SymmetricCipher: Support CTR mode

Includes AES-256-CTR non-stream tests

4 files changed, 53 insertions, 1 deletions

diff --git a/src/crypto/SymmetricCipher.h b/src/crypto/SymmetricCipher.h
index b85c58b7c..4f1d50c12 100644
--- a/src/crypto/SymmetricCipher.h
+++ b/src/crypto/SymmetricCipher.h
@@ -38,6 +38,7 @@ public:
     enum Mode
     {
         Cbc,
+        Ctr,
         Ecb,
         Stream
     };
diff --git a/src/crypto/SymmetricCipherGcrypt.cpp b/src/crypto/SymmetricCipherGcrypt.cpp
index e600a7edb..c88dbd8c2 100644
--- a/src/crypto/SymmetricCipherGcrypt.cpp
+++ b/src/crypto/SymmetricCipherGcrypt.cpp
@@ -62,6 +62,9 @@ int SymmetricCipherGcrypt::gcryptMode(SymmetricCipher::Mode mode)
     case SymmetricCipher::Cbc:
         return GCRY_CIPHER_MODE_CBC;
 
+    case SymmetricCipher::Ctr:
+        return GCRY_CIPHER_MODE_CTR;
+
     case SymmetricCipher::Stream:
         return GCRY_CIPHER_MODE_STREAM;
 
@@ -119,7 +122,13 @@ bool SymmetricCipherGcrypt::setKey(const QByteArray& key)
 bool SymmetricCipherGcrypt::setIv(const QByteArray& iv)
 {
     m_iv = iv;
-    gcry_error_t error = gcry_cipher_setiv(m_ctx, m_iv.constData(), m_iv.size());
+    gcry_error_t error;
+
+    if (m_mode == GCRY_CIPHER_MODE_CTR) {
+        error = gcry_cipher_setctr(m_ctx, m_iv.constData(), m_iv.size());
+    } else {
+        error = gcry_cipher_setiv(m_ctx, m_iv.constData(), m_iv.size());
+    }
 
     if (error != 0) {
         setErrorString(error);
diff --git a/tests/TestSymmetricCipher.cpp b/tests/TestSymmetricCipher.cpp
index 4f78693d6..74f720a7f 100644
--- a/tests/TestSymmetricCipher.cpp
+++ b/tests/TestSymmetricCipher.cpp
@@ -124,6 +124,46 @@ void TestSymmetricCipher::testAes256CbcDecryption()
              plainText);
 }
 
+void TestSymmetricCipher::testAes256CtrEncryption()
+{
+    // http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf
+
+    QByteArray key = QByteArray::fromHex("603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4");
+    QByteArray ctr = QByteArray::fromHex("f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff");
+    QByteArray plainText = QByteArray::fromHex("6bc1bee22e409f96e93d7e117393172a");
+    plainText.append(QByteArray::fromHex("ae2d8a571e03ac9c9eb76fac45af8e51"));
+    QByteArray cipherText = QByteArray::fromHex("601ec313775789a5b7a7f504bbf3d228");
+    cipherText.append(QByteArray::fromHex("f443e3ca4d62b59aca84e990cacaf5c5"));
+    bool ok;
+
+    SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Ctr, SymmetricCipher::Encrypt);
+    QVERIFY(cipher.init(key, ctr));
+    QCOMPARE(cipher.blockSize(), 16);
+
+    QCOMPARE(cipher.process(plainText, &ok),
+             cipherText);
+    QVERIFY(ok);
+}
+
+void TestSymmetricCipher::testAes256CtrDecryption()
+{
+    QByteArray key = QByteArray::fromHex("603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4");
+    QByteArray ctr = QByteArray::fromHex("f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff");
+    QByteArray cipherText = QByteArray::fromHex("601ec313775789a5b7a7f504bbf3d228");
+    cipherText.append(QByteArray::fromHex("f443e3ca4d62b59aca84e990cacaf5c5"));
+    QByteArray plainText = QByteArray::fromHex("6bc1bee22e409f96e93d7e117393172a");
+    plainText.append(QByteArray::fromHex("ae2d8a571e03ac9c9eb76fac45af8e51"));
+    bool ok;
+
+    SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Ctr, SymmetricCipher::Decrypt);
+    QVERIFY(cipher.init(key, ctr));
+    QCOMPARE(cipher.blockSize(), 16);
+
+    QCOMPARE(cipher.process(cipherText, &ok),
+             plainText);
+    QVERIFY(ok);
+}
+
 void TestSymmetricCipher::testTwofish256CbcEncryption()
 {
     // NIST MCT Known-Answer Tests (cbc_e_m.txt)
diff --git a/tests/TestSymmetricCipher.h b/tests/TestSymmetricCipher.h
index 009989500..cad13841a 100644
--- a/tests/TestSymmetricCipher.h
+++ b/tests/TestSymmetricCipher.h
@@ -29,6 +29,8 @@ private slots:
     void initTestCase();
     void testAes256CbcEncryption();
     void testAes256CbcDecryption();
+    void testAes256CtrEncryption();
+    void testAes256CtrDecryption();
     void testTwofish256CbcEncryption();
     void testTwofish256CbcDecryption();
     void testSalsa20();