refacturing: extract crypto code from asap protocol.

thsc42 · thsc42 · commit 97acc58933d3 · 2020-09-09T07:55:45.000+02:00
diff --git a/src/net/sharksystem/asap/protocol/ASAPCryptoMessage.java b/src/net/sharksystem/asap/protocol/ASAPCryptoMessage.java
@@ -6,22 +6,18 @@
 import net.sharksystem.crypto.ASAPCryptoAlgorithms;
 import net.sharksystem.utils.Serialization;
 
-import javax.crypto.*;
-import javax.crypto.spec.SecretKeySpec;
 import java.io.*;
-import java.security.*;
 
 class ASAPCryptoMessage {
     private boolean encrypted;
     private boolean sign;
-    private Signature signature;
     private CharSequence recipient;
     private BasisCryptoParameters basisCryptoParameters;
     private byte cmd;
 
-    private OutputStream effectivOS;
+    private OutputStream effectiveOS;
     private OutputStream realOS;
-    private ByteArrayOutputStream asapMessageOS;
+    private ByteArrayOutputStream outputStreamCopy;
     private InputStreamCopy inputStreamCopy;
     private ASAPCryptoAlgorithms.EncryptedMessagePackage encryptedMessagePackage;
 
@@ -36,7 +32,7 @@ class ASAPCryptoMessage {
 
         this.cmd = cmd;
         this.realOS = os;
-        this.effectivOS = os; // still this one
+        this.effectiveOS = os; // still this one
         this.basisCryptoParameters = basisCryptoParameters;
         this.recipient = recipient;
         this.encrypted = encrypted;
@@ -47,7 +43,7 @@ class ASAPCryptoMessage {
             if(basisCryptoParameters == null) {
                 throw new ASAPSecurityException("cannot encrypt or sign without cryptp parameters / key store");
             }
-            this.setupTempMessageStorage();
+            this.setupCopyOutputStream();
         }
 
         if(encrypted) {
@@ -66,11 +62,11 @@ class ASAPCryptoMessage {
         }
     }
 
-    private void setupTempMessageStorage() {
-        if(this.asapMessageOS == null) {
-            this.asapMessageOS = new ByteArrayOutputStream();
+    private void setupCopyOutputStream() {
+        if(this.outputStreamCopy == null) {
+            this.outputStreamCopy = new ByteArrayOutputStream();
             // pud will make a detour
-            this.effectivOS = this.asapMessageOS;
+            this.effectiveOS = this.outputStreamCopy;
         }
     }
 
@@ -79,27 +75,23 @@ public void sendCmd() throws IOException {
         PDU_Impl.sendCmd(this.cmd, this.realOS);
     }
 
-    byte getCMD() {
-        return this.cmd;
-    }
-
     public OutputStream getOutputStream() {
-        return this.effectivOS;
+        return this.effectiveOS;
     }
 
     public void finish() throws ASAPSecurityException {
         if(this.sign) {
             try {
                 // get message as bytes
-                byte[] asapMessageAsBytes = this.asapMessageOS.toByteArray();
+                byte[] asapMessageAsBytes = this.outputStreamCopy.toByteArray();
                 // produce signature
                 byte[] signatureBytes = ASAPCryptoAlgorithms.sign(asapMessageAsBytes, this.basisCryptoParameters);
 
                 if(this.encrypted) {
-                    // have to store it - anything will be encrypted
-                    Serialization.writeByteArray(signatureBytes, this.asapMessageOS);
+                    // have to store it - message and signature will be encrypted
+                    Serialization.writeByteArray(signatureBytes, this.outputStreamCopy);
                 } else {
-                    // can write anything now
+                    // no encryption planned - write clear to stream
                     this.realOS.write(asapMessageAsBytes);
                     Serialization.writeByteArray(signatureBytes, this.realOS);
                 }
@@ -110,7 +102,7 @@ public void finish() throws ASAPSecurityException {
 
         if(this.encrypted) {
             // get maybe signed asap message
-            byte[] asapMessageAsBytes = this.asapMessageOS.toByteArray();
+            byte[] asapMessageAsBytes = this.outputStreamCopy.toByteArray();
 
             ASAPCryptoAlgorithms.writeEncryptedMessagePackage(
                     asapMessageAsBytes, this.recipient, this.basisCryptoParameters, this.realOS);
@@ -147,7 +139,7 @@ byte[] getCopy() {
         }
     }
 
-    public InputStream setupCopyStream(int priorInt, InputStream is)
+    public InputStream setupCopyInputStream(int priorInt, InputStream is)
             throws IOException {
 
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -163,21 +155,13 @@ public InputStream setupCopyStream(int priorInt, InputStream is)
 
     public boolean verify(String sender, InputStream is) throws IOException, ASAPException {
         // try to get senders' public key
-        PublicKey publicKey = this.basisCryptoParameters.getPublicKey(sender);
-        if(publicKey == null) return false;
-
-        try {
-            this.signature = Signature.getInstance(this.basisCryptoParameters.getRSASigningAlgorithm());
-            this.signature.initVerify(publicKey);
-            // get data which are to be verified
-            byte[] signedData = this.inputStreamCopy.getCopy();
-            this.signature.update(signedData);
-            byte[] signatureBytes = Serialization.readByteArray(is);
-            boolean wasVerified = this.signature.verify(signatureBytes);
-            return wasVerified;
-        } catch (NoSuchAlgorithmException | SignatureException | InvalidKeyException e) {
-            throw new ASAPSecurityException(this.getLogStart(), e);
-        }
+        byte[] signedData = this.inputStreamCopy.getCopy();
+        byte[] signatureBytes = Serialization.readByteArray(is);
+        // debug break
+        boolean wasVerified =
+                ASAPCryptoAlgorithms.verify(signedData, signatureBytes, sender, this.basisCryptoParameters);
+
+        return wasVerified;
     }
 
     ////////////////////////////////// decrypt
@@ -194,19 +178,8 @@ public boolean verify(String sender, InputStream is) throws IOException, ASAPExc
      * @throws ASAPException
      */
     public boolean initDecryption(byte cmd, InputStream is) throws IOException, ASAPException {
-        // make a copy of read data
-        InputStream copyStream = this.setupCopyStream(cmd, is);
-
-        /*
-        // read recipient
-        this.recipient = Serialization.readCharSequenceParameter(copyStream);
-
-        // read encrypted symmetric key
-        this.encryptedSymmetricKey = Serialization.readByteArray(copyStream);
-
-        // read content
-        this.encryptedContent = Serialization.readByteArray(copyStream);
-         */
+        // make a copy of encrypted message - it is redundant. Same data in encryptedMessagePackage
+        InputStream copyStream = this.setupCopyInputStream(cmd, is);
 
         this.encryptedMessagePackage =
                 ASAPCryptoAlgorithms.parseEncryptedMessagePackage(copyStream);
@@ -216,8 +189,6 @@ public boolean initDecryption(byte cmd, InputStream is) throws IOException, ASAP
             return false;
         }
 
-        // read anything - are we recipient?
-//        if(this.basisCryptoParameters.isOwner(this.recipient)) {
         if(this.basisCryptoParameters.isOwner(this.encryptedMessagePackage.getRecipient())) {
             return true;
         }
@@ -234,38 +205,13 @@ byte[] getEncryptedMessage() throws ASAPSecurityException {
         return this.inputStreamCopy.getCopy();
     }
 
-    public InputStream doDecryption(InputStream is) throws ASAPSecurityException {
-        return this.doDecryption(is, this.basisCryptoParameters.getPrivateKey());
-    }
-
-    // parameter private key is usually not an option. Good entry for testing / debugging, though
-    public InputStream doDecryption(InputStream is, PrivateKey privateKey) throws ASAPSecurityException {
+    public InputStream doDecryption() throws ASAPSecurityException {
         if(this.encryptedMessagePackage == null) {
             throw new ASAPSecurityException("forgot to initialize decryption? There are no data");
         }
-        /*
-        // decrypt encoded symmetric key
-        this.cipher = Cipher.getInstance(basisCryptoParameters.getRSAEncryptionAlgorithm());
-        this.cipher.init(Cipher.DECRYPT_MODE, privateKey);
-
-        // read encryptedKey in initDecryption
-        byte[] encodedSymmetricKey = this.cipher.doFinal(this.encryptedSymmetricKey);
-         */
-
-        byte[] encodedSymmetricKey = ASAPCryptoAlgorithms.decryptAsymmetric(
-                this.encryptedMessagePackage.getEncryptedSymmetricKey(),
-                this.basisCryptoParameters);
-
-        // create symmetric key object
-        SecretKey symmetricKey =
-                ASAPCryptoAlgorithms.createSymmetricKey(encodedSymmetricKey, this.basisCryptoParameters);
-
 
-        // decrypt content
-        byte[] decryptedBytes = ASAPCryptoAlgorithms.decryptSymmetric(
-                this.encryptedMessagePackage.getEncryptedContent(),
-                symmetricKey,
-                this.basisCryptoParameters);
+        byte[] decryptedBytes =
+                ASAPCryptoAlgorithms.decryptPackage(this.encryptedMessagePackage, this.basisCryptoParameters);
 
         return new ByteArrayInputStream(decryptedBytes);
     }
diff --git a/src/net/sharksystem/asap/protocol/ASAP_Modem_Impl.java b/src/net/sharksystem/asap/protocol/ASAP_Modem_Impl.java
@@ -180,7 +180,7 @@ public ASAP_PDU_1_0 readPDU(InputStream is) throws IOException, ASAPException {
             boolean ownerIsRecipient = cryptoMessage.initDecryption(cmd, is);
             if(ownerIsRecipient) {
                 // peer is recipient - decrypt and go ahead
-                InputStream decryptedIS = cryptoMessage.doDecryption(is);
+                InputStream decryptedIS = cryptoMessage.doDecryption();
                 is = decryptedIS;
             } else {
                 // we cannot decrypt this message - we are not recipient - but we keep and redistribute
@@ -203,7 +203,7 @@ public ASAP_PDU_1_0 readPDU(InputStream is) throws IOException, ASAPException {
         ASAPCryptoMessage verifyCryptoMessage = null;
         if(PDU_Impl.flagSet(PDU_Impl.SIGNED_TO_BIT_POSITION, flagsInt)) {
             verifyCryptoMessage = new ASAPCryptoMessage(this.signAndEncryptionKeyStorage);
-            is = verifyCryptoMessage.setupCopyStream(flagsInt, is);
+            is = verifyCryptoMessage.setupCopyInputStream(flagsInt, is);
         }
 
         PDU_Impl pdu = null;
diff --git a/src/net/sharksystem/crypto/ASAPCryptoAlgorithms.java b/src/net/sharksystem/crypto/ASAPCryptoAlgorithms.java
@@ -72,6 +72,21 @@ public static SecretKey createSymmetricKey(byte[] encodedSymmetricKey,
         return new SecretKeySpec(encodedSymmetricKey, basisCryptoParameters.getSymmetricKeyType());
     }
 
+    public static byte[] decryptPackage(EncryptedMessagePackage encryptedMessagePackage,
+                            BasisCryptoParameters basisCryptoParameters) throws ASAPSecurityException {
+
+        byte[] encodedSymmetricKey = decryptAsymmetric(
+                encryptedMessagePackage.getEncryptedSymmetricKey(),
+                basisCryptoParameters);
+
+        // create symmetric key object
+        SecretKey symmetricKey = createSymmetricKey(encodedSymmetricKey, basisCryptoParameters);
+
+
+        // decrypt content
+        return decryptSymmetric(encryptedMessagePackage.getEncryptedContent(), symmetricKey, basisCryptoParameters);
+    }
+
     public interface EncryptedMessagePackage {
         CharSequence getRecipient();
         byte[] getEncryptedSymmetricKey();
@@ -142,7 +157,8 @@ public static byte[] decryptSymmetric(byte[] encryptedContent, SecretKey symmetr
         }
     }
 
-    public static byte[] decryptAsymmetric(byte[] encryptedBytes, BasisCryptoParameters basisCryptoParameters) throws ASAPSecurityException {
+    public static byte[] decryptAsymmetric(byte[] encryptedBytes, BasisCryptoParameters basisCryptoParameters)
+            throws ASAPSecurityException {
         try {
             Cipher cipher = Cipher.getInstance(basisCryptoParameters.getRSAEncryptionAlgorithm());
             cipher.init(Cipher.DECRYPT_MODE, basisCryptoParameters.getPrivateKey());
@@ -166,5 +182,19 @@ public static byte[] sign(byte[] bytes2Sign, BasisCryptoParameters basisCryptoPa
         }
     }
 
-    public static byte[] verify() {return null;}
+    public static boolean verify(byte[] signedData, byte[] signatureBytes, String sender,
+                        BasisCryptoParameters basisCryptoParameters) throws ASAPSecurityException {
+
+        PublicKey publicKey = basisCryptoParameters.getPublicKey(sender);
+        if(publicKey == null) return false;
+
+        try {
+            Signature signature = Signature.getInstance(basisCryptoParameters.getRSASigningAlgorithm());
+            signature.initVerify(publicKey); // init with private key
+            signature.update(signedData); // feed with signed data
+            return signature.verify(signatureBytes); // check against signature
+        } catch (NoSuchAlgorithmException | SignatureException | InvalidKeyException e) {
+            throw new ASAPSecurityException("problems when verifying", e);
+        }
+    }
 }
