只要你留在 Java 中（我的意思是你不想与其他系统交换（加密的）私钥）我建议加密编码的私钥 - 这样你完全使用 Java 的内置资源。尝试使用“加密的 PEM 格式”需要使用像 Bouncy Castle 这样的外部库。
以下解决方案将生成一个 ECDSA 密钥对并打印出编码后的私钥。该字节数组使用随机生成的（32 字节长）密钥加密，该密钥用作 GCM 模式操作函数中 AES 的输入；输出是一个由 3 部分连接而成的字符串：
(Base64) nonce : (Base64) ciphertext : (Base64) gcmTag
优化的版本可以在字节数组的基础上使用直接连接，但由于该函数取自实际项目，因此我以这种方式使用它。
我省略了字符串的保存和加载部分 - 该字符串提供给解密函数，直接将（加载的）私钥作为输出。这个加载键也被打印出来以表明两个键是相等的。
这是示例输出：
Write and read encrypted ECDSA private keys
ecdsaPrivateKey:
3041020100301306072a8648ce3d020106082a8648ce3d030107042730250201010420c07c0af37716b11ac76780287026935190cb3575c1475a02da687b45adfed8b4
encryptedKey: 2adcp+3lEvS8zhc5:5n5UyHThiIQweqXxJfI479qIwv4m7nm/gNeEDeXcd15zVQCTuER2Hn/SPQUM9TbPFHkdh9CWwYI74lbCyV1AJng62g==:HRWiBgME/SsyHQBvvfdTEg==
ecdsaPrivateKeyLoaded:
3041020100301306072a8648ce3d020106082a8648ce3d030107042730250201010420c07c0af37716b11ac76780287026935190cb3575c1475a02da687b45adfed8b4
以下代码没有异常处理，仅用于教育目的：
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.ByteBuffer;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;
public class EncryptedEcdsaPrivateKey {
public static void main(String[] args)
throws NoSuchAlgorithmException, IllegalBlockSizeException, InvalidKeyException,
BadPaddingException, InvalidAlgorithmParameterException, NoSuchPaddingException,
InvalidKeySpecException {
System.out.println("Write and read encrypted ECDSA private keys");
// step 1 generate an ecdsa key pair
KeyPair ecdsaKeyPair = generateEcdsaKeyPair(256);
PrivateKey ecdsaPrivateKey = ecdsaKeyPair.getPrivate();
System.out.println("ecdsaPrivateKey:\n" + bytesToHex(ecdsaPrivateKey.getEncoded()));
// step 2 generate a randomly generated AES-256-GCM key
byte[] randomKey = generateRandomAesKey();
// step 3 encrypt the encoded key with the randomly generated AES-256-GCM key
String encryptedKey = aesGcmEncryptToBase64(randomKey, ecdsaPrivateKey.getEncoded());
System.out.println("encryptedKey: " + encryptedKey);
// step 4 save the key to file
// ... omitted
// step 5 load the key from file
// ... omitted
// step 6 decrypt the encrypted data to an ecdsa public key
PrivateKey ecdsaPrivateKeyLoaded = aesGcmDecryptFromBase64(randomKey, encryptedKey);
System.out.println("ecdsaPrivateKeyLoaded:\n" + bytesToHex(ecdsaPrivateKeyLoaded.getEncoded()));
}
public static KeyPair generateEcdsaKeyPair(int keylengthInt)
throws NoSuchAlgorithmException {
KeyPairGenerator keypairGenerator = KeyPairGenerator.getInstance("EC");
SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
keypairGenerator.initialize(keylengthInt, random);
return keypairGenerator.generateKeyPair();
}
private static byte[] generateRandomAesKey() {
SecureRandom secureRandom = new SecureRandom();
byte[] key = new byte[32];
secureRandom.nextBytes(key);
return key;
}
private static byte[] generateRandomNonce() {
SecureRandom secureRandom = new SecureRandom();
byte[] nonce = new byte[12];
secureRandom.nextBytes(nonce);
return nonce;
}
private static String aesGcmEncryptToBase64(byte[] key, byte[] data)
throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException,
InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
byte[] nonce = generateRandomNonce();
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(16 * 8, nonce);
Cipher cipher = Cipher.getInstance("AES/GCM/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, gcmParameterSpec);
byte[] ciphertextWithTag = cipher.doFinal(data);
byte[] ciphertext = new byte[(ciphertextWithTag.length-16)];
byte[] gcmTag = new byte[16];
System.arraycopy(ciphertextWithTag, 0, ciphertext, 0, (ciphertextWithTag.length - 16));
System.arraycopy(ciphertextWithTag, (ciphertextWithTag.length-16), gcmTag, 0, 16);
String nonceBase64 = base64Encoding(nonce);
String ciphertextBase64 = base64Encoding(ciphertext);
String gcmTagBase64 = base64Encoding(gcmTag);
return nonceBase64 + ":" + ciphertextBase64 + ":" + gcmTagBase64;
}
private static PrivateKey aesGcmDecryptFromBase64(byte[] key, String data)
throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException,
InvalidKeyException, BadPaddingException, IllegalBlockSizeException, InvalidKeySpecException {
String[] parts = data.split(":", 0);
byte[] nonce = base64Decoding(parts[0]);
byte[] ciphertextWithoutTag = base64Decoding(parts[1]);
byte[] gcmTag = base64Decoding(parts[2]);
byte[] encryptedData = concatenateByteArrays(ciphertextWithoutTag, gcmTag);
Cipher cipher = Cipher.getInstance("AES/GCM/PKCS5Padding");
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(16 * 8, nonce);
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, gcmParameterSpec);
byte[] encodedEcdsaKey = cipher.doFinal(encryptedData);
KeyFactory keyFactory = KeyFactory.getInstance("EC");
PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(encodedEcdsaKey);
return keyFactory.generatePrivate(privateKeySpec);
}
private static String base64Encoding(byte[] input) {
return Base64.getEncoder().encodeToString(input);
}
private static byte[] base64Decoding(String input) {
return Base64.getDecoder().decode(input);
}
private static String bytesToHex(byte[] bytes) {
StringBuffer result = new StringBuffer();
for (byte b : bytes) result.append(Integer.toString((b & 0xff) + 0x100, 16).substring(1));
return result.toString();
}
public static byte[] concatenateByteArrays(byte[] a, byte[] b) {
return ByteBuffer
.allocate(a.length + b.length)
.put(a).put(b)
.array();
}
}