136 lines
4.0 KiB
C++
136 lines
4.0 KiB
C++
// Copyright (c) 2012-2022 Wojciech Figat. All rights reserved.
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#include "Encryption.h"
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#include "Engine/Platform/StringUtils.h"
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namespace
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{
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const char* base64_chars =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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"abcdefghijklmnopqrstuvwxyz"
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"0123456789+/";
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bool is_base64(byte c)
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{
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return StringUtils::IsAlnum((char)c) || c == '+' || c == '/';
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}
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// @formatter:off
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const int32 B64index[256] =
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{
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 63, 62, 62, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0,
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0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 63,
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0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
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};
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// @formatter:on
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}
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void Encryption::EncryptBytes(byte* data, uint64 size)
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{
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byte offset = 71;
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for (uint64 i = 0; i < size; i++)
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{
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data[i] = (data[i] ^ (byte)i) + offset;
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offset += 13;
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}
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}
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void Encryption::DecryptBytes(byte* data, uint64 size)
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{
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byte offset = 71;
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for (uint64 i = 0; i < size; i++)
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{
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data[i] = data[i] - offset ^ (byte)i;
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offset += 13;
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}
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}
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int32 Encryption::Base64EncodeLength(int32 size)
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{
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return (size + 2) / 3 * 4;
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}
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int32 Encryption::Base64DecodeLength(const char* encoded, int32 length)
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{
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if (length == 0)
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return 0;
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const int32 pad1 = length % 4 || encoded[length - 1] == '=';
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const int32 pad2 = pad1 && (length % 4 > 2 || encoded[length - 2] != '=');
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const int32 last = (length - pad1) / 4 << 2;
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return last / 4 * 3 + pad1 + pad2;
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}
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void Encryption::Base64Encode(const byte* bytes, int32 size, Array<char>& encoded)
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{
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encoded.Resize(Base64EncodeLength(size));
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Base64Encode(bytes, size, encoded.Get());
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}
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void Encryption::Base64Encode(const byte* bytes, int32 size, char* encoded)
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{
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int32 i;
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for (i = 0; i < size - 2; i += 3)
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{
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*encoded++ = base64_chars[bytes[i] >> 2 & 0x3F];
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*encoded++ = base64_chars[(bytes[i] & 0x3) << 4 | (int32)(bytes[i + 1] & 0xF0) >> 4];
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*encoded++ = base64_chars[(bytes[i + 1] & 0xF) << 2 | (int32)(bytes[i + 2] & 0xC0) >> 6];
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*encoded++ = base64_chars[bytes[i + 2] & 0x3F];
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}
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if (i < size)
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{
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*encoded++ = base64_chars[bytes[i] >> 2 & 0x3F];
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if (i == size - 1)
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{
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*encoded++ = base64_chars[((bytes[i] & 0x3) << 4)];
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*encoded++ = '=';
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}
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else
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{
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*encoded++ = base64_chars[(bytes[i] & 0x3) << 4 | (int32)(bytes[i + 1] & 0xF0) >> 4];
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*encoded++ = base64_chars[((bytes[i + 1] & 0xF) << 2)];
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}
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*encoded = '=';
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}
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}
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void Encryption::Base64Decode(const char* encoded, int32 length, Array<byte>& output)
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{
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output.Clear();
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if (length == 0)
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return;
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output.Resize(Base64DecodeLength(encoded, length));
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Base64Decode(encoded, length, output.Get());
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}
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void Encryption::Base64Decode(const char* encoded, int32 length, byte* output)
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{
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if (length == 0)
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return;
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int32 j = 0;
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const int32 pad1 = length % 4 || encoded[length - 1] == '=', pad2 = pad1 && (length % 4 > 2 || encoded[length - 2] != '=');
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const int32 last = (length - pad1) / 4 << 2;
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byte* str = output;
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for (int32 i = 0; i < last; i += 4)
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{
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int32 n = B64index[encoded[i]] << 18 | B64index[encoded[i + 1]] << 12 | B64index[encoded[i + 2]] << 6 | B64index[encoded[i + 3]];
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str[j++] = n >> 16;
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str[j++] = n >> 8 & 0xFF;
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str[j++] = n & 0xFF;
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}
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if (pad1)
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{
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int32 n = B64index[encoded[last]] << 18 | B64index[encoded[last + 1]] << 12;
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str[j++] = n >> 16;
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if (pad2)
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{
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n |= B64index[encoded[last + 2]] << 6;
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str[j] = n >> 8 & 0xFF;
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}
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}
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}
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