Arduino Cryptography Library
CBC.cpp
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22 
23 #include "CBC.h"
24 #include "Crypto.h"
25 #include <string.h>
26 
43  : blockCipher(0)
44  , posn(16)
45 {
46 }
47 
52 {
53  clean(iv);
54  clean(temp);
55 }
56 
57 size_t CBCCommon::keySize() const
58 {
59  return blockCipher->keySize();
60 }
61 
62 size_t CBCCommon::ivSize() const
63 {
64  return 16;
65 }
66 
67 bool CBCCommon::setKey(const uint8_t *key, size_t len)
68 {
69  // Verify the cipher's block size, just in case.
70  if (blockCipher->blockSize() != 16)
71  return false;
72 
73  // Set the key on the underlying block cipher.
74  return blockCipher->setKey(key, len);
75 }
76 
77 bool CBCCommon::setIV(const uint8_t *iv, size_t len)
78 {
79  if (len != 16)
80  return false;
81  memcpy(this->iv, iv, 16);
82  posn = 16;
83  return true;
84 }
85 
86 void CBCCommon::encrypt(uint8_t *output, const uint8_t *input, size_t len)
87 {
88  uint8_t posn;
89  while (len >= 16) {
90  for (posn = 0; posn < 16; ++posn)
91  iv[posn] ^= *input++;
92  blockCipher->encryptBlock(iv, iv);
93  for (posn = 0; posn < 16; ++posn)
94  *output++ = iv[posn];
95  len -= 16;
96  }
97 }
98 
99 void CBCCommon::decrypt(uint8_t *output, const uint8_t *input, size_t len)
100 {
101  uint8_t posn;
102  while (len >= 16) {
103  blockCipher->decryptBlock(temp, input);
104  for (posn = 0; posn < 16; ++posn) {
105  uint8_t in = *input++;
106  *output++ = temp[posn] ^ iv[posn];
107  iv[posn] = in;
108  }
109  len -= 16;
110  }
111 }
112 
114 {
115  blockCipher->clear();
116  clean(iv);
117  clean(temp);
118  posn = 16;
119 }
120 
virtual void clear()=0
Clears all security-sensitive state from this block cipher.
virtual size_t blockSize() const =0
Size of a single block processed by this cipher, in bytes.
virtual bool setKey(const uint8_t *key, size_t len)=0
Sets the key to use for future encryption and decryption operations.
virtual void decryptBlock(uint8_t *output, const uint8_t *input)=0
Decrypts a single block using this cipher.
virtual void encryptBlock(uint8_t *output, const uint8_t *input)=0
Encrypts a single block using this cipher.
virtual size_t keySize() const =0
Default size of the key for this block cipher, in bytes.
size_t ivSize() const
Size of the initialization vector for this cipher, in bytes.
Definition: CBC.cpp:62
void encrypt(uint8_t *output, const uint8_t *input, size_t len)
Encrypts an input buffer and writes the ciphertext to an output buffer.
Definition: CBC.cpp:86
virtual ~CBCCommon()
Destroys this cipher object after clearing sensitive information.
Definition: CBC.cpp:51
CBCCommon()
Constructs a new cipher in CBC mode.
Definition: CBC.cpp:42
void clear()
Clears all security-sensitive state from this cipher.
Definition: CBC.cpp:113
void decrypt(uint8_t *output, const uint8_t *input, size_t len)
Decrypts an input buffer and writes the plaintext to an output buffer.
Definition: CBC.cpp:99
bool setIV(const uint8_t *iv, size_t len)
Sets the initialization vector to use for future encryption and decryption operations.
Definition: CBC.cpp:77
bool setKey(const uint8_t *key, size_t len)
Sets the key to use for future encryption and decryption operations.
Definition: CBC.cpp:67
size_t keySize() const
Default size of the key for this cipher, in bytes.
Definition: CBC.cpp:57