67 lines
2.2 KiB
D
67 lines
2.2 KiB
D
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module cipher_utils;
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import botan.block.block_cipher : BlockCipher;
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import std.stdio;
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public void encryptFile(string filename, string outputFilename, BlockCipher cipher, ref ubyte[] buffer) {
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assert(buffer.length == cipher.blockSize, "Buffer length must match cipher block size.");
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File fIn = File(filename, "rb");
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File fOut = File(outputFilename, "wb");
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// First, write one block containing the file's size.
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writeSizeBytes(buffer, fIn.size);
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cipher.encrypt(buffer);
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fOut.rawWrite(buffer);
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// Then write the rest of the file.
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foreach (ubyte[] chunk; fIn.byChunk(buffer)) {
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cipher.encrypt(buffer);
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fOut.rawWrite(buffer);
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}
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fIn.close();
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fOut.close();
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}
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public void decryptFile(string filename, string outputFilename, BlockCipher cipher, ref ubyte[] buffer) {
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assert(buffer.length == cipher.blockSize, "Buffer length must match cipher block size.");
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File fIn = File(filename, "rb");
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File fOut = File(outputFilename, "wb");
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// First, read one block containing the file's size.
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fIn.rawRead(buffer);
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cipher.decrypt(buffer);
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ulong size = readSizeBytes(buffer);
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ulong bytesWritten = 0;
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// Then read the rest of the file.
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foreach (ubyte[] chunk; fIn.byChunk(buffer)) {
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cipher.decrypt(buffer);
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size_t bytesToWrite = buffer.length;
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if (bytesWritten + buffer.length > size) {
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bytesToWrite = cast(size_t) (size - bytesWritten);
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}
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fOut.rawWrite(buffer[0 .. bytesToWrite]);
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bytesWritten += bytesToWrite;
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}
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fIn.close();
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fOut.close();
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}
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private void writeSizeBytes(ref ubyte[] bytes, ulong size) {
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assert(bytes.length >= 4, "Array length must be at least 4.");
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bytes[0] = size & 0xFF;
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bytes[1] = (size << 8) & 0xFF;
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bytes[2] = (size << 16) & 0xFF;
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bytes[3] = (size << 24) & 0xFF;
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if (bytes.length > 4) {
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for (size_t i = 4; i < bytes.length; i++) {
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bytes[i] = 0;
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}
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}
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}
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private ulong readSizeBytes(ref ubyte[] bytes) {
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assert(bytes.length >= 4, "Array length must be at least 4.");
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ulong size = 0;
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size += bytes[0];
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size += bytes[1] << 8;
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size += bytes[2] << 16;
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size += bytes[3] << 24;
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return size;
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}
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