Remove cryptoppwin submodule (#754)

third_party/cryptoppwin/include/cryptopp/darn.h

@@ -0,0 +1,95 @@
+// darn.h - written and placed in public domain by Jeffrey Walton
+//          DARN requires POWER9/ISA 3.0.
+
+// At the moment only GCC 7.0 (and above) seems to support __builtin_darn()
+// and __builtin_darn_32(). However, GCC generates incorrect code. Clang 7.0
+// does not provide them, but it does support assembly instructions. XLC is
+// unknown, but there are no hits when searching IBM's site. To cover more
+// platforms we provide GCC inline assembly like we do with RDRAND and RDSEED.
+// Platforms that don't support GCC inline assembly or the builtin will fail
+// to compile. Also see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91481 and
+// https://gcc.gnu.org/onlinedocs/gcc/Basic-PowerPC-Built-in-Functions-Available-on-ISA-3_002e0.html
+
+/// \file darn.h
+/// \brief Classes for DARN RNG
+/// \sa <A HREF="https://openpowerfoundation.org/?resource_lib=power-isa-version-3-0">Power
+///   ISA Version 3.0B</A>
+/// \since Crypto++ 8.0
+
+#ifndef CRYPTOPP_DARN_H
+#define CRYPTOPP_DARN_H
+
+#include "cryptlib.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+/// \brief Exception thrown when a DARN generator encounters
+///    a generator related error.
+/// \since Crypto++ 8.0
+class DARN_Err : public Exception
+{
+public:
+    DARN_Err(const std::string &operation)
+        : Exception(OTHER_ERROR, "DARN: " + operation + " operation failed") {}
+};
+
+/// \brief Hardware generated random numbers using DARN instruction
+/// \details DARN() provides access to Power9's random number generator. The
+///   Crypto++ implementation provides conditioned random numbers from the
+///   generator as opposed to raw random numbers. According to Power ISA 3.0B
+///   manual, a conditioned random number has been processed by hardware to
+///   reduce bias. A raw random number is unconditioned noise source output.
+/// \details According to Power ISA 3.0B manual, the random number generator
+///   provided by the <tt>darn</tt> instruction is NIST SP800-90B and SP800-90C
+///   compliant to the extent possible given the completeness of the standards
+///   at the time the hardware is designed. The random number generator provides
+///   a minimum of 0.5 bits of entropy per bit.
+/// \par Wraps
+///   darn instruction
+/// \sa <A HREF="https://openpowerfoundation.org/?resource_lib=power-isa-version-3-0">Power
+///   ISA Version 3.0B</A>, MaurerRandomnessTest() for random bit generators
+/// \since Crypto++ 8.0
+class DARN : public RandomNumberGenerator
+{
+public:
+    CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() { return "DARN"; }
+
+    virtual ~DARN() {}
+
+    /// \brief Construct a DARN generator
+     /// \throw DARN_Err if the random number generator is not available
+    DARN();
+
+    /// \brief Generate random array of bytes
+    /// \param output the byte buffer
+    /// \param size the length of the buffer, in bytes
+    virtual void GenerateBlock(byte *output, size_t size);
+
+    /// \brief Generate and discard n bytes
+    /// \param n the number of bytes to generate and discard
+    /// \details the RDSEED generator discards words, not bytes. If n is
+    ///   not a multiple of a machine word, then it is rounded up to
+    ///   that size.
+    virtual void DiscardBytes(size_t n);
+
+    /// \brief Update RNG state with additional unpredictable values
+    /// \param input unused
+    /// \param length unused
+    /// \details The operation is a nop for this generator.
+    virtual void IncorporateEntropy(const byte *input, size_t length)
+    {
+        // Override to avoid the base class' throw.
+        CRYPTOPP_UNUSED(input); CRYPTOPP_UNUSED(length);
+    }
+
+    std::string AlgorithmProvider() const {
+        return "Power9";
+    }
+
+private:
+    SecBlock<byte, AllocatorWithCleanup<byte, true> > m_temp;
+};
+
+NAMESPACE_END
+
+#endif // CRYPTOPP_DARN_H