62 lines
1.9 KiB
Java
62 lines
1.9 KiB
Java
package com.secure.demo.crypto;
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import java.security.KeyFactory;
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import java.security.PublicKey;
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import java.security.spec.X509EncodedKeySpec;
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import java.util.Base64;
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import javax.crypto.Cipher;
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/**
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* RSA 工具类
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*
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* 与 Android 端 DeviceCrypto 配套：
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* - Android Keystore 生成 RSA-2048 密钥对
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* - 私钥在 TEE 中不可导出
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* - 公钥上传服务端，用于加密下发数据
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*
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* 用途：
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* - 加密 Recovery Token（设备恢复时下发）
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* - 加密 DEK（恢复后逐张照片下发）
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*/
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public class RsaUtil {
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private static final String KEY_ALGO = "RSA";
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private static final String TRANSFORMATION = "RSA/ECB/OAEPWithSHA-256AndMGF1Padding";
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private RsaUtil() {}
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/**
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* Base64 公钥 → PublicKey 对象
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*/
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public static PublicKey publicKeyFromBase64(String publicKeyBase64) {
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try {
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byte[] keyBytes = Base64.getDecoder().decode(publicKeyBase64);
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X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
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KeyFactory kf = KeyFactory.getInstance(KEY_ALGO);
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return kf.generatePublic(spec);
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} catch (Exception e) {
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throw new RuntimeException("Parse RSA public key failed", e);
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}
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}
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/**
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* 用设备 RSA 公钥加密数据
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*/
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public static byte[] encryptWithPublicKey(byte[] data, PublicKey publicKey) {
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try {
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Cipher cipher = Cipher.getInstance(TRANSFORMATION);
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cipher.init(Cipher.ENCRYPT_MODE, publicKey);
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return cipher.doFinal(data);
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} catch (Exception e) {
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throw new RuntimeException("RSA encrypt failed", e);
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}
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}
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/**
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* 用设备 RSA 公钥加密 → Base64 字符串
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*/
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public static String encryptBase64(byte[] data, PublicKey publicKey) {
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return Base64.getEncoder().encodeToString(encryptWithPublicKey(data, publicKey));
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}
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}
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