First Commit

externals/cryptopp/shake.cpp

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+// shake.cpp - modified by Wei Dai from Ronny Van Keer's public domain
+//             sha3-simple.c. All modifications here are placed in the
+//             public domain by Wei Dai.
+//             Keccack core function moved to keccakc.cpp in AUG 2018
+//             by Jeffrey Walton. Separating the core file allows both
+//             SHA3 and Keccack to share the core implementation.
+
+/*
+The SHAKE sponge function, designed by Guido Bertoni, Joan Daemen,
+Michael Peeters and Gilles Van Assche. For more information, feedback or
+questions, please refer to our website: http://keccak.noekeon.org/
+
+Implementation by Ronny Van Keer, hereby denoted as "the implementer".
+
+To the extent possible under law, the implementer has waived all copyright
+and related or neighboring rights to the source code in this file.
+http://creativecommons.org/publicdomain/zero/1.0/
+*/
+
+#include "pch.h"
+#include "shake.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+// The Keccak core function
+extern void KeccakF1600(word64 *state);
+
+void SHAKE::Update(const byte *input, size_t length)
+{
+    CRYPTOPP_ASSERT(!(input == NULLPTR && length != 0));
+    if (length == 0) { return; }
+
+    size_t spaceLeft;
+    while (length >= (spaceLeft = r() - m_counter))
+    {
+        if (spaceLeft)
+            xorbuf(m_state.BytePtr() + m_counter, input, spaceLeft);
+        KeccakF1600(m_state);
+        input += spaceLeft;
+        length -= spaceLeft;
+        m_counter = 0;
+    }
+
+    if (length)
+        xorbuf(m_state.BytePtr() + m_counter, input, length);
+    m_counter += (unsigned int)length;
+}
+
+void SHAKE::Restart()
+{
+    std::memset(m_state, 0, m_state.SizeInBytes());
+    m_counter = 0;
+}
+
+void SHAKE::ThrowIfInvalidTruncatedSize(size_t size) const
+{
+	if (size > UINT_MAX)
+		throw InvalidArgument(std::string("HashTransformation: can't truncate a ") +
+		    IntToString(UINT_MAX) + " byte digest to " + IntToString(size) + " bytes");
+}
+
+void SHAKE::TruncatedFinal(byte *hash, size_t size)
+{
+    CRYPTOPP_ASSERT(hash != NULLPTR);
+    ThrowIfInvalidTruncatedSize(size);
+
+    m_state.BytePtr()[m_counter] ^= 0x1F;
+    m_state.BytePtr()[r()-1] ^= 0x80;
+
+    // FIPS 202, Algorithm 8, pp 18-19.
+    while (size > 0)
+    {
+        KeccakF1600(m_state);
+
+        const size_t segmentLen = STDMIN(size, (size_t)BlockSize());
+        std::memcpy(hash, m_state, segmentLen);
+
+        hash += segmentLen;
+        size -= segmentLen;
+    }
+
+    Restart();
+}
+
+NAMESPACE_END