分两步创建 SHA256withRSA
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【中文标题】分两步创建 SHA256withRSA【英文标题】：Create SHA256withRSA in two steps 【发布时间】：2021-12-13 09:59:00 【问题描述】：出于教育目的，我希望能够首先为字符串创建哈希，然后从该哈希创建 RSA 数字签名，以便结果与一次性使用 SHA256withRSA 时相同。通过这种方式，我想确认我完全理解当我们调用 SHA256withRSA 时实际上为我们自动完成的所有步骤。
我还有一个问题。数字签名是在 Hash 上还是在 Base64 Encoded Hash 上完成的？
下面是我当前使用的代码，这里是代码的输出，显示这两种方法产生不同的签名，这意味着我缺少 soma 手动步骤。
AUTOMATICALLY SIGN & VERIFY
SIGNATURE = Hj6a86sR2cJoQFolbxj0blk2I9CAdTdx6WOles5t/pyUyJwa9rp2/SRx2wyXWgc6GsvoZYGLUedeJ2Lklm5hYgT/TtNBATk5eChgfkJMz3NBIRPrsl7ZPG7Wvo4VmHsPpoZZ8PdRk8qY9RLou86OyIqRcX62isuV+e/0deHJ+yTZz4vqA3y+PE4yRFp96A8sKw5VlDnByn7bsxM/QOS+sQWTsETzU9s4YSRfKNq1Urn8/VDoel7n0ORjR918P+0kwE+G77bAOI70yQZorvmbgrMLSBJeVzkKzM/YECLWyrJsqdjfp86FkA9MPGB1V6rO8q8m5GhNoJOmNhC7Ek95Bw==
MANUALLY SIGN & VERIFY
HASH = lDlahWCWx2b5TYUji52uPeReSW7vbro2wXuRsPKmOdA=
SIGNATURE = gsxw7UQpqni5HyPAw8wI2pvepbrDzizkOvO0hab1+7vi4EaYJi3n4lvnkBTOU5LXQKLZGzJcug0mL2pL/PVh8lrvzZ/F9CxULLxKpayrNkvL9yEWMvcfcku9Go5EGrxSzD7VYvkwOzHvGe4GgUGD1JOjvzXBAfJRT8h/wnZi9IPA9n31/tWI2eFw17Js/gymElycp7pjrpEhUNe/IVTP9HVfRQfAxEDAPW8GY/WFdxbD3Jk05LKvpTxua4jzCX9wJh/s8aiT9OvEXh3/zt06JSEpfgf+CpkOFJupmRhsgqebPfVQEo24ctw1DnipKkL771mm30bFcm/FF1reXuOqqQ==
public class Main
//====================================================================================
// MAIN
//====================================================================================
public static void main(String[] args) throws Exception
//CREATE DATA
String dataString = "Data to be encrypted";
byte[] dataBytes = dataString.getBytes();
//CREATE KEYS
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(2048);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
//AUTOMATICALLY SIGN & VERIFY
System.out.println("\nAUTOMATICALLY SIGN & VERIFY");
byte[] automaticSignatureBytes = AutomaticHash.sign ("SHA256withRSA", privateKey, dataBytes);
//MANUALLY SIGN & VERIFY
System.out.println("\nMANUALLY SIGN & VERIFY");
byte[] manualHashBytes = ManualHash.hash ("SHA-256", dataBytes);
byte[] manualSignatureBytes = ManualHash.sign ("NONEwithRSA", privateKey, manualHashBytes);
public class AutomaticHash
//====================================================================================
// AUTOMATICALLY SIGN
//====================================================================================
public static byte[] sign(String algorithms, PrivateKey privateKey, byte[] dataBytes) throws Exception
//CREATE SIGNATURE (use Hash first)
Signature signature = Signature.getInstance(algorithms);
signature.initSign(privateKey);
signature.update(dataBytes);
byte[] signatureBytes = signature.sign();
//ENCODE SIGNATURE
byte[] signatureEncodedBytes = Base64.getEncoder().encode(signatureBytes);
String signatureEncodedString = new String(signatureEncodedBytes);
//DISPLAY ENCODED SIGNATURE
System.out.println("SIGNATURE = " + signatureEncodedString);
//RETURN SIGNATURE
return signatureBytes;
public class ManualHash
//====================================================================================
// MANUALLY HASH
//====================================================================================
public static byte[] hash(String algorithm, byte[] dataBytes) throws Exception
//CREATE HASH
MessageDigest digest = MessageDigest.getInstance(algorithm);
byte[] hashBytes = digest.digest(dataBytes);
//ENCODE HASH
byte[] hashEncoded = Base64.getEncoder().encode(hashBytes);
String hashEncodedString = new String(hashEncoded);
//DISPLAY ENCODED HASH
System.out.println("HASH = " + hashEncodedString);
//RETURN HASH
return hashBytes;
//====================================================================================
// MANUALLY SIGN
//====================================================================================
public static byte[] sign(String algorithm, PrivateKey privateKey, byte[] hashBytes) throws Exception
//SIGN HASH
Signature signature = Signature.getInstance(algorithm);
signature.initSign(privateKey);
signature.update(hashBytes);
byte[] signatureBytes = signature.sign();
//ENCODE SIGNATURE
byte[] signatureEncodedBytes = Base64.getEncoder().encode(signatureBytes);
String signatureEncodedString = new String(signatureEncodedBytes);
//DISPLAY ENCODED HASH & SIGNATURE
System.out.println("SIGNATURE = " + signatureEncodedString);
//RETURN SIGNATURE
return signatureBytes;
【问题讨论】：
对数据的哈希进行签名。您对代码有什么疑问？ 所以我必须签署 hashBytes 而不是 hashEncoded？这就是我目前正在做的事情。我已经更新了问题。代码输出显示这两种方法产生不同的签名，这意味着我缺少 soma 手动步骤。 所以我必须签署 hashBytes 而不是 hashEncoded？ 是的。关于不同的结果，请看我的回答。 【参考方案1】：SHA256withRSA 和 NoneWithRSA 使用 PKCS#1 v1.5 填充，更准确地说是 RSASSA-PKCS1-v1_5。这是一个确定性填充，即使用相同数据重复签名将产生相同的签名。详情可见RFC8017, 8.2.
当字节序列 (0x)30 31 30 0d 06 09 60 86 48 01 65 03 04 02 01 05 00 时，此填充应用 SHA256 的 DigestInfo 的 DER 编码04 20 被添加到哈希之前。
因此必须修改您的手动代码，例如如下：
public static byte[] sign(String algorithm, PrivateKey privateKey, byte[] hashBytes) throws Exception
byte[] id = new byte[] 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, (byte) 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20 ;
byte[] derDigestInfo = new byte[id.length + hashBytes.length];
System.arraycopy(id, 0, derDigestInfo, 0, id.length);
System.arraycopy(hashBytes, 0, derDigestInfo, id.length, hashBytes.length);
// SIGN HASH
Signature signature = Signature.getInstance(algorithm);
signature.initSign(privateKey);
signature.update(derDigestInfo);
byte[] signatureBytes = signature.sign();
...
通过此更改，sign() 两个方法返回相同的结果。
顺便说一句，java.util.Base64.Encoder.encodeToString()直接生成一个 Base64 编码的字符串。
此外，在编码/解码时，应始终指定字符集，例如dataString.getBytes(StandardCharsets.UTF_8) 或 new String(..., StandardCharsets.UTF_8)。否则将使用平台的默认字符集，这可能与预期的不同。
【讨论】：
你也可以为 SHA-1 做吗？ 对于 SHA-1 类似，只需使用适当的标识符（"SHA1withRSA" 和 "SHA-1"）和适当的字节序列（(0x)30 21 30 09 06 05 2b 0e 03 02 1a 05 00 04 14)，有关后者和其他摘要，请参阅 RFC8017, p.47。注意：SHA-1 不安全！【参考方案2】：
这是基于 SHA-1 和 SHA-256 注释的完整代码
import java.nio.charset.StandardCharsets;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
public class Main
//====================================================================================
// MAIN
//====================================================================================
public static void main(String[] args) throws Exception
//CREATE DATA
String dataString = "Data to be encrypted";
byte[] dataBytes = dataString.getBytes(StandardCharsets.UTF_8);
//CREATE KEYS
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(2048);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
PublicKey publicKey = keyPair.getPublic();
//SIGN
SHA1withRSA (privateKey, publicKey, dataBytes);
SHA256withRSA(privateKey, publicKey, dataBytes);
//====================================================================================
// SHA1 WITH RSA
//====================================================================================
private static void SHA1withRSA(PrivateKey privateKey, PublicKey publicKey, byte[] dataBytes) throws Exception
//LOG
System.out.println("\nSHA1 WITH RSA ==================================================================");
//AUTOMATICALLY SIGN & VERIFY
System.out.println("\nAUTOMATICALLY SIGN & VERIFY");
byte[] automaticSignatureBytes = AutomaticHash.sign ("SHA1withRSA", privateKey, dataBytes);
Boolean automaticVerified = AutomaticHash.verify("SHA1withRSA", publicKey , dataBytes, automaticSignatureBytes);
//MANUALLY SIGN & VERIFY
System.out.println("\nMANUALLY SIGN & VERIFY");
byte[] manualHashBytes = ManualHash.hash ("SHA-1", dataBytes);
byte[] manualPaddingHashBytes = ManualHash.padding("SHA-1", manualHashBytes);
byte[] manualSignatureBytes = ManualHash.sign ("NONEwithRSA", privateKey, manualPaddingHashBytes);
Boolean manualVerified = ManualHash.verify ("NONEwithRSA", publicKey , manualPaddingHashBytes, manualSignatureBytes);
//====================================================================================
// SHA256 WITH RSA
//====================================================================================
private static void SHA256withRSA(PrivateKey privateKey, PublicKey publicKey, byte[] dataBytes) throws Exception
//LOG
System.out.println("\nSHA256 WITH RSA ================================================================");
//AUTOMATICALLY SIGN & VERIFY
System.out.println("\nAUTOMATICALLY SIGN & VERIFY");
byte[] automaticSignatureBytes = AutomaticHash.sign ("SHA256withRSA", privateKey, dataBytes);
Boolean automaticVerified = AutomaticHash.verify("SHA256withRSA", publicKey , dataBytes, automaticSignatureBytes);
//MANUALLY SIGN & VERIFY
System.out.println("\nMANUALLY SIGN & VERIFY");
byte[] manualHashBytes = ManualHash.hash ("SHA-256", dataBytes);
byte[] manualPaddingHashBytes = ManualHash.padding("SHA-256", manualHashBytes);
byte[] manualSignatureBytes = ManualHash.sign ("NONEwithRSA", privateKey, manualPaddingHashBytes);
Boolean manualVerified = ManualHash.verify ("NONEwithRSA", publicKey , manualPaddingHashBytes, manualSignatureBytes);
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.util.Base64;
public class AutomaticHash
//====================================================================================
// AUTOMATICALLY SIGN
//====================================================================================
public static byte[] sign(String algorithms, PrivateKey privateKey, byte[] dataBytes) throws Exception
//CREATE SIGNATURE (use Hash first)
Signature signature = Signature.getInstance(algorithms);
signature.initSign(privateKey);
signature.update(dataBytes);
byte[] signatureBytes = signature.sign();
//DISPLAY ENCODED SIGNATURE
System.out.println("SIGNATURE = " + Base64.getEncoder().encodeToString(signatureBytes));
//RETURN SIGNATURE
return signatureBytes;
//====================================================================================
// AUTOMATICALLY VERIFY
//====================================================================================
public static Boolean verify(String algorithms, PublicKey publicKey, byte[] dataBytes, byte[] signatureBytes) throws Exception
//INITIALIZE SIGNATURE
Signature signature = Signature.getInstance(algorithms);
signature.initVerify(publicKey);
signature.update(dataBytes);
//VERIFY SIGNATURE
boolean verified = signature.verify(signatureBytes);
//DISPLAY VERIFICATION
System.out.println("VERIFIED = " + verified);
//RETURN SIGNATURE
return verified;
import java.security.MessageDigest;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.util.Base64;
public class ManualHash
//====================================================================================
// HASH
//====================================================================================
public static byte[] hash(String algorithm, byte[] dataBytes) throws Exception
//CREATE HASH
MessageDigest digest = MessageDigest.getInstance(algorithm);
byte[] hashBytes = digest.digest(dataBytes);
//DISPLAY ENCODED HASH
System.out.println("HASH = " + Base64.getEncoder().encodeToString(hashBytes));
//RETURN HASH
return hashBytes;
//====================================================================================
// PADDING
//====================================================================================
public static byte[] padding(String algorithm, byte[] hashBytes) throws Exception
//PREPARE PADDING
byte[] padding = null;
if (algorithm.equals("SHA-1" )) padding = new byte[] 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, (byte) 0x0e, 0x03, 0x02, 0x1a, 0x05, 0x00, 0x04, 0x14 ;
if (algorithm.equals("SHA-256")) padding = new byte[] 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, (byte) 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20 ;
//ADD PADDING & HASH TO RESULTING ARRAY
byte[] paddingHash = new byte[padding.length + hashBytes.length];
System.arraycopy(padding , 0, paddingHash, 0 , padding.length );
System.arraycopy(hashBytes, 0, paddingHash, padding.length, hashBytes.length);
//RETURN HASH
return paddingHash;
//====================================================================================
// SIGN
//====================================================================================
public static byte[] sign(String algorithm, PrivateKey privateKey, byte[] paddingHash) throws Exception
//SIGN PADDED HASH
Signature signature = Signature.getInstance(algorithm);
signature.initSign(privateKey);
signature.update(paddingHash);
byte[] signatureBytes = signature.sign();
//DISPLAY ENCODED HASH & SIGNATURE
System.out.println("SIGNATURE = " + Base64.getEncoder().encodeToString(signatureBytes));
//RETURN SIGNATURE
return signatureBytes;
//====================================================================================
// MANUALLY VERIFY
//====================================================================================
public static Boolean verify(String algorithm, PublicKey publicKey, byte[] hashBytes, byte[] signatureBytes) throws Exception
//INITIALIZE SIGNATURE
Signature signature = Signature.getInstance(algorithm);
signature.initVerify(publicKey);
signature.update(hashBytes);
//VERIFY SIGNATURE
boolean verified = signature.verify(signatureBytes);
//DISPLAY VERIFICATION
System.out.println("VERIFIED = " + verified);
//RETURN SIGNATURE
return verified;
结果
SHA1 WITH RSA ==================================================================
AUTOMATICALLY SIGN & VERIFY
SIGNATURE = bGLX8elMdZeyDmT1YCh86Uz5kH9P69NpAqYYNn11ybyYp2cqLUSyqTEolhv4QgEAnSoyGQH9McjEMqhDL+u8Kp68nDRmt2ScFtNN17i0F7+65XO2PHqQtpfOsb2tUoG4Q+SmoBWSiXJliIQTRjYeblgLteY74SJreDlN7AAEYmFpi9oVbptwCj0OnZMlz5EdffX66Yy47qxYSF3O3Wuea1mCY/lG52qHwTFFJ+//N+X/5wFX4UDpzA+BMoWynE7FKzzfkQOGl9LazhFCTH46i30UHXmNGlbrjpApRtZKL9LnZUNPbLJTVKtCDZFMEdocT/a9NBeclZPtu/LBj3l+Iw==
VERIFIED = true
MANUALLY SIGN & VERIFY
HASH = +AayjWUd2pEmeoC49PlJj2mMdG4=
SIGNATURE = bGLX8elMdZeyDmT1YCh86Uz5kH9P69NpAqYYNn11ybyYp2cqLUSyqTEolhv4QgEAnSoyGQH9McjEMqhDL+u8Kp68nDRmt2ScFtNN17i0F7+65XO2PHqQtpfOsb2tUoG4Q+SmoBWSiXJliIQTRjYeblgLteY74SJreDlN7AAEYmFpi9oVbptwCj0OnZMlz5EdffX66Yy47qxYSF3O3Wuea1mCY/lG52qHwTFFJ+//N+X/5wFX4UDpzA+BMoWynE7FKzzfkQOGl9LazhFCTH46i30UHXmNGlbrjpApRtZKL9LnZUNPbLJTVKtCDZFMEdocT/a9NBeclZPtu/LBj3l+Iw==
VERIFIED = true
SHA256 WITH RSA ================================================================
AUTOMATICALLY SIGN & VERIFY
SIGNATURE = M7bqVsCdlQnjCBBupuOmCJSzhuZ4C2K1VsNcJUXpdKBt17jy3TbFKcaYQ47Lsj0x/xqHFK3OTFxxZRjZyywqk25ovyzTfCkwHoEYWE2TiApEkf92pTcVn86YkFhDQCSJWboJu75NAEtDxkiJelUut3DmHp0Pu91U17cKC6JxUSIHlTQAxbNHhUfkx0YdE6sTvzK2lG/XJcZdA/Nx6qia9548EsBoi71vY1GlsSn7pEf5pg5yCJF5fAufD9hRSPI5OX2TKtj3hYXMr8UXQ6VaDBf4PiJjQ8MNg+q4cXtr+BpK1uHtxm0BuRHlcM4eBkTyuia93Xc88Ojwsma2tlCrwg==
VERIFIED = true
MANUALLY SIGN & VERIFY
HASH = lDlahWCWx2b5TYUji52uPeReSW7vbro2wXuRsPKmOdA=
SIGNATURE = M7bqVsCdlQnjCBBupuOmCJSzhuZ4C2K1VsNcJUXpdKBt17jy3TbFKcaYQ47Lsj0x/xqHFK3OTFxxZRjZyywqk25ovyzTfCkwHoEYWE2TiApEkf92pTcVn86YkFhDQCSJWboJu75NAEtDxkiJelUut3DmHp0Pu91U17cKC6JxUSIHlTQAxbNHhUfkx0YdE6sTvzK2lG/XJcZdA/Nx6qia9548EsBoi71vY1GlsSn7pEf5pg5yCJF5fAufD9hRSPI5OX2TKtj3hYXMr8UXQ6VaDBf4PiJjQ8MNg+q4cXtr+BpK1uHtxm0BuRHlcM4eBkTyuia93Xc88Ojwsma2tlCrwg==
VERIFIED = true
【讨论】：
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