SHA1WithRSA 解密

SHA1WithRSA 是一种数字签名算法，不是加密算法，所以无法进行解密操作。它通常用于验证数字证书、软件包等的完整性和真实性。如果您需要解密 RSA 加密的数据，请使用 RSA 解密算法。以下是 Java 中使用 RSA 解密数据的示例代码：

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;

import javax.crypto.Cipher;

public class RSADecryptionExample {

    public static void main(String[] args) throws Exception {

        // 私钥字符串
        String privateKeyStr = "MIICdQIBADANBgkqhkiG9w0BAQEFAASCAl8wggJbAgEAAoGBAM+X/fxOc0T5lqHt"
                + "Q4AtYFVQ5fzP+Y7V7rRv7md1q9jvJfOlZ1t9EgulD5lCY3vLmLwZPsFzE6GkW9V"
                + "FwWQ0nVNLyZjyjy+9gMv3W7ZJ1d6kH8r5VleNyrKzLrQ7Vz7f7zW4Kry2j8NNTd"
                + "BZJWdQVQoGxASs8jXcGdH/z7eOZ9AgMBAAECgYEAiUWzRzGJx1KQIIPV7ZioG9W"
                + "n+Cp9tQlXoJm9SdNkYhLH4Hm6VvWQ8LkxJZy3d6P3zNokTtU5p1hsMvHl5C8Pp4"
                + "WAMH5K+I3L3J6tj8y4ZvJ4qfG2WQ+HgY1w2iIzGQVyJZTkaJkfJe7nVd0yA8H+/"
                + "4LWkXO8CnS8Zb+5J0r0M1F3z5IqCECQQD4O3H8Lro7Zp8Il6+cxJQ3Yw9tC9d9S"
                + "TfRASzLWJyD3qB5gKlE7vNXXL1rWJ6n8Fw1e1i2fOjO6gXnU5mLQ+5WTAkEA2Jt"
                + "dLlL0Q2BdP3pLwNFpi+EJk8XAcYpq2pKg3rMhnD7CnWJcVZK1inTq4yMMYRV7fZ"
                + "ejFJc6bSDlRG2jPvUwJBAJr6XJv6XDs/7ZDgE1/8+I2oKzNUiOQLqjU9A/4n2g"
                + "5R4u1S7i3SGnSvSN2aC9h7+9PnJ2xg/7VbqkTQYz1tsCQQDGo9jIxI7Vr4DyDy2"
                + "FQvKUvR/4/tDBg2ZzF8Fj+REOreD5Q5p4rWVSiRfsZ5A6OQ9Q0yqPbZD8Jd1J5m"
                + "zuIrAkEAo54+SH1NVWsJYNMDQgFfB/QvWDw5WjRq1G2xYzsKzOgCj6t6oHvO1b6"
                + "psJx4IwWZ7oTzEwUx8vqQpwwkaPvJg==";

        // 将私钥字符串转换为 PrivateKey 对象
        byte[] privateKeyBytes = Base64.getDecoder().decode(privateKeyStr);
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);

        // 使用私钥解密数据
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] encryptedData = ...; // 待解密的数据
        byte[] decryptedData = cipher.doFinal(encryptedData);
        System.out.println(new String(decryptedData));
    }
}

请注意，上述代码中使用了 Base64 解码私钥字符串，您需要将 `...` 替换为待解密的数据。