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+// Purpose: Header file for the C++ ICE encryption class.
+//			Taken from public domain code, as written by Matthew Kwan - July 1996
+//			http://www.darkside.com.au/ice/
+
+#ifndef _IceKey_H
+#define _IceKey_H
+
+/*
+The IceKey class is used for encrypting and decrypting 64-bit blocks of data 
+with the ICE (Information Concealment Engine) encryption algorithm. 
+
+The constructor creates a new IceKey object that can be used to encrypt and decrypt data. 
+The level of encryption determines the size of the key, and hence its speed. 
+Level 0 uses the Thin-ICE variant, which is an 8-round cipher taking an 8-byte key. 
+This is the fastest option, and is generally considered to be at least as secure as DES, 
+although it is not yet certain whether it is as secure as its key size. 
+
+For levels n greater than zero, a 16n-round cipher is used, taking 8n-byte keys. 
+Although not as fast as level 0, these are very very secure. 
+
+Before an IceKey can be used to encrypt data, its key schedule must be set with the set() member function. 
+The length of the key required is determined by the level, as described above. 
+
+The member functions encrypt() and decrypt() encrypt and decrypt respectively data 
+in blocks of eight chracters, using the specified key. 
+
+Two functions keySize() and blockSize() are provided 
+which return the key and block size respectively, measured in bytes. 
+The key size is determined by the level, while the block size is always 8. 
+
+The destructor zeroes out and frees up all memory associated with the key. 
+*/
+
+class IceSubkey;
+
+class IceKey {
+    public:
+	IceKey (int n);
+	~IceKey ();
+
+	void		set (const unsigned char *key);
+
+	void		encrypt (const unsigned char *plaintext,
+					unsigned char *ciphertext) const;
+
+	void		decrypt (const unsigned char *ciphertext,
+					unsigned char *plaintext) const;
+
+	int		keySize () const;
+
+	int		blockSize () const;
+
+    private:
+	void		scheduleBuild (unsigned short *k, int n,
+							const int *keyrot);
+
+	int		_size;
+	int		_rounds;
+	IceSubkey	*_keysched;
+};
+
+#endif