Crypto: Stub out EdDSA blinding (proposal 123)

core/java/src/net/i2p/crypto/Blinding.java

@@ -0,0 +1,106 @@
+package net.i2p.crypto;
+
+import java.security.GeneralSecurityException;
+
+import net.i2p.crypto.eddsa.EdDSABlinding;
+import net.i2p.crypto.eddsa.EdDSAPrivateKey;
+import net.i2p.crypto.eddsa.EdDSAPublicKey;
+import net.i2p.data.Hash;
+import net.i2p.data.SigningPrivateKey;
+import net.i2p.data.SigningPublicKey;
+import net.i2p.data.SimpleDataStructure;
+
+
+/**
+ * Utilities for Blinding EdDSA keys.
+ * PRELIMINARY - Subject to change - see proposal 123
+ *
+ * @since 0.9.38
+ */
+public final class Blinding {
+
+    private static final SigType TYPE = SigType.EdDSA_SHA512_Ed25519;
+
+    private Blinding() {}
+
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519.
+     *
+     *  @param key must be SigType EdDSA_SHA512_Ed25519
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     */
+    public static SigningPublicKey blind(SigningPublicKey key, SimpleDataStructure h) {
+        if (key.getType() != TYPE)
+            throw new UnsupportedOperationException();
+        if (h.length() != key.length())
+            throw new IllegalArgumentException();
+        try {
+            EdDSAPublicKey jk = SigUtil.toJavaEdDSAKey(key);
+            EdDSAPublicKey bjk = EdDSABlinding.blind(jk, h.getData());
+            return SigUtil.fromJavaKey(bjk, TYPE);
+        } catch (GeneralSecurityException gse) {
+            throw new IllegalArgumentException(gse);
+        }
+    }
+
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519.
+     *
+     *  @param key must be SigType EdDSA_SHA512_Ed25519
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     */
+    public static SigningPrivateKey blind(SigningPrivateKey key, SimpleDataStructure h) {
+        if (key.getType() != TYPE)
+            throw new UnsupportedOperationException();
+        if (h.length() != key.length())
+            throw new IllegalArgumentException();
+        try {
+            EdDSAPrivateKey jk = SigUtil.toJavaEdDSAKey(key);
+            EdDSAPrivateKey bjk = EdDSABlinding.blind(jk, h.getData());
+            return SigUtil.fromJavaKey(bjk, TYPE);
+        } catch (GeneralSecurityException gse) {
+            throw new IllegalArgumentException(gse);
+        }
+    }
+
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519.
+     *
+     *  @param key must be SigType EdDSA_SHA512_Ed25519
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     */
+    public static SigningPrivateKey unblind(SigningPrivateKey key, SimpleDataStructure h) {
+        if (key.getType() != TYPE)
+            throw new UnsupportedOperationException();
+        if (h.length() != key.length())
+            throw new IllegalArgumentException();
+        try {
+            EdDSAPrivateKey bjk = SigUtil.toJavaEdDSAKey(key);
+            EdDSAPrivateKey jk = EdDSABlinding.unblind(bjk, h.getData());
+            return SigUtil.fromJavaKey(jk, TYPE);
+        } catch (GeneralSecurityException gse) {
+            throw new IllegalArgumentException(gse);
+        }
+    }
+/******
+    public static void main(String args[]) throws Exception {
+        SimpleDataStructure[] keys = KeyGenerator.getInstance().generateSigningKeys(TYPE);
+        SigningPublicKey pub = (SigningPublicKey) keys[0];
+        SigningPrivateKey priv = (SigningPrivateKey) keys[1];
+        byte[] b = new byte[32];
+        net.i2p.I2PAppContext.getGlobalContext().random().nextBytes(b);
+        Hash h = new Hash(b);
+        SigningPublicKey bpub = blind(pub, h);
+        SigningPrivateKey bpriv = blind(priv, h);
+        SigningPublicKey bpub2 = bpriv.toPublic();
+        boolean ok = bpub2.equals(bpub);
+        System.out.println("Blinding test passed?   " + ok);
+        SigningPrivateKey priv2 = unblind(bpriv, h);
+        ok = priv2.equals(priv);
+        System.out.println("Unblinding test passed? " + ok);
+    }
+******/
+}

core/java/src/net/i2p/crypto/eddsa/EdDSABlinding.java

@@ -0,0 +1,48 @@
+package net.i2p.crypto.eddsa;
+
+/**
+ * Utilities for Blinding EdDSA keys.
+ * PRELIMINARY - Subject to change - see proposal 123
+ *
+ * @since 0.9.38
+ */
+public final class EdDSABlinding {
+
+    private EdDSABlinding() {}
+
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519.
+     *
+     *  @param key must be SigType EdDSA_SHA512_Ed25519
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     */
+    public static EdDSAPublicKey blind(EdDSAPublicKey key, byte[] h) {
+        // TODO, test only
+        return key;
+    }
+
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519.
+     *
+     *  @param key must be SigType EdDSA_SHA512_Ed25519
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     */
+    public static EdDSAPrivateKey blind(EdDSAPrivateKey key, byte[] h) {
+        // TODO, test only
+        return key;
+    }
+
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519.
+     *
+     *  @param key must be SigType EdDSA_SHA512_Ed25519
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     */
+    public static EdDSAPrivateKey unblind(EdDSAPrivateKey key, byte[] h) {
+        // TODO, test only
+        return key;
+    }
+}

core/java/src/net/i2p/data/SigningPrivateKey.java

@@ -11,6 +11,7 @@ package net.i2p.data;
 
 import java.util.Arrays;
 
+import net.i2p.crypto.Blinding;
 import net.i2p.crypto.KeyGenerator;
 import net.i2p.crypto.SigType;
 
@@ -88,6 +89,17 @@ public class SigningPrivateKey extends SimpleDataStructure {
         return KeyGenerator.getSigningPublicKey(this);
     }
 
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519
+     *
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     *  @since 0.9.38
+     */
+    public SigningPrivateKey blind(SimpleDataStructure h) {
+        return Blinding.blind(this, h);
+    }
+
     /**
      *  @since 0.9.8
      */

core/java/src/net/i2p/data/SigningPublicKey.java

@@ -14,6 +14,7 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
 
+import net.i2p.crypto.Blinding;
 import net.i2p.crypto.SigType;
 
 /**
@@ -196,6 +197,17 @@ public class SigningPublicKey extends SimpleDataStructure {
             out.write(_data, 0, KEYSIZE_BYTES);
     }
 
+    /**
+     *  Only for SigType EdDSA_SHA512_Ed25519
+     *
+     *  @param h hash of secret data, same length as this key
+     *  @throws UnsupportedOperationException unless supported
+     *  @since 0.9.38
+     */
+    public SigningPublicKey blind(SimpleDataStructure h) {
+        return Blinding.blind(this, h);
+    }
+
     /**
      *  @since 0.9.8
      */