增加SpecUtil，KeyUtil增加generateRSAPrivateKey重载，（issue#ID1EIK@Gitee）

CHANGELOG.md

@@ -2,7 +2,7 @@
 # 🚀Changelog
 
 -------------------------------------------------------------------------------------------------------------
-# 5.8.41(2025-10-11)
+# 5.8.41(2025-10-12)
 
 ### 🐣新特性
 * 【core   】      增加`WeakKeyValueConcurrentMap`及其关联类，同时废弃`WeakConcurrentMap`并替换（issue#4039@Github）
@@ -22,6 +22,8 @@
 * 【core   】      `LocalDateTimeUtil.parseDate`注释修正（pr#4085@Github）
 * 【core   】      `StrUtil`增加null检查处理（pr#4086@Github）
 * 【json   】      增加Record支持（pr#4096@Github）
+* 【crypto 】      增加`SpecUtil`，`KeyUtil`增加`generateRSAPrivateKey`重载，（issue#ID1EIK@Gitee）
+* 【core   】      `RandomUtil`增加`randomStringLower`方法
 
 ### 🐞Bug修复
 * 【core   】      修复`ReflectUtil`中因class和Method关联导致的缓存无法回收问题（issue#4039@Github）

hutool-core/src/main/java/cn/hutool/core/util/RandomUtil.java

@@ -588,6 +588,17 @@ public class RandomUtil {
 		return randomString(BASE_CHAR_NUMBER, length);
 	}
 
+	/**
+	 * 获得一个随机的字符串（只包含数字和小写字母）
+	 *
+	 * @param length 字符串的长度
+	 * @return 随机字符串
+	 * @since 5.8.41
+	 */
+	public static String randomStringLower(final int length) {
+		return randomString(BASE_CHAR_NUMBER_LOWER, length);
+	}
+
 	/**
 	 * 获得一个随机的字符串（只包含数字和大写字符）
 	 *

hutool-crypto/src/main/java/cn/hutool/crypto/KeyUtil.java

@@ -222,6 +222,24 @@ public class KeyUtil {
 		}
 	}
 
+	/**
+	 * 生成RSA私钥，仅用于非对称加密
+	 * 算法见：<a href="https://docs.oracle.com/javase/7/docs/technotes/guides/security/StandardNames.html#KeyFactory">...</a>
+	 *
+	 * @param key 密钥，支持XML和Base64两种格式，XML为C#生成格式，见{@link SpecUtil#xmlToRSAPrivateCrtKeySpec(String)}
+	 * @return RSA私钥 {@link PrivateKey}
+	 * @since 7.0.0
+	 */
+	public static PrivateKey generateRSAPrivateKey(String key) {
+		Assert.notBlank(key, "Key is blank!");
+		key = StrUtil.trim(key);
+		if(StrUtil.startWith(key, '<')){
+			return generateRSAPrivateKey(SpecUtil.xmlToRSAPrivateCrtKeySpec(key));
+		}
+
+		return generatePrivateKey(AsymmetricAlgorithm.RSA.getValue(), Base64.decode(key));
+	}
+
 	/**
 	 * 生成RSA私钥，仅用于非对称加密<br>
 	 * 采用PKCS#8规范，此规范定义了私钥信息语法和加密私钥语法<br>
@@ -235,6 +253,18 @@ public class KeyUtil {
 		return generatePrivateKey(AsymmetricAlgorithm.RSA.getValue(), key);
 	}
 
+	/**
+	 * 生成RSA私钥，仅用于非对称加密<br>
+	 * 算法见：<a href="https://docs.oracle.com/javase/7/docs/technotes/guides/security/StandardNames.html#KeyFactory">...</a>
+	 *
+	 * @param keySpec {@link KeySpec}
+	 * @return RSA私钥 {@link PrivateKey}
+	 * @since 5.8.41
+	 */
+	public static PrivateKey generateRSAPrivateKey(final KeySpec keySpec) {
+		return generatePrivateKey(AsymmetricAlgorithm.RSA.getValue(), keySpec);
+	}
+
 	/**
 	 * 生成私钥，仅用于非对称加密<br>
 	 * 采用PKCS#8规范，此规范定义了私钥信息语法和加密私钥语法<br>

hutool-crypto/src/main/java/cn/hutool/crypto/SpecUtil.java

@@ -0,0 +1,138 @@
+package cn.hutool.crypto;
+
+import cn.hutool.core.codec.Base64;
+import cn.hutool.core.util.RandomUtil;
+import cn.hutool.core.util.XmlUtil;
+import org.w3c.dom.Element;
+
+import javax.crypto.spec.*;
+import java.math.BigInteger;
+import java.security.InvalidKeyException;
+import java.security.spec.KeySpec;
+import java.security.spec.RSAPrivateCrtKeySpec;
+
+/**
+ * 规范相关工具类，用于生成密钥规范、参数规范等快捷方法。
+ * <ul>
+ *     <li>{@link KeySpec}: 密钥规范</li>
+ *     <li>{@link java.security.spec.AlgorithmParameterSpec}: 参数规范</li>
+ * </ul>
+ *
+ * @author Looly
+ * @since 5.8.41
+ */
+public class SpecUtil {
+
+	/**
+	 * 根据算法创建{@link KeySpec}
+	 * <ul>
+	 *     <li>DESede: {@link DESedeKeySpec}</li>
+	 *     <li>DES   : {@link DESedeKeySpec}</li>
+	 *     <li>其它  : {@link SecretKeySpec}</li>
+	 * </ul>
+	 *
+	 * @param algorithm 算法
+	 * @param key       密钥
+	 * @return {@link KeySpec}
+	 */
+	public static KeySpec createKeySpec(final String algorithm, byte[] key) {
+		try {
+			if (algorithm.startsWith("DESede")) {
+				if (null == key) {
+					key = RandomUtil.randomBytes(24);
+				}
+				// DESede兼容
+				return new DESedeKeySpec(key);
+			} else if (algorithm.startsWith("DES")) {
+				if (null == key) {
+					key = RandomUtil.randomBytes(8);
+				}
+				return new DESKeySpec(key);
+			}
+		} catch (final InvalidKeyException e) {
+			throw new CryptoException(e);
+		}
+
+		return new SecretKeySpec(key, algorithm);
+	}
+
+	/**
+	 * 创建{@link PBEKeySpec}<br>
+	 * PBE算法没有密钥的概念，密钥在其它对称加密算法中是经过算法计算得出来的，PBE算法则是使用口令替代了密钥。
+	 *
+	 * @param password 口令
+	 * @return {@link PBEKeySpec}
+	 */
+	public static PBEKeySpec createPBEKeySpec(char[] password) {
+		if (null == password) {
+			password = RandomUtil.randomStringLower(32).toCharArray();
+		}
+		return new PBEKeySpec(password);
+	}
+
+	/**
+	 * 创建{@link PBEParameterSpec}
+	 *
+	 * @param salt           加盐值
+	 * @param iterationCount 摘要次数
+	 * @return {@link PBEParameterSpec}
+	 */
+	public static PBEParameterSpec createPBEParameterSpec(final byte[] salt, final int iterationCount) {
+		return new PBEParameterSpec(salt, iterationCount);
+	}
+
+	/**
+	 * 将XML格式的密钥参数转化为{@link RSAPrivateCrtKeySpec}，XML为C#生成格式，类似于：
+	 * <pre>{@code
+	 * <RSAKeyValue>
+	 *     <Modulus>xx</Modulus>
+	 *     <Exponent>xx</Exponent>
+	 *     <P>xxxxxxxxx</P>
+	 *     <Q>xxxxxxxxx</Q>
+	 *     <DP>xxxxxxxx</DP>
+	 *     <DQ>xxxxxxxx</DQ>
+	 *     <InverseQ>xx</InverseQ>
+	 *     <D>xxxxxxxxx</D>
+	 * </RSAKeyValue>
+	 * }</pre>
+	 *
+	 * @param xml xml格式密钥字符串
+	 * @return {@link RSAPrivateCrtKeySpec}
+	 */
+	public static RSAPrivateCrtKeySpec xmlToRSAPrivateCrtKeySpec(final String xml) {
+		// 1. 解析XML
+		final Element rootElement = XmlUtil.getRootElement(XmlUtil.parseXml(xml));
+
+		// 2. 提取各个字段
+		final String modulusB64 = XmlUtil.elementText(rootElement, "Modulus");
+		final String exponentB64 = XmlUtil.elementText(rootElement, "Exponent");
+		final String pB64 = XmlUtil.elementText(rootElement, "P");
+		final String qB64 = XmlUtil.elementText(rootElement, "Q");
+		final String dpB64 = XmlUtil.elementText(rootElement, "DP");
+		final String dqB64 = XmlUtil.elementText(rootElement, "DQ");
+		final String inverseQB64 = XmlUtil.elementText(rootElement, "InverseQ");
+		final String dB64 = XmlUtil.elementText(rootElement, "D");
+
+		// 3. Base64解码
+		final byte[] modulus = Base64.decode(modulusB64);
+		final byte[] publicExponent = Base64.decode(exponentB64);
+		final byte[] privateExponent = Base64.decode(dB64);
+		final byte[] primeP = Base64.decode(pB64);
+		final byte[] primeQ = Base64.decode(qB64);
+		final byte[] primeExponentP = Base64.decode(dpB64);
+		final byte[] primeExponentQ = Base64.decode(dqB64);
+		final byte[] crtCoefficient = Base64.decode(inverseQB64);
+
+		// 4. 创建RSAPrivateCrtKeySpec
+		return new RSAPrivateCrtKeySpec(
+			new BigInteger(1, modulus),
+			new BigInteger(1, publicExponent),
+			new BigInteger(1, privateExponent),
+			new BigInteger(1, primeP),
+			new BigInteger(1, primeQ),
+			new BigInteger(1, primeExponentP),
+			new BigInteger(1, primeExponentQ),
+			new BigInteger(1, crtCoefficient)
+		);
+	}
+}

hutool-crypto/src/test/java/cn/hutool/crypto/asymmetric/IssueID1EIKTest.java

@@ -0,0 +1,40 @@
+package cn.hutool.crypto.asymmetric;
+
+import cn.hutool.core.codec.Base64;
+import cn.hutool.crypto.KeyUtil;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.security.PrivateKey;
+
+public class IssueID1EIKTest {
+
+	@Test
+	void rsaTest(){
+		// 1. Base64解码
+		String str = "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";
+		final String xml = Base64.decodeStr(str);
+
+		final PrivateKey privateKey = KeyUtil.generateRSAPrivateKey(xml);
+		RSA rsa = new RSA(privateKey, null);
+		String decrypt = rsa.decryptStr("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", KeyType.
+			PrivateKey);
+
+		String decodeStr = "cpu=178BFBFF00A50F00\r\n" +
+			"baseBoard=MP242ML1\r\n" +
+			"bios=MP242ML1\r\n" +
+			"mac=00:FF:CB:EF:28:18|00:FF:03:A2:FC:D7|C8:94:02:F8:8A:83\r\n" +
+			"cusname=123\r\n" +
+			"serviceno=12121\r\n" +
+			"kcliccount=1\r\n" +
+			"cjliccount=1\r\n" +
+			"venprintliccount=1\r\n" +
+			"beginTime=2025-10-11 14:05:10\r\n" +
+			"endTime=2026-10-11 14:05:10\r\n" +
+			"lictype=租赁\r\n" +
+			"serviceendtime=1\r\n" +
+			"validate=1\r\n" +
+			"validateunit=年\r\n";
+		Assertions.assertEquals(decodeStr, decrypt);
+	}
+}