Add encryption functions (xchacha20)

Changed license to GPL 3.0 because of incompatible license with opendht.
Should odhtdb stay GPL 3.0 or should opendht be replaced with libdht
so license can be changed back to MIT?

2 files changed, 31 insertions, 1 deletions

diff --git a/src/DatabaseStorage.cpp b/src/DatabaseStorage.cpp
index 2028c63..62a2e77 100644
--- a/src/DatabaseStorage.cpp
+++ b/src/DatabaseStorage.cpp
@@ -27,7 +27,7 @@ namespace odhtdb
         {
             string errMsg = "Database storage with key ";
             errMsg += key.hashedKey.toString();
-            errMsg += " not found";
+            errMsg += " not found. Storage for a key needs to be created before data can be appended to it";
             throw DatabaseStorageNotFound(errMsg);
         }
         it->second->objects.push_back({data, timestamp, creatorPublicKey});
diff --git a/src/Encryption.cpp b/src/Encryption.cpp
new file mode 100644
index 0000000..8e87a8d
--- /dev/null
+++ b/src/Encryption.cpp
@@ -0,0 +1,30 @@
+#include "../include/Encryption.hpp"
+#include <sodium/crypto_stream_xchacha20.h>
+#include <sodium/randombytes.h>
+#include <string>
+
+namespace odhtdb
+{
+    void generateEncryptionKey(EncryptionKey *output)
+    {
+        if(!output) return;
+        crypto_stream_xchacha20_keygen((unsigned char*)output);
+    }
+    
+    int encrypt(EncryptedData *output, const EncryptionKey *key, const void *data, size_t dataSize)
+    {
+        if(!output || !key) return -1;
+        if(dataSize == 0) return 0;
+        output->data.resize(dataSize);
+        randombytes_buf(output->nonce, NONCE_BYTE_SIZE);
+        return crypto_stream_xchacha20_xor((unsigned char*)&output->data[0], (const unsigned char*)data, dataSize, (const unsigned char*)output->nonce, (const unsigned char*)key);
+    }
+    
+    int decrypt(std::string *output, const EncryptionKey *key, const EncryptedData *encryptedData)
+    {
+        if(!encryptedData || !key || !output) return -1;
+        if(encryptedData->data.empty()) return 0;
+        output->resize(encryptedData->data.size());
+        return crypto_stream_xchacha20_xor((unsigned char*)&(*output)[0], (const unsigned char*)&encryptedData->data[0], encryptedData->data.size(), (const unsigned char*)encryptedData->nonce, (const unsigned char*)key);
+    }
+}