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Update pkcs.java to work similar to python and golang code examples #21

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Update pkcs.java to work similar to python and golang code examples #21

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70 changes: 29 additions & 41 deletions digital-signature/java-example/src/main/java/com/java/example/pkcs.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2,21 +2,15 @@

import java.io.File;
import java.io.FileReader;
import java.security.KeyFactory;
import java.security.MessageDigest;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Security;
import java.security.Signature;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.MGF1ParameterSpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.PSSParameterSpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

import javax.crypto.Cipher;

import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemReader;

Expand Down Expand Up @@ -82,45 +76,39 @@ public static PrivateKey getPrivateKey(String fileName) {
return null;
}

public static boolean Verify(PublicKey publicKey, String signature, String msg) {
try {
byte[] sigBytes = Base64.getDecoder().decode(signature.getBytes());

Cipher cipher = Cipher.getInstance("RSA/None/PKCS1Padding", "BC");
cipher.init(Cipher.DECRYPT_MODE, publicKey);
public static boolean Verify(PublicKey publicKey, String signatureStr, String msg) throws NoSuchAlgorithmException, NoSuchProviderException, InvalidAlgorithmParameterException, InvalidKeyException, SignatureException {
byte[] sigBytes = Base64.getDecoder().decode(signatureStr);

byte[] decSig = cipher.doFinal(sigBytes);
ASN1InputStream aIn = new ASN1InputStream(decSig);
ASN1Sequence seq = (ASN1Sequence) aIn.readObject();
Signature signature = Signature.getInstance("RSASSA-PSS", "BC");
RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey;

MessageDigest hash = MessageDigest.getInstance("SHA-256", "BC");
hash.update(msg.getBytes());
int saltLen = rsaPublicKey.getModulus().bitLength() / 8 - 32 - 2;

ASN1OctetString sigHash = (ASN1OctetString) seq.getObjectAt(1);
return MessageDigest.isEqual(hash.digest(), sigHash.getOctets());
} catch (Exception ex) {
PSSParameterSpec spec = new PSSParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256, saltLen, 1);

}
signature.setParameter(spec);
signature.initVerify(publicKey);
signature.update(msg.getBytes(StandardCharsets.UTF_8));

return false;
return signature.verify(sigBytes);
}

public static String Sign(PrivateKey privateKey, String msg) {
try {
Signature signature = Signature.getInstance("SHA256withRSA", "BC");
signature.initSign(privateKey);
public static String Sign(PrivateKey privateKey, String msg) throws NoSuchAlgorithmException, NoSuchProviderException, InvalidAlgorithmParameterException, SignatureException, InvalidKeyException {
Signature signature = Signature.getInstance("RSASSA-PSS", "BC");

byte[] message = msg.getBytes();
signature.update(message);
java.security.interfaces.RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey;

byte[] sigBytes = signature.sign();
// Calculate dynamic salt length: modulus byte length - digest length - 2
int saltLen = rsaPrivateKey.getModulus().bitLength() / 8 - 32 - 2;

byte[] sig64 = Base64.getEncoder().encode(sigBytes);
return new String(sig64);
} catch (Exception ex) {
System.out.println(ex.toString());
}
return "";
PSSParameterSpec pssSpec = new PSSParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256, saltLen, 1);

signature.setParameter(pssSpec);
signature.initSign(rsaPrivateKey);
signature.update(msg.getBytes(StandardCharsets.UTF_8));

byte[] sigBytes = signature.sign();
return Base64.getEncoder().encodeToString(sigBytes);
}
}