Crypto++  8.2
Free C++ class library of cryptographic schemes
hmac.cpp
1 // hmac.cpp - originally written and placed in the public domain by Wei Dai
2 
3 #include "pch.h"
4 
5 #ifndef CRYPTOPP_IMPORTS
6 
7 #include "hmac.h"
8 
9 NAMESPACE_BEGIN(CryptoPP)
10 
11 void HMAC_Base::UncheckedSetKey(const byte *userKey, unsigned int keylength, const NameValuePairs &)
12 {
13  AssertValidKeyLength(keylength);
14 
15  Restart();
16 
17  HashTransformation &hash = AccessHash();
18  unsigned int blockSize = hash.BlockSize();
19 
20  if (!blockSize)
21  throw InvalidArgument("HMAC: can only be used with a block-based hash function");
22 
23  m_buf.resize(2*AccessHash().BlockSize() + AccessHash().DigestSize());
24 
25  if (keylength <= blockSize)
26  {
27  // hmac.cpp:26:9: runtime error: null pointer passed as argument 2
28  if (AccessIpad() && userKey && keylength)
29  memcpy(AccessIpad(), userKey, keylength);
30  }
31  else
32  {
33  AccessHash().CalculateDigest(AccessIpad(), userKey, keylength);
34  keylength = hash.DigestSize();
35  }
36 
37  CRYPTOPP_ASSERT(keylength <= blockSize);
38  memset(AccessIpad()+keylength, 0, blockSize-keylength);
39 
40  for (unsigned int i=0; i<blockSize; i++)
41  {
42  AccessOpad()[i] = AccessIpad()[i] ^ 0x5c;
43  AccessIpad()[i] ^= 0x36;
44  }
45 }
46 
47 void HMAC_Base::KeyInnerHash()
48 {
49  CRYPTOPP_ASSERT(!m_innerHashKeyed);
50  HashTransformation &hash = AccessHash();
51  hash.Update(AccessIpad(), hash.BlockSize());
52  m_innerHashKeyed = true;
53 }
54 
56 {
57  if (m_innerHashKeyed)
58  {
59  AccessHash().Restart();
60  m_innerHashKeyed = false;
61  }
62 }
63 
64 void HMAC_Base::Update(const byte *input, size_t length)
65 {
66  if (!m_innerHashKeyed)
67  KeyInnerHash();
68  AccessHash().Update(input, length);
69 }
70 
71 void HMAC_Base::TruncatedFinal(byte *mac, size_t size)
72 {
73  ThrowIfInvalidTruncatedSize(size);
74 
75  HashTransformation &hash = AccessHash();
76 
77  if (!m_innerHashKeyed)
78  KeyInnerHash();
79  hash.Final(AccessInnerHash());
80 
81  hash.Update(AccessOpad(), hash.BlockSize());
82  hash.Update(AccessInnerHash(), hash.DigestSize());
83  hash.TruncatedFinal(mac, size);
84 
85  m_innerHashKeyed = false;
86 }
87 
88 NAMESPACE_END
89 
90 #endif
virtual unsigned int BlockSize() const
Provides the block size of the compression function.
Definition: cryptlib.h:1165
const char * DigestSize()
int, in bytes
Definition: argnames.h:79
An invalid argument was detected.
Definition: cryptlib.h:202
virtual void TruncatedFinal(byte *digest, size_t digestSize)=0
Computes the hash of the current message.
Classes for HMAC message authentication codes.
HMAC information.
Definition: hmac.h:17
virtual void Restart()
Restart the hash.
Definition: cryptlib.h:1147
Precompiled header file.
void Update(const byte *input, size_t length)
Updates a hash with additional input.
Definition: hmac.cpp:64
void Restart()
Restart the hash.
Definition: hmac.cpp:55
#define CRYPTOPP_ASSERT(exp)
Debugging and diagnostic assertion.
Definition: trap.h:69
void TruncatedFinal(byte *mac, size_t size)
Computes the hash of the current message.
Definition: hmac.cpp:71
const char * BlockSize()
int, in bytes
Definition: argnames.h:27
virtual unsigned int DigestSize() const =0
Provides the digest size of the hash.
Interface for hash functions and data processing part of MACs.
Definition: cryptlib.h:1112
Crypto++ library namespace.
virtual void Final(byte *digest)
Computes the hash of the current message.
Definition: cryptlib.h:1142
virtual void Update(const byte *input, size_t length)=0
Updates a hash with additional input.
Interface for retrieving values given their names.
Definition: cryptlib.h:321