此代码生成一对公/私钥：
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
keyGen.initialize(1024);
KeyPair keypair = keyGen.genKeyPair();
PrivateKey privateKey = keypair.getPrivate();
PublicKey publicKey = keypair.getPublic();
我想知道的是你通常如何存储公钥：
选项1：存储字节
byte[] privateKeyBytes = privateKey.getEncoded();
byte[] publicKeyBytes = publicKey.getEncoded();
// ... write to file
// convert bytes back to public/private keys
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec);
EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(publicKeyBytes);
PublicKey publicKey = keyFactory.generatePublic(publicKeySpec);
我不喜欢的是将代码绑定到具体的实现,如PKCS8EncodedKeySpec和X509EncodedKeySpec.
选项2：存储模数和指数
KeyFactory fact = KeyFactory.getInstance("RSA");
RSAPublicKeySpec pub = fact.getKeySpec(publicKey,RSAPublicKeySpec.class);
RSAPrivateKeySpec priv = fact.getKeySpec(privateKey,RSAPrivateKeySpec.class);
// store modulus and exponent as BigIntegers
BigInteger modulus = pub.getModulus());
BigInteger exponent = pub.getPublicExponent());
// ... write to file
// recreate public key (the same applies to the private key)
RSAPublicKeySpec keySpec = new RSAPublicKeySpec(modulus,exponent);
KeyFactory fact = KeyFactory.getInstance("RSA");
PublicKey pubKey = fact.generatePublic(keySpec);
第二个选项更容易实现,但我不知道它是否可能性能较差.
任何建议？
解决方法
在我们的应用程序中,我们以DER格式存储公钥和私钥,以便在java之外更容易地使用和操作.在我们的例子中,私钥没有密码.
将私钥转换为更容易在java中使用的东西：
openssl pkcs8 -topk8 -nocrypt -in key.pem -inform PEM -out key.der -outform DER
然后,您可以直接通过以下方式获取RSA私钥：
public static RSAPrivateKey getPrivateKey(File privateKeyFile) throws IOException,GeneralSecurityException {
byte[] keyBytes = new byte[(int)privateKeyFile.length()];
FileInputStream fis = new FileInputStream(privateKeyFile);
fis.read(keyBytes);
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
RSAPrivateKey privKey = (RSAPrivateKey) keyFactory.generatePrivate(spec);
return privKey;
}
公钥是相似的：
openssl rsa -in private.pem -pubout -outform DER -out public.der
并阅读它：
public static RSAPublicKey getPublicKey(File publicKeyFile) throws IOException,GeneralSecurityException {
byte[] keyBytes = new byte[(int)publicKeyFile.length()];
FileInputStream fis = new FileInputStream(publicKeyFile);
fis.read(keyBytes);
X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory factory = KeyFactory.getInstance("RSA");
RSAPublicKey pubKey = (RSAPublicKey)factory.generatePublic(publicKeySpec);
return pubKey;
}
许多人存储然后密钥库.为了我们的目的,我们需要使用几种不同语言在多个应用程序之间共享相同的密钥,并且不想在磁盘上复制文件.
