Java實(shí)現(xiàn)非對稱加密的三種方法
1. 簡介
公開密鑰密碼學(xué)(英語:Public-key cryptography)也稱非對稱式密碼學(xué)(英語:Asymmetric cryptography)是密碼學(xué)的一種算法,它需要兩個密鑰,一個是公開密鑰,另一個是私有密鑰;公鑰用作加密,私鑰則用作解密。使用公鑰把明文加密后所得的密文,只能用相對應(yīng)的私鑰才能解密并得到原本的明文,最初用來加密的公鑰不能用作解密。由于加密和解密需要兩個不同的密鑰,故被稱為非對稱加密;不同于加密和解密都使用同一個密鑰的對稱加密。公鑰可以公開,可任意向外發(fā)布;私鑰不可以公開,必須由用戶自行嚴(yán)格秘密保管,絕不透過任何途徑向任何人提供,也不會透露給被信任的要通信的另一方。
基于公開密鑰加密的特性,它還能提供數(shù)字簽名的功能,使電子文件可以得到如同在紙本文件上親筆簽署的效果。公開密鑰基礎(chǔ)建設(shè)透過信任數(shù)字證書認(rèn)證機(jī)構(gòu)的根證書、及其使用公開密鑰加密作數(shù)字簽名核發(fā)的公開密鑰認(rèn)證,形成信任鏈架構(gòu),已在TLS實(shí)現(xiàn)并在萬維網(wǎng)的HTTP以HTTPS、在電子郵件的SMTP以SMTPS或STARTTLS引入。
在現(xiàn)實(shí)世界上可作比擬的例子是,一個傳統(tǒng)保管箱,開門和關(guān)門都是使用同一條鑰匙,這是對稱加密;而一個公開的郵箱,投遞口是任何人都可以寄信進(jìn)去的,這可視為公鑰;而只有信箱主人擁有鑰匙可以打開信箱,這就視為私鑰。
非對稱加密過程:
此流程圖顯示非對稱加密過程是單向的,其中一條密鑰加密后只能用相對應(yīng)的另一條密鑰解密。
2. 非對稱加密算法–DH(密鑰交換)
密鑰長度 | 默認(rèn) | 工作模式 | 填充方式 | 實(shí)現(xiàn)方 |
---|---|---|---|---|
512~1024(64倍數(shù)) | 1024 | 無 | 無 | JDK |
DH加解密應(yīng)用:
package com.bity.dh; import org.apache.commons.codec.binary.Base64; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.KeyAgreement; import javax.crypto.NoSuchPaddingException; import javax.crypto.SecretKey; import javax.crypto.interfaces.DHPublicKey; import javax.crypto.spec.DHParameterSpec; import java.nio.charset.StandardCharsets; import java.security.InvalidAlgorithmParameterException; import java.security.InvalidKeyException; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.PrivateKey; import java.security.PublicKey; import java.security.spec.InvalidKeySpecException; import java.security.spec.X509EncodedKeySpec; import java.util.Objects; import static java.lang.System.*; /** * <p>Title: JdkDh</p > * <p>Description: DH非對稱算法實(shí)現(xiàn) </p > * <p>Company: http://www.agree.com</p > * <p>Project: security</p > * * @author <a href="mailto:weiqi@agree.com.cn" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >WEIQI</a> * @version 1.0 * @date 2022-04-27 19:51 */ public class JdkDh { private static final String SRC = "I'm DH encryption algorithm"; public static void main(String[] args) { // 解決 Unsupported secret key algorithm: DES 異常 System.getProperties().setProperty("jdk.crypto.KeyAgreement.legacyKDF", "true"); jdkDh(); } private static void jdkDh() { try { // 初始化發(fā)送方密鑰 KeyPairGenerator senderKeyPairGenerator = KeyPairGenerator.getInstance("DH"); senderKeyPairGenerator.initialize(512); KeyPair senderKeyPair = senderKeyPairGenerator.generateKeyPair(); // 發(fā)送方密鑰,發(fā)送給接收方(可以通過文件、優(yōu)盤、網(wǎng)絡(luò)等...) byte[] senderPublicKeyEnc = senderKeyPair.getPublic().getEncoded(); // 初始化接收方密鑰,注意在實(shí)際環(huán)境中接收方和發(fā)送方肯定不會在一個函數(shù)中 KeyFactory keyFactory = KeyFactory.getInstance("DH"); X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(senderPublicKeyEnc); PublicKey receiverPublicKey = keyFactory.generatePublic(x509EncodedKeySpec); DHParameterSpec dhParameterSpec = ((DHPublicKey)receiverPublicKey).getParams(); KeyPairGenerator receiverKeyPairGenerator = KeyPairGenerator.getInstance("DH"); receiverKeyPairGenerator.initialize(dhParameterSpec); KeyPair receiverKeyPair = receiverKeyPairGenerator.generateKeyPair(); PrivateKey receiverPrivateKey = receiverKeyPair.getPrivate(); byte[] receiverPublicKeyEnc = receiverKeyPair.getPublic().getEncoded(); // 構(gòu)建密鑰 KeyAgreement receiverKeyAgreement = KeyAgreement.getInstance("DH"); receiverKeyAgreement.init(receiverPrivateKey); receiverKeyAgreement.doPhase(receiverPublicKey, true); SecretKey receiverSecretKey = receiverKeyAgreement.generateSecret("DES"); KeyFactory senderKeyFactory = KeyFactory.getInstance("DH"); x509EncodedKeySpec = new X509EncodedKeySpec(receiverPublicKeyEnc); PublicKey senderPublicKey = senderKeyFactory.generatePublic(x509EncodedKeySpec); KeyAgreement senderKeyAgreement = KeyAgreement.getInstance("DH"); senderKeyAgreement.init(senderKeyPair.getPrivate()); senderKeyAgreement.doPhase(senderPublicKey, true); SecretKey senderSecretKey = senderKeyAgreement.generateSecret("DES"); if (Objects.equals(receiverSecretKey, senderSecretKey)) { out.println("雙方密鑰相同"); } // 加密 Cipher cipher = Cipher.getInstance("DES"); cipher.init(Cipher.ENCRYPT_MODE, senderSecretKey); byte[] result = cipher.doFinal(SRC.getBytes(StandardCharsets.UTF_8)); out.println("jdk dh encryption is : " + Base64.encodeBase64String(result)); // 解密 cipher.init(Cipher.DECRYPT_MODE, receiverSecretKey); result = cipher.doFinal(result); out.println("jdk dh decrypt is : " + new String(result)); } catch (NoSuchAlgorithmException | InvalidKeySpecException | InvalidAlgorithmParameterException | InvalidKeyException | NoSuchPaddingException | IllegalBlockSizeException | BadPaddingException e) { e.printStackTrace(); } } }
運(yùn)行結(jié)果:
雙方密鑰相同
jdk dh encryption is : Be3LeXqV/q1PDEbpH62LL129gaV5Og0Eo3GY9e00B4o=
jdk dh decrypt is : I'm DH encryption algorithm
注意:由于JDK8 update 161之后,DH的密鑰長度至少為512位,但DES算法密鑰不能達(dá)到這樣的長度,所以運(yùn)行會拋出Unsupported secret key algorithm: DES異常。解決辦法有兩種如下:
- 在代碼中加如下代碼:
System.getProperties().setProperty("jdk.crypto.KeyAgreement.legacyKDF", "true");
在啟動的時候添加JVM變量:-Djdk.crypto.KeyAgreement.legacyKDF=true
3. 非對稱加密算法–RSA
RSA加密算法是一種非對稱加密算法,在公開密鑰加密和電子商業(yè)中被廣泛使用。RSA是由羅納德·李維斯特(Ron Rivest)、阿迪·薩莫爾(Adi Shamir)和倫納德·阿德曼(Leonard Adleman)在1977年一起提出的。當(dāng)時他們?nèi)硕荚诼槭±砉W(xué)院工作。RSA 就是他們?nèi)诵帐祥_頭字母拼在一起組成的。
對極大整數(shù)做因數(shù)分解的難度決定了 RSA 算法的可靠性。換言之,對一極大整數(shù)做因數(shù)分解愈困難,RSA 算法愈可靠。假如有人找到一種快速因數(shù)分解的算法的話,那么用 RSA 加密的信息的可靠性就會極度下降。但找到這樣的算法的可能性是非常小的。今天只有短的 RSA 鑰匙才可能被強(qiáng)力方式破解。到2020年為止,世界上還沒有任何可靠的攻擊RSA算法的方式。只要其鑰匙的長度足夠長,用RSA加密的信息實(shí)際上是不能被破解的。
RSA算法加密實(shí)現(xiàn):
package com.bity.rsa; import org.apache.commons.codec.binary.Base64; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.NoSuchPaddingException; import java.nio.charset.StandardCharsets; import java.security.InvalidKeyException; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.PrivateKey; import java.security.PublicKey; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.InvalidKeySpecException; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import static java.lang.System.*; /** * <p>Title: JdkRsa</p > * <p>Description: RSA非對稱加密算法實(shí)現(xiàn) </p > * <p>Company: http://www.agree.com</p > * <p>Project: security</p > * * @author <a href="mailto:weiqi@agree.com.cn" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >WEIQI</a> * @version 1.0 * @date 2022-04-27 21:38 */ public class JdkRsa { private static final String SRC = "I'm RSA encryption algorithm"; public static void main(String[] args) { jdkRsa(); } /** * JDK-RSA算法實(shí)現(xiàn) * * @author: <a href="mailto:weiqi@agree.com.cn" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >WEIQI</a> * @date: 2022-04-28 0:15 */ private static void jdkRsa() { try { // 初始化密鑰 KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA"); keyPairGenerator.initialize(512); KeyPair keyPair = keyPairGenerator.generateKeyPair(); RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic(); RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate(); out.println("public key is : " + Base64.encodeBase64String(rsaPublicKey.getEncoded())); out.println("private key is : " + Base64.encodeBase64String(rsaPrivateKey.getEncoded())); // 私鑰加密,公鑰解密 -- 加密 PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded()); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec); Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, privateKey); byte[] result = cipher.doFinal(SRC.getBytes(StandardCharsets.UTF_8)); out.println("私鑰加密,公鑰解密 -- 加密 : " + Base64.encodeBase64String(result)); // 私鑰加密,公鑰解密 -- 解密 X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded()); keyFactory = KeyFactory.getInstance("RSA"); PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec); cipher.init(Cipher.DECRYPT_MODE, publicKey); result = cipher.doFinal(result); out.println("私鑰加密,公鑰解密 -- 解密 : " + new String(result)); // 公鑰加密,私鑰解密 -- 加密 cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] res = cipher.doFinal(SRC.getBytes(StandardCharsets.UTF_8)); out.println("公鑰加密,私鑰解密 -- 加密 : " + Base64.encodeBase64String(res)); // 公鑰加密,私鑰解密 -- 解密 cipher.init(Cipher.DECRYPT_MODE, privateKey); res = cipher.doFinal(res); out.println("公鑰加密,私鑰解密 -- 解密 : " + new String(res)); } catch (NoSuchAlgorithmException | InvalidKeySpecException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException e) { e.printStackTrace(); } } }
運(yùn)行結(jié)果:
public key is : MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAIfDTXqCrjGHP9tCmLujavsngP8nqSHIl/JkFN8ZmQEcn48xzSXdijEG8Ssgm3SkDWICT0cW9wf3mZ+UkVxLx90CAwEAAQ==
private key is : MIIBVQIBADANBgkqhkiG9w0BAQEFAASCAT8wggE7AgEAAkEAh8NNeoKuMYc/20KYu6Nq+yeA/yepIciX8mQU3xmZARyfjzHNJd2KMQbxKyCbdKQNYgJPRxb3B/eZn5SRXEvH3QIDAQABAkASyfa5E8jj1eICiE72+QDfTXJO3cBMiqRsyWkSD0rbmlL/Qv1xDDQonWM58sIR6DOBWQZ+uXbkL1VtOuZ9sgfBAiEA9IxhRwkTYA1GVUKmgZPX+7CsfUmIZi8P/r9/C29XQZUCIQCOHtBkIOupaTLPv3A4yznEidygfbL8nrLV2Xhf6wVrKQIhAJ+RdewPDPhw0QLTIaiNWrIdXv/FWl4quUolk/VXKl1dAiASpbpkGOmy7cmr9otr+EZZIlmfeT695LjEVGd19mlcmQIhAJfua+j3/PT0+z0nPIaGDvczviyl5SxmDo79rfMNpi10
私鑰加密,公鑰解密 -- 加密 : AiYjJSlGlz5x86mwVW/wjieG/uJsoLEqF+xRcPLzq2HL7yIrSrE3oT4wibrvUDR6kp37eHvFaAT+/wVYCreVvg==
私鑰加密,公鑰解密 -- 解密 : I'm RSA encryption algorithm
公鑰加密,私鑰解密 -- 加密 : Io2diORtKbeTz5eOOziHrqZKzS1K19U4t3YPydhM4w2LrzW7bJK/d4DQrWTBAhg8rt28OjbGcJfqd1w8MMy4iw==
公鑰加密,私鑰解密 -- 解密 : I'm RSA encryption algorithm
從上面例子可以看出RSA算法是支持私鑰加密、公鑰解密和公鑰加密、私鑰解密的算法。RSA也是唯一被廣泛接受并實(shí)現(xiàn)的非對稱加密算法,從某種程度來說,RSA已經(jīng)成為非對稱加密算法的一個標(biāo)準(zhǔn)了。
RSA數(shù)據(jù)加密傳輸圖示:
4、非對稱加密算法–EIGamal
在密碼學(xué)中,ElGamal加密算法是一個基于迪菲-赫爾曼密鑰交換的非對稱加密算法。它在1985年由塔希爾·蓋莫爾提出。GnuPG和PGP等很多密碼學(xué)系統(tǒng)中都應(yīng)用到了ElGamal算法。
ElGamal加密算法由三部分組成:密鑰生成、加密和解密。
ElGamal算法加解密應(yīng)用:
package com.bity.eigamal; import org.apache.commons.codec.binary.Base64; import org.bouncycastle.jce.provider.BouncyCastleProvider; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.NoSuchPaddingException; import javax.crypto.spec.DHParameterSpec; import java.nio.charset.StandardCharsets; import java.security.AlgorithmParameterGenerator; import java.security.AlgorithmParameters; import java.security.InvalidAlgorithmParameterException; import java.security.InvalidKeyException; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.PrivateKey; import java.security.PublicKey; import java.security.SecureRandom; import java.security.Security; import java.security.spec.InvalidKeySpecException; import java.security.spec.InvalidParameterSpecException; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import static java.lang.System.out; /** * <p>Title: BouncyCastleEiGamal</p > * <p>Description: ElGamal加密算法實(shí)現(xiàn) </p > * <p>Company: http://www.agree.com</p > * <p>Project: security</p > * * @author <a href="mailto:weiqi@agree.com.cn" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >WEIQI</a> * @version 1.0 * @date 2022-04-28 0:38 */ public class BouncyCastleElGamal { private static final String SRC = "I'm ElGamal encryption algorithm"; public static void main(String[] args) { bcElGamal(); } private static void bcElGamal() { try { Security.addProvider(new BouncyCastleProvider()); AlgorithmParameterGenerator algorithmParameterGenerator = AlgorithmParameterGenerator .getInstance("ElGamal"); algorithmParameterGenerator.init(256); AlgorithmParameters algorithmParameters = algorithmParameterGenerator.generateParameters(); DHParameterSpec dhParameterSpec = algorithmParameters.getParameterSpec(DHParameterSpec.class); // 初始化密鑰 KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("ElGamal"); keyPairGenerator.initialize(dhParameterSpec, new SecureRandom()); KeyPair keyPair = keyPairGenerator.generateKeyPair(); PublicKey elGamalPublicKey = keyPair.getPublic(); PrivateKey elGamalPrivateKey = keyPair.getPrivate(); out.println("public key is : " + Base64.encodeBase64String(elGamalPublicKey.getEncoded())); out.println("private key is : " + Base64.encodeBase64String(elGamalPrivateKey.getEncoded())); // 公鑰加密,私鑰解密 -- 加密 X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(elGamalPublicKey.getEncoded()); KeyFactory keyFactory = KeyFactory.getInstance("ElGamal"); PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec); Cipher cipher = Cipher.getInstance("ElGamal"); cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] result = cipher.doFinal(SRC.getBytes(StandardCharsets.UTF_8)); out.println("私鑰加密,公鑰解密 -- 解密 : " + Base64.encodeBase64String(result)); // 公鑰加密,私鑰解密 -- 解密 PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(elGamalPrivateKey.getEncoded()); keyFactory = KeyFactory.getInstance("ElGamal"); PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec); cipher.init(Cipher.DECRYPT_MODE, privateKey); result = cipher.doFinal(result); out.println("私鑰加密,公鑰解密 -- 加密 : " + new String(result)); } catch (NoSuchAlgorithmException | InvalidKeySpecException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException | InvalidParameterSpecException | InvalidAlgorithmParameterException e) { e.printStackTrace(); } } }
運(yùn)行結(jié)果:
public key is : MHYwTwYGKw4HAgEBMEUCIQCxvT1SNSrVl1/8KpvPhaE1MKiaXOHWk5SACDd39SfnHwIgQ5O8oKi9mIKhEDOCKwvYB+mozFgvmuoipw/ZDl6xCicDIwACIBh0K6bn2mtdvmiSMJj/HDlotAGOmTRFMZs+PFoIobQG
private key is : MHgCAQAwTwYGKw4HAgEBMEUCIQCxvT1SNSrVl1/8KpvPhaE1MKiaXOHWk5SACDd39SfnHwIgQ5O8oKi9mIKhEDOCKwvYB+mozFgvmuoipw/ZDl6xCicEIgIge9eM9ELM12n6bQKkj8iBtIXjvPeN5mwX9clNriqfSsA=
私鑰加密,公鑰解密 -- 解密 : e39h4LkKXQn1EIXdDkIxmWiB2pwgO5dZJcNfSmlXqS07SrW1VSLrx0L3RhdWm8hPLaqBZieR5quU/7oTzH/uuA==
私鑰加密,公鑰解密 -- 加密 : I'm ElGamal encryption algorithm
ElGamal數(shù)據(jù)加密傳輸圖示:
5. 總結(jié)
對稱密碼是指在加密和解密時使用同一個密鑰的方式,公鑰密碼則是指在加密和解密時使用不同密鑰的方式。
對稱密鑰加密牽涉到密鑰管理的問題,尤其是密鑰交換,它需要通信雙方在通信之前先透過另一個安全的渠道交換共享的密鑰,才可以安全地把密文透過不安全的渠道發(fā)送;對稱密鑰一旦被竊,其所作的加密將即時失效;而在互聯(lián)網(wǎng),如果通信雙方分隔異地而素未謀面,則對稱加密事先所需要的“安全渠道”變得不可行;非對稱加密則容許加密公鑰隨便散布,解密的私鑰不發(fā)往任何用戶,只在單方保管;如此,即使公鑰在網(wǎng)上被截獲,如果沒有與其匹配的私鑰,也無法解密,極為適合在互聯(lián)網(wǎng)上使用。
另一方面,公鑰解密的特性可以形成數(shù)字簽名,使數(shù)據(jù)和文件受到保護(hù)并可信賴;如果公鑰透過數(shù)字證書認(rèn)證機(jī)構(gòu)簽授成為電子證書,更可作為數(shù)字身份的認(rèn)證,這都是對稱密鑰加密無法實(shí)現(xiàn)的。不過,公鑰加密在在計算上相當(dāng)復(fù)雜,性能欠佳、遠(yuǎn)遠(yuǎn)不比對稱加密;因此,在一般實(shí)際情況下,往往通過公鑰加密來隨機(jī)創(chuàng)建臨時的對稱秘鑰,亦即對話鍵,然后才通過對稱加密來傳輸大量、主體的數(shù)據(jù)。
6 案例
6.1 案例1
package com.test; import javax.crypto.Cipher; import java.nio.charset.StandardCharsets; import java.security.*; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import java.util.Base64; public class MyTest02 { public static void main(String[] args) throws Exception { MyTest02 myTest02 = new MyTest02(); myTest02.test1(); //生成密鑰 String jm = myTest02.test2(); //通過公鑰加密 myTest02.test3(jm); //通過私鑰解密 } public void test1() throws NoSuchAlgorithmException { // 初始化密鑰 KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA"); keyPairGenerator.initialize(512); KeyPair keyPair = keyPairGenerator.generateKeyPair(); RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic(); RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate(); System.out.println("public key is : " + Base64.getEncoder().encodeToString(rsaPublicKey.getEncoded())); System.out.println("private key is : " + Base64.getEncoder().encodeToString(rsaPrivateKey.getEncoded())); } public String test2() throws Exception { String SRC = "I'm RSA encryption algorithm"; String pubKey = "MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAIOz/OOCWjqI/6gssHGA/cHiJnR3hNdp230g1x7Y/aWzFc8WrQnjlX4v0PdEOphfkt8CtdzgDAlz4gMTLkLdU30CAwEAAQ=="; byte[] pubKeyDecode = Base64.getDecoder().decode(pubKey); X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(pubKeyDecode); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec); Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] res = cipher.doFinal(SRC.getBytes(StandardCharsets.UTF_8)); System.out.println("公鑰加密,私鑰解密 -- 加密 : " + Base64.getEncoder().encodeToString(res)); return Base64.getEncoder().encodeToString(res); } public void test3 (String data) throws Exception { String pvtKey = "MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAg7P844JaOoj/qCywcYD9weImdHeE12nbfSDXHtj9pbMVzxatCeOVfi/Q90Q6mF+S3wK13OAMCXPiAxMuQt1TfQIDAQABAkAbcnUvjMj1DfwJtlaHMRSxRUoyV34tznfZmfB7E0m5MEwfCMECzVKVtnmPpl3abbSt7UFwarvhnhhqfMM3Z9BBAiEA7ny1zoW04a/KM7VJRprOtkC3IQzjiyPl8aeoaseuvIkCIQCNX9t9K6GmSpwPLdBDtfk+Krk0qfiZaB9tEOhtG4hqVQIhAIriiaZJ63r7OtA+JPw/L16n9X4D2YewUjsXHleBDluxAiB9bkjs22NGiPfBN+KJ0NBcacd8hDl+0jTfrZqqAz2bKQIgUokJPDnwtnWVvWEwAK2wkDHkpIuvVRiG0HxNhS/ZDQA="; byte[] pvtDecoder = Base64.getDecoder().decode(pvtKey); PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(pvtDecoder); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec); Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, privateKey); byte[] decode = Base64.getDecoder().decode(data); byte[] res = cipher.doFinal(decode); System.out.printf("公鑰加密,私鑰解密 -- 解密: " + new String(res)); }
6.2 案例2
import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.PrivateKey; import java.security.PublicKey; import java.util.Base64; import javax.crypto.Cipher; public class RSAEncryptionExample { public static void main(String[] args) throws Exception { String data = "Hello, world!"; KeyPair keyPair = KeyPairGenerator.getInstance("RSA").generateKeyPair(); PublicKey publicKey = keyPair.getPublic(); PrivateKey privateKey = keyPair.getPrivate(); Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] encryptedData = cipher.doFinal(data.getBytes()); System.out.println(Base64.getEncoder().encodeToString(encryptedData)); cipher.init(Cipher.DECRYPT_MODE, privateKey); byte[] decryptedData = cipher.doFinal(encryptedData); System.out.println(new String(decryptedData)); } }
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