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authorAqua-sama <aqua@iserlohn-fortress.net>2020-11-08 12:13:01 +0200
committerAqua-sama <aqua@iserlohn-fortress.net>2020-11-08 12:13:01 +0200
commit6d89ab37754462928b28ad85714af316c83f43cb (patch)
tree9231ffc8b29f3d6c256ad7a074e524e58fa96b39
parentReplace P and S C-arrays with std::array (diff)
downloadblowfish-6d89ab37754462928b28ad85714af316c83f43cb.tar.xz
Add compile-time key length check
-rw-r--r--blowfish.hpp57
-rw-r--r--blowfish_init.hpp14
-rw-r--r--main.cpp2
3 files changed, 43 insertions, 30 deletions
diff --git a/blowfish.hpp b/blowfish.hpp
index 9a6e0fe..3637335 100644
--- a/blowfish.hpp
+++ b/blowfish.hpp
@@ -5,32 +5,39 @@
#include "blowfish_init.hpp"
#include <algorithm>
-class Blowfish {
-public:
- struct Block {
- constexpr Block(uint64_t x) {
- L = x >> 32;
- R = x & 0xffffffff;
- }
- constexpr Block(uint32_t l, uint32_t r) : L(l), R(r) {}
+namespace Blowfish {
+template <std::size_t sz> concept is_valid_key_length = (sz < KEYLEN);
- constexpr operator uint64_t() const {
- return (static_cast<uint64_t>(L) << 32) + R;
- }
- uint32_t L;
- uint32_t R;
- };
+struct Block {
+ constexpr Block(uint64_t x) {
+ static_assert(sizeof(Block) == sizeof(uint64_t));
+ L = x >> 32;
+ R = x & 0xffffffff;
+ }
+ constexpr Block(uint32_t l, uint32_t r) : L(l), R(r) {
+ static_assert(sizeof(Block) == sizeof(uint64_t));
+ }
- constexpr Blowfish(const uint8_t key[], size_t keylen) {
- for (size_t i = 0; i < BOXES; ++i) {
+ constexpr operator uint64_t() const {
+ return (static_cast<uint64_t>(L) << 32) + R;
+ }
+ uint32_t L;
+ uint32_t R;
+};
+
+template <std::size_t keylen>
+requires is_valid_key_length<keylen> class Context {
+public:
+ constexpr Context(const std::array<uint8_t, keylen> &key) {
+ for (std::size_t i = 0; i < BOXES; ++i) {
std::copy(S_INIT[i].begin(), S_INIT[i].end(), S[i].begin());
}
//
- size_t k = 0;
- for (size_t i = 0; i < SUBKEYS; ++i) {
+ std::size_t k = 0;
+ for (std::size_t i = 0; i < SUBKEYS; ++i) {
uint32_t qk = 0;
- for (size_t j = 0; j < 4; ++j) {
+ for (std::size_t j = 0; j < 4; ++j) {
qk = (qk << 8) | key[k];
++k;
if (k >= keylen) {
@@ -42,13 +49,13 @@ public:
Block x(0, 0);
- for (size_t i = 0; i < SUBKEYS; i += 2) {
+ for (std::size_t i = 0; i < SUBKEYS; i += 2) {
x = encrypt(x);
P[i] = x.L;
P[i + 1] = x.R;
}
- for (size_t i = 0; i < BOXES; ++i) {
- for (size_t j = 0; j < ENTRIES; j += 2) {
+ for (std::size_t i = 0; i < BOXES; ++i) {
+ for (std::size_t j = 0; j < ENTRIES; j += 2) {
x = encrypt(x);
S[i][j] = x.L;
S[i][j + 1] = x.R;
@@ -58,7 +65,7 @@ public:
constexpr Block encrypt(const Block &x) const {
Block y(x);
- for (size_t i = 0; i < ROUNDS; ++i) {
+ for (std::size_t i = 0; i < ROUNDS; ++i) {
y.L = y.L ^ P[i];
y.R = F(y.L) ^ y.R;
std::swap(y.L, y.R);
@@ -72,7 +79,7 @@ public:
constexpr Block decrypt(const Block &x) const {
Block y(x);
- for (size_t i = ROUNDS + 1; i > 1; --i) {
+ for (std::size_t i = ROUNDS + 1; i > 1; --i) {
y.L = y.L ^ P[i];
y.R = F(y.L) ^ y.R;
std::swap(y.L, y.R);
@@ -99,3 +106,5 @@ private:
std::array<uint32_t, SUBKEYS> P;
std::array<std::array<uint32_t, ENTRIES>, BOXES> S;
};
+
+} // namespace Blowfish
diff --git a/blowfish_init.hpp b/blowfish_init.hpp
index 9d2366d..2d7bf6c 100644
--- a/blowfish_init.hpp
+++ b/blowfish_init.hpp
@@ -1,12 +1,14 @@
#pragma once
#include <array>
-#include <cstddef>
#include <cstdint>
-constexpr size_t ROUNDS = 16;
-constexpr size_t SUBKEYS = ROUNDS + 2;
-constexpr size_t BOXES = 4;
-constexpr size_t ENTRIES = 256;
+namespace Blowfish {
+
+constexpr std::size_t KEYLEN = 448 / sizeof(uint8_t);
+constexpr std::size_t ROUNDS = 16;
+constexpr std::size_t SUBKEYS = ROUNDS + 2;
+constexpr std::size_t BOXES = 4;
+constexpr std::size_t ENTRIES = 256;
constexpr std::array<uint32_t, SUBKEYS> P_INIT{
0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344, 0xa4093822, 0x299f31d0,
@@ -191,3 +193,5 @@ constexpr std::array<std::array<uint32_t, ENTRIES>, BOXES> S_INIT{
0x85cbfe4e, 0x8ae88dd8, 0x7aaaf9b0, 0x4cf9aa7e, 0x1948c25c, 0x02fb8a8c,
0x01c36ae4, 0xd6ebe1f9, 0x90d4f869, 0xa65cdea0, 0x3f09252d, 0xc208e69f,
0xb74e6132, 0xce77e25b, 0x578fdfe3, 0x3ac372e6}};
+
+} // namespace Blowfish
diff --git a/main.cpp b/main.cpp
index 263438d..2a46d8c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -12,7 +12,7 @@ constexpr uint64_t k(const uint8_t key[8]) {
template <int i> struct wrapper {
constexpr void operator()() const {
- constexpr Blowfish b(variable_key[i], 8);
+ constexpr Blowfish::Context<8> b(std::to_array(variable_key[i]));
constexpr Blowfish::Block x(plaintext_l[i], plaintext_r[i]);
constexpr auto y = b.encrypt(x);