1 // shake.cpp - modified by Wei Dai from Ronny Van Keer's public domain
2 // sha3-simple.c. All modifications here are placed in the
3 // public domain by Wei Dai.
4 // Keccack core function moved to keccakc.cpp in AUG 2018
5 // by Jeffrey Walton. Separating the core file allows both
6 // SHA3 and Keccack to share the core implementation.
7
8 /*
9 The SHAKE sponge function, designed by Guido Bertoni, Joan Daemen,
10 Michael Peeters and Gilles Van Assche. For more information, feedback or
11 questions, please refer to our website: http://keccak.noekeon.org/
12
13 Implementation by Ronny Van Keer, hereby denoted as "the implementer".
14
15 To the extent possible under law, the implementer has waived all copyright
16 and related or neighboring rights to the source code in this file.
17 http://creativecommons.org/publicdomain/zero/1.0/
18 */
19
20 #include "pch.h"
21 #include "shake.h"
22
23 NAMESPACE_BEGIN(CryptoPP)
24
25 // The Keccak core function
26 extern void KeccakF1600(word64 *state);
27
Update(const byte * input,size_t length)28 void SHAKE::Update(const byte *input, size_t length)
29 {
30 CRYPTOPP_ASSERT(!(input == NULLPTR && length != 0));
31 if (length == 0) { return; }
32
33 size_t spaceLeft;
34 while (length >= (spaceLeft = r() - m_counter))
35 {
36 if (spaceLeft)
37 xorbuf(m_state.BytePtr() + m_counter, input, spaceLeft);
38 KeccakF1600(m_state);
39 input += spaceLeft;
40 length -= spaceLeft;
41 m_counter = 0;
42 }
43
44 if (length)
45 xorbuf(m_state.BytePtr() + m_counter, input, length);
46 m_counter += (unsigned int)length;
47 }
48
Restart()49 void SHAKE::Restart()
50 {
51 memset(m_state, 0, m_state.SizeInBytes());
52 m_counter = 0;
53 }
54
ThrowIfInvalidTruncatedSize(size_t size) const55 void SHAKE::ThrowIfInvalidTruncatedSize(size_t size) const
56 {
57 if (size > UINT_MAX)
58 throw InvalidArgument(std::string("HashTransformation: can't truncate a ") +
59 IntToString(UINT_MAX) + " byte digest to " + IntToString(size) + " bytes");
60 }
61
TruncatedFinal(byte * hash,size_t size)62 void SHAKE::TruncatedFinal(byte *hash, size_t size)
63 {
64 CRYPTOPP_ASSERT(hash != NULLPTR);
65 ThrowIfInvalidTruncatedSize(size);
66
67 m_state.BytePtr()[m_counter] ^= 0x1F;
68 m_state.BytePtr()[r()-1] ^= 0x80;
69
70 // FIPS 202, Algorithm 8, pp 18-19.
71 while (size > 0)
72 {
73 KeccakF1600(m_state);
74
75 const size_t segmentLen = STDMIN(size, (size_t)BlockSize());
76 std::memcpy(hash, m_state, segmentLen);
77
78 hash += segmentLen;
79 size -= segmentLen;
80 }
81
82 Restart();
83 }
84
85 NAMESPACE_END
86