如何在Java中验证公钥和私钥对

您可以通过以下方式验证密钥对是否匹配

• 创建 挑战 (足够长的随机字节序列)
• 签署 挑战 私钥
• 正在验证 使用 公钥

这为您提供了足够高的置信度(几乎可以肯定),如果签名验证正常,则密钥对匹配,否则密钥对不匹配。

示例代码:

KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
keyGen.initialize(2048);

KeyPair keyPair = keyGen.generateKeyPair();
PublicKey publicKey = keyPair.getPublic();
PrivateKey privateKey = keyPair.getPrivate();

// create a challenge
byte[] challenge = new byte[10000];
ThreadLocalRandom.current().nextBytes(challenge);

// sign using the private key
Signature sig = Signature.getInstance("SHA256withRSA");
sig.initSign(privateKey);
sig.update(challenge);
byte[] signature = sig.sign();

// verify signature using the public key
sig.initVerify(publicKey);
sig.update(challenge);

boolean keyPairMatches = sig.verify(signature);

标记为正确的答案会浪费大量CPU周期。这个答案可以提高CPU效率:

KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
keyGen.initialize(2048);

KeyPair keyPair = keyGen.generateKeyPair();
RSAPrivateCrtKey privateKey = (RSAPrivateCrtKey) keyPair.getPrivate();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

// comment this out to verify the behavior when the keys are different
//keyPair = keyGen.generateKeyPair();
//publicKey = (RSAPublicKey) keyPair.getPublic();

boolean keyPairMatches = privateKey.getModulus().equals(publicKey.getModulus()) &&
    privateKey.getPublicExponent().equals(publicKey.getPublicExponent());