1 files changed, 39 insertions, 0 deletions
diff --git a/gf28.h b/gf28.h
new file mode 100644
index 0000000..194cd57
--- /dev/null
+++ b/gf28.h
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+#pragma once
+
+#include <iostream>
+#include <cstdint>
+
+//The GF(2^8) field used in AES
+
+class GF28{
+	int value;
+
+	static int reduce(int v,int m);
+
+public:
+	static const int modulus=0x11b;
+
+	static uint8_t multiply(uint8_t x,uint8_t y); //for when the class is overkill
+
+	GF28();
+	explicit GF28(int v);
+
+	explicit operator uint8_t() const;
+
+	GF28& operator+=(GF28 o);
+	GF28& operator-=(GF28 o);
+	GF28& operator<<=(int n); //multiplication by x^n
+
+	GF28 operator+(GF28 o) const;
+	GF28 operator-(GF28 o) const;
+	GF28 operator*(GF28 o) const;
+	GF28 operator<<(int n) const; //multiplication by x^n
+
+	bool operator==(GF28 o) const;
+
+	GF28 inverse() const;
+
+	friend std::ostream& operator<<(std::ostream&,GF28);
+};
+
+std::ostream& operator<<(std::ostream &os,GF28 p);