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diff --git a/drivers/staging/skein/include/threefishApi.h b/drivers/staging/skein/include/threefishApi.h
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+
+#ifndef THREEFISHAPI_H
+#define THREEFISHAPI_H
+
+/**
+ * @file threefishApi.h
+ * @brief A Threefish cipher API and its functions.
+ * @{
+ *
+ * This API and the functions that implement this API simplify the usage
+ * of the Threefish cipher. The design and the way to use the functions 
+ * follow the openSSL design but at the same time take care of some Threefish
+ * specific behaviour and possibilities.
+ *
+ * These are the low level functions that deal with Threefisch blocks only.
+ * Implementations for cipher modes such as ECB, CFB, or CBC may use these 
+ * functions.
+ * 
+@code
+    // Threefish cipher context data
+    ThreefishKey_t keyCtx;
+
+    // Initialize the context
+    threefishSetKey(&keyCtx, Threefish512, key, tweak);
+
+    // Encrypt
+    threefishEncryptBlockBytes(&keyCtx, input, cipher);
+@endcode
+ */
+
+#include <skein.h>
+#include <stdint.h>
+
+#define KeyScheduleConst 0x1BD11BDAA9FC1A22L
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /**
+     * Which Threefish size to use
+     */
+    typedef enum ThreefishSize {
+        Threefish256 = 256,     /*!< Skein with 256 bit state */
+        Threefish512 = 512,     /*!< Skein with 512 bit state */
+        Threefish1024 = 1024    /*!< Skein with 1024 bit state */
+    } ThreefishSize_t;
+    
+    /**
+     * Context for Threefish key and tweak words.
+     * 
+     * This structure was setup with some know-how of the internal
+     * Skein structures, in particular ordering of header and size dependent
+     * variables. If Skein implementation changes this, the adapt these
+     * structures as well.
+     */
+    typedef struct ThreefishKey {
+        u64b_t stateSize;
+        u64b_t key[SKEIN_MAX_STATE_WORDS+1];   /* max number of key words*/
+        u64b_t tweak[3];
+    } ThreefishKey_t;
+
+    /**
+     * Set Threefish key and tweak data.
+     * 
+     * This function sets the key and tweak data for the Threefish cipher of
+     * the given size. The key data must have the same length (number of bits)
+     * as the state size 
+     *
+     * @param keyCtx
+     *     Pointer to a Threefish key structure.
+     * @param size
+     *     Which Skein size to use.
+     * @param keyData
+     *     Pointer to the key words (word has 64 bits).
+     * @param tweak
+     *     Pointer to the two tweak words (word has 64 bits).
+     */
+    void threefishSetKey(ThreefishKey_t* keyCtx, ThreefishSize_t stateSize, uint64_t* keyData, uint64_t* tweak);
+    
+    /**
+     * Encrypt Threefisch block (bytes).
+     * 
+     * The buffer must have at least the same length (number of bits) aas the 
+     * state size for this key. The function uses the first @c stateSize bits
+     * of the input buffer, encrypts them and stores the result in the output
+     * buffer.
+     * 
+     * @param keyCtx
+     *     Pointer to a Threefish key structure.
+     * @param in
+     *     Poionter to plaintext data buffer.
+     * @param out
+     *     Pointer to cipher buffer.
+     */
+    void threefishEncryptBlockBytes(ThreefishKey_t* keyCtx, uint8_t* in, uint8_t* out);
+    
+    /**
+     * Encrypt Threefisch block (words).
+     * 
+     * The buffer must have at least the same length (number of bits) aas the 
+     * state size for this key. The function uses the first @c stateSize bits
+     * of the input buffer, encrypts them and stores the result in the output
+     * buffer.
+     * 
+     * The wordsize ist set to 64 bits.
+     * 
+     * @param keyCtx
+     *     Pointer to a Threefish key structure.
+     * @param in
+     *     Poionter to plaintext data buffer.
+     * @param out
+     *     Pointer to cipher buffer.
+     */
+    void threefishEncryptBlockWords(ThreefishKey_t* keyCtx, uint64_t* in, uint64_t* out);
+
+    /**
+     * Decrypt Threefisch block (bytes).
+     * 
+     * The buffer must have at least the same length (number of bits) aas the 
+     * state size for this key. The function uses the first @c stateSize bits
+     * of the input buffer, decrypts them and stores the result in the output
+     * buffer
+     * 
+     * @param keyCtx
+     *     Pointer to a Threefish key structure.
+     * @param in
+     *     Poionter to cipher data buffer.
+     * @param out
+     *     Pointer to plaintext buffer.
+     */
+    void threefishDecryptBlockBytes(ThreefishKey_t* keyCtx, uint8_t* in, uint8_t* out);
+
+    /**
+     * Decrypt Threefisch block (words).
+     * 
+     * The buffer must have at least the same length (number of bits) aas the 
+     * state size for this key. The function uses the first @c stateSize bits
+     * of the input buffer, encrypts them and stores the result in the output
+     * buffer.
+     * 
+     * The wordsize ist set to 64 bits.
+     * 
+     * @param keyCtx
+     *     Pointer to a Threefish key structure.
+     * @param in
+     *     Poionter to cipher data buffer.
+     * @param out
+     *     Pointer to plaintext buffer.
+     */
+    void threefishDecryptBlockWords(ThreefishKey_t* keyCtx, uint64_t* in, uint64_t* out);
+
+    void threefishEncrypt256(ThreefishKey_t* keyCtx, uint64_t* input, uint64_t* output);
+    void threefishEncrypt512(ThreefishKey_t* keyCtx, uint64_t* input, uint64_t* output);
+    void threefishEncrypt1024(ThreefishKey_t* keyCtx, uint64_t* input, uint64_t* output);
+    void threefishDecrypt256(ThreefishKey_t* keyCtx, uint64_t* input, uint64_t* output);
+    void threefishDecrypt512(ThreefishKey_t* keyCtx, uint64_t* input, uint64_t* output);
+    void threefishDecrypt1024(ThreefishKey_t* keyCtx, uint64_t* input, uint64_t* output);
+#ifdef __cplusplus
+}
+#endif
+
+/**
+ * @}
+ */
+#endif