From 7fb5953055d14307a9d4ae95fd6499f3a48f8b95 Mon Sep 17 00:00:00 2001
From: Jeffrey Walton <noloader@gmail.com>
Date: Sat, 19 Aug 2017 15:41:45 -0400
Subject: Add VIA Padlock RNG

---
 padlkrng.h | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 padlkrng.h

(limited to 'padlkrng.h')

diff --git a/padlkrng.h b/padlkrng.h
new file mode 100644
index 00000000..9a70fd87
--- /dev/null
+++ b/padlkrng.h
@@ -0,0 +1,70 @@
+// via-rng.h - written and placed in public domain by Jeffrey Walton
+
+//! \file PadlockRNG.h
+//! \brief Class for VIA Padlock RNG
+//! \since Crypto++ 6.0
+
+#ifndef CRYPTOPP_PADLOCK_RNG_H
+#define CRYPTOPP_PADLOCK_RNG_H
+
+#include "cryptlib.h"
+#include "secblock.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+//! \brief Exception thrown when a PadlockRNG generator encounters
+//!    a generator related error.
+//! \since Crypto++ 6.0
+class PadlockRNG_Err : public Exception
+{
+public:
+    PadlockRNG_Err(const std::string &operation)
+        : Exception(OTHER_ERROR, "PadlockRNG: " + operation + " operation failed") {}
+};
+
+//! \brief Hardware generated random numbers using PadlockRNG instruction
+//! \sa MaurerRandomnessTest() for random bit generators
+//! \since Crypto++ 6.0
+class PadlockRNG : public RandomNumberGenerator
+{
+public:
+    CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() { return "PadlockRNG"; }
+
+    virtual ~PadlockRNG() {}
+
+    //! \brief Construct a PadlockRNG generator
+    //! \details According to DJ of Intel, the Intel PadlockRNG circuit does not underflow.
+    //!   If it did hypothetically underflow, then it would return 0 for the random value.
+    //!   AMD's PadlockRNG implementation appears to provide the same behavior.
+     //! \throws PadlockRNG_Err if the random number generator is not available
+    PadlockRNG();
+
+    //! \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);
+    }
+
+private:
+	FixedSizeAlignedSecBlock<word32, 1, true> m_buffer;
+};
+
+NAMESPACE_END
+
+#endif  // CRYPTOPP_PADLOCK_RNG_H
-- 
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