdf72b8c7b54d75a94e66b0cd3
Input (hex) (block 16) :[bdb271ce5235996a0709e09c2d03eefe, 319e9329768724755c56291aecaef88c, d1e6bdf72b8c7b54d75a94e66b0cd3]
Key (hex) :603d87185bf855532f14a77a91ec7b025c004bf664e9f5c6e95613ee9577f436
Decrypted (plain text) :Hello World AES-GCM------ AES GCM Encryption ------
纯文本 Hello World AES-GCM, Welcome to Cryptography!
Terminal
------ AES GCM Encryption ------
Input (plain text) :Hello World AES-GCM, Welcome to Cryptography!
Key (hex) :ddc24663d104e1c2f81f11aef98156503dafdc435f81e3ac3d705015ebab095c
IV (hex) :b05d6aedf023f73b9e1e2d11
Encrypted (hex) :b05d6aedf023f73b9e1e2d11f6f5137d971aea8c5cdd5b045e0960eb4408e0ee4635cccc2dfeec2c13a89bd400f659be82dc2329e9c36e3b032f38bd42296a8495ac840b0625c097d9
Encrypted (hex) (block 16) :[b05d6aedf023f73b9e1e2d11f6f5137d, 971aea8c5cdd5b045e0960eb4408e0ee, 4635cccc2dfeec2c13a89bd400f659be, 82dc2329e9c36e3b032f38bd42296a84, 95ac840b0625c097d9]------ AES GCM Decryption ------
Input (hex) :b05d6aedf023f73b9e1e2d11f6f5137d971aea8c5cdd5b045e0960eb4408e0ee4635cccc2dfeec2c13a89bd400f659be82dc2329e9c36e3b032f38bd42296a8495ac840b0625c097d9
Input (hex) (block 16) :[b05d6aedf023f73b9e1e2d11f6f5137d, 971aea8c5cdd5b045e0960eb4408e0ee, 4635cccc2dfeec2c13a89bd400f659be, 82dc2329e9c36e3b032f38bd42296a84, 95ac840b0625c097d9]
Key (hex) :ddc24663d104e1c2f81f11aef98156503dafdc435f81e3ac3d705015ebab095c
Decrypted (plain text) :Hello World AES-GCM, Welcome to Cryptography!------ AES GCM Encryption ------
3.基于AES密码的加密和解密。
对于基于密码的加密我们可以使用定义为RFC 8018的基于密码的密码规范PKCS从给定的密码生成密钥。
对于PKCS输入
密码您提供。盐–至少64位8字节随机字节。迭代计数–建议最小迭代计数为1,000。
什么是盐和迭代计数
salt会为给定的密码生成广泛的密钥集。 例如如果盐是128位则每个密码将有多达2 ^ 128个密钥。 因此它增加了彩虹攻击的难度。 此外攻击者为一个用户的密码构建的彩虹表对于另一用户变得毫无用处。iteration count增加了从密码生成密钥的成本因此增加了难度并减慢了攻击速度。
3.1对于加密的输出我们在密文前面加上12 bytes IV和password salt 因为我们需要相同的IV和密码盐用于密钥进行解密。 此外我们使用Base64编码器将加密的文本编码为字符串表示形式以便我们可以以字符串格式字节数组发送加密的文本或密文。 如果密码盐是众所周知的可以吗 与IV相同并且可以公开知道密码盐唯一的秘诀就是密钥并对其进行保密和保密。 EncryptorAesGcmPassword.java
package com.mkyong.crypto.encryptor;import com.mkyong.crypto.utils.CryptoUtils;import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.GCMParameterSpec;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Base64;/*** AES-GCM inputs - 12 bytes IV, need the same IV and secret keys for encryption and decryption.* p* The output consist of iv, passwords salt, encrypted content and auth tag in the following format:* output byte[] {i i i s s s c c c c c c ...}* p* i IV bytes* s Salt bytes* c content bytes (encrypted content)*/
public class EncryptorAesGcmPassword {private static final String ENCRYPT_ALGO AES/GCM/NoPadding;private static final int TAG_LENGTH_BIT 128; // must be one of {128, 120, 112, 104, 96}private static final int IV_LENGTH_BYTE 12;private static final int SALT_LENGTH_BYTE 16;private static final Charset UTF_8 StandardCharsets.UTF_8;// return a base64 encoded AES encrypted textpublic static String encrypt(byte[] pText, String password) throws Exception {// 16 bytes saltbyte[] salt CryptoUtils.getRandomNonce(SALT_LENGTH_BYTE);// GCM recommended 12 bytes iv?byte[] iv CryptoUtils.getRandomNonce(IV_LENGTH_BYTE);// secret key from passwordSecretKey aesKeyFromPassword CryptoUtils.getAESKeyFromPassword(password.toCharArray(), salt);Cipher cipher Cipher.getInstance(ENCRYPT_ALGO);// ASE-GCM needs GCMParameterSpeccipher.init(Cipher.ENCRYPT_MODE, aesKeyFromPassword, new GCMParameterSpec(TAG_LENGTH_BIT, iv));byte[] cipherText cipher.doFinal(pText);// prefix IV and Salt to cipher textbyte[] cipherTextWithIvSalt ByteBuffer.allocate(iv.length salt.length cipherText.length).put(iv).put(salt).put(cipherText).array();// string representation, base64, send this string to other for decryption.return Base64.getEncoder().encodeToString(cipherTextWithIvSalt);}// we need the same password, salt and iv to decrypt itprivate static String decrypt(String cText, String password) throws Exception {byte[] decode Base64.getDecoder().decode(cText.getBytes(UTF_8));// get back the iv and salt from the cipher textByteBuffer bb ByteBuffer.wrap(decode);byte[] iv new byte[IV_LENGTH_BYTE];bb.get(iv);byte[] salt new byte[SALT_LENGTH_BYTE];bb.get(salt);byte[] cipherText new byte[bb.remaining()];bb.get(cipherText);// get back the aes key from the same password and saltSecretKey aesKeyFromPassword CryptoUtils.getAESKeyFromPassword(password.toCharArray(), salt);Cipher cipher Cipher.getInstance(ENCRYPT_ALGO);cipher.init(Cipher.DECRYPT_MODE, aesKeyFromPassword, new GCMParameterSpec(TAG_LENGTH_BIT, iv));byte[] plainText cipher.doFinal(cipherText);return new String(plainText, UTF_8);}public static void main(String[] args) throws Exception {String OUTPUT_FORMAT %-30s:%s;String PASSWORD this is a password;String pText AES-GSM Password-Bases encryption!;String encryptedTextBase64 EncryptorAesGcmPassword.encrypt(pText.getBytes(UTF_8), PASSWORD);System.out.println(\n------ AES GCM Password-based Encryption ------);System.out.println(String.format(OUTPUT_FORMAT, Input (plain text), pText));System.out.println(String.format(OUTPUT_FORMAT, Encrypted (base64) , encryptedTextBase64));System.out.println(\n------ AES GCM Password-based Decryption ------);System.out.println(String.format(OUTPUT_FORMAT, Input (base64), encryptedTextBase64));String decryptedText EncryptorAesGcmPassword.decrypt(encryptedTextBase64, PASSWORD);System.out.println(String.format(OUTPUT_FORMAT, Decrypted (plain text), decryptedText));}}package com.mkyong.crypto.encryptor;
输出量
Terminal
------ AES GCM Password-based Encryption ------
Input (plain text) :AES-GSM Password-Bases encryption!
Encrypted (base64) :KmrvjnMusJTQo/hB7T5BvlQpvi3bVbdjpZP51NT7I/enrIfSQuDfSK6iXgdPzvUP2IE54mwrKiyHqMkG8224lRZ9tXHcclmdh98I8b3B------ AES GCM Password-based Decryption ------
Input (base64) :KmrvjnMusJTQo/hB7T5BvlQpvi3bVbdjpZP51NT7I/enrIfSQuDfSK6iXgdPzvUP2IE54mwrKiyHqMkG8224lRZ9tXHcclmdh98I8b3B
Decrypted (plain text) :AES-GSM Password-Bases encryption!------ AES GCM Password-based Encryption ------
3.2如果密码不匹配Java会抛出AEADBadTagException: Tag mismatch!
// change the password to something elseString decryptedText EncryptorAesGcmPassword.decrypt(encryptedTextBase64, other password);System.out.println(String.format(OUTPUT_FORMAT, Decrypted (plain text), decryptedText));// change the password to something else
输出量
Terminal
Exception in thread main javax.crypto.AEADBadTagException: Tag mismatch!at java.base/com.sun.crypto.provider.GaloisCounterMode.decryptFinal(GaloisCounterMode.java:623)at java.base/com.sun.crypto.provider.CipherCore.finalNoPadding(CipherCore.java:1118)at java.base/com.sun.crypto.provider.CipherCore.fillOutputBuffer(CipherCore.java:1055)at java.base/com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:855)at java.base/com.sun.crypto.provider.AESCipher.engineDoFinal(AESCipher.java:446)at java.base/javax.crypto.Cipher.doFinal(Cipher.java:2207)at com.mkyong.crypto.encryptor.EncryptorAesGcmPassword.decrypt(EncryptorAesGcmPassword.java:88)at com.mkyong.crypto.encryptor.EncryptorAesGcmPassword.main(EncryptorAesGcmPassword.java:109)Exception in thread main javax.crypto.AEADBadTagException: Tag mismatch!
4. AES文件加密和解密。
此示例是基于AES密码的文件加密。 想法是相同的但是我们需要一些IO类来处理资源或文件。
这是resources文件夹中的文本文件。
readme.txt
This is line 1.
This is line 2.
This is line 3.
This is line 4.
This is line 5.
This is line 9.
This is line 10.This is line 1.
4.1此示例类似于3.1 EncryptorAesGcmPassword.java 但有一些小的更改例如返回byte[]而不是base64编码的字符串。
public static byte[] encrypt(byte[] pText, String password) throws Exception {//...// prefix IV and Salt to cipher textbyte[] cipherTextWithIvSalt ByteBuffer.allocate(iv.length salt.length cipherText.length).put(iv).put(salt).put(cipherText).array();// it works, even if we save the based64 encoded string into a file.// return Base64.getEncoder().encodeToString(cipherTextWithIvSalt);// we save the byte[] into a file.return cipherTextWithIvSalt;}public static byte[] encrypt(byte[] pText, String password) throws Exception {
添加encryptFile和decryptFile工作与文件。
public static void encryptFile(String fromFile, String toFile, String password) throws Exception {// read a normal txt filebyte[] fileContent Files.readAllBytes(Paths.get(ClassLoader.getSystemResource(fromFile).toURI()));// encrypt with a passwordbyte[] encryptedText EncryptorAesGcmPasswordFile.encrypt(fileContent, password);// save a filePath path Paths.get(toFile);Files.write(path, encryptedText);}public static byte[] decryptFile(String fromEncryptedFile, String password) throws Exception {// read a filebyte[] fileContent Files.readAllBytes(Paths.get(fromEncryptedFile));return EncryptorAesGcmPasswordFile.decrypt(fileContent, password);}public static void encryptFile(
4.2从类路径中读取以上readme.txt文件对其进行加密然后将加密的数据保存到新文件c:\test\readme.encrypted.txt 。
String password password123;String fromFile readme.txt; // from resources folderString toFile c:\\test\\readme.encrypted.txt;// encrypt fileEncryptorAesGcmPasswordFile.encryptFile(fromFile, toFile, password);String password password123;
输出量 4.3读取加密的文件解密并打印输出。
String password password123;String toFile c:\\test\\readme.encrypted.txt;// decrypt filebyte[] decryptedText EncryptorAesGcmPasswordFile.decryptFile(toFile, password);String pText new String(decryptedText, UTF_8);System.out.println(pText);String password password123;
输出量
Terminal
This is line 1.
This is line 2.
This is line 3.
This is line 4.
This is line 5.
This is line 9.
This is line 10.This is line 1.
PS AES图像加密是相同的概念。
下载源代码 $ git clone https://github.com/mkyong/core-java $ cd java-crypto 让我知道文章是否需要改进。 谢谢。
参考文献
维基百科–密码JavaDoc维基百科–密码块链接CBC维基百科-Galois / Counter ModeGCMOracle – KeyGenerator算法JavaDocJava –如何生成随机的12个字节为什么不应该使用ECB加密Spring Security加密模块维基百科– PBKDF2RFC 8018 – PKCSJava –如何连接和分割字节数组Java安全标准算法名称NIST – Galois /计数器模式GCM的建议翻译自: Java AES encryption and decryption - Mkyong.com
