Here it is the example code:
/*
* Copyright (C) 2015 Southern Storm Software, Pty Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/*
This example runs tests on the CFB implementation to verify correct behaviour.
*/
#include <Crypto.h>
#include <CryptoLegacy.h>
#include <AES.h>
#include <CFB.h>
#include <string.h>
#define MAX_PLAINTEXT_SIZE 64
#define MAX_CIPHERTEXT_SIZE 64
struct TestVector
{
const char *name;
byte key[16];
byte plaintext[MAX_PLAINTEXT_SIZE];
byte ciphertext[MAX_CIPHERTEXT_SIZE];
byte iv[16];
size_t size;
};
// Test vectors for AES in CFB mode from section F.3 of:
// http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf
static TestVector const testVectorAES128CFB1 = {
.name = "AES-128-CFB #1",
.key = {0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c},
.plaintext = {0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10},
.ciphertext = {0x3b, 0x3f, 0xd9, 0x2e, 0xb7, 0x2d, 0xad, 0x20,
0x33, 0x34, 0x49, 0xf8, 0xe8, 0x3c, 0xfb, 0x4a,
0xc8, 0xa6, 0x45, 0x37, 0xa0, 0xb3, 0xa9, 0x3f,
0xcd, 0xe3, 0xcd, 0xad, 0x9f, 0x1c, 0xe5, 0x8b,
0x26, 0x75, 0x1f, 0x67, 0xa3, 0xcb, 0xb1, 0x40,
0xb1, 0x80, 0x8c, 0xf1, 0x87, 0xa4, 0xf4, 0xdf,
0xc0, 0x4b, 0x05, 0x35, 0x7c, 0x5d, 0x1c, 0x0e,
0xea, 0xc4, 0xc6, 0x6f, 0x9f, 0xf7, 0xf2, 0xe6},
.iv = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
.size = 64
};
static TestVector const testVectorAES128CFB2 = {
// Same as above, but with a short last block to check that
// CFB mode works correctly on non block-aligned plaintext.
.name = "AES-128-CFB #2",
.key = {0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c},
.plaintext = {0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
0xad, 0x2b, 0x41, 0x7b, 0xe6},
.ciphertext = {0x3b, 0x3f, 0xd9, 0x2e, 0xb7, 0x2d, 0xad, 0x20,
0x33, 0x34, 0x49, 0xf8, 0xe8, 0x3c, 0xfb, 0x4a,
0xc8, 0xa6, 0x45, 0x37, 0xa0, 0xb3, 0xa9, 0x3f,
0xcd, 0xe3, 0xcd, 0xad, 0x9f, 0x1c, 0xe5, 0x8b,
0x26, 0x75, 0x1f, 0x67, 0xa3, 0xcb, 0xb1, 0x40,
0xb1, 0x80, 0x8c, 0xf1, 0x87, 0xa4, 0xf4, 0xdf,
0xc0, 0x4b, 0x05, 0x35, 0x7c, 0x5d, 0x1c, 0x0e,
0xea, 0xc4, 0xc6, 0x6f, 0x9f},
.iv = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
.size = 61
};
CFB<AES128> cfbaes128;
byte buffer[128];
bool testCipher_N(Cipher *cipher, const struct TestVector *test, size_t inc)
{
byte output[MAX_CIPHERTEXT_SIZE];
size_t posn, len;
cipher->clear();
if (!cipher->setKey(test->key, cipher->keySize())) {
Serial.print("setKey ");
return false;
}
if (!cipher->setIV(test->iv, cipher->ivSize())) {
Serial.print("setIV ");
return false;
}
memset(output, 0xBA, sizeof(output));
for (posn = 0; posn < test->size; posn += inc) {
len = test->size - posn;
if (len > inc)
len = inc;
cipher->encrypt(output + posn, test->plaintext + posn, len);
}
if (memcmp(output, test->ciphertext, test->size) != 0) {
Serial.print(output[0], HEX);
Serial.print("->");
Serial.print(test->ciphertext[0], HEX);
return false;
}
cipher->setKey(test->key, cipher->keySize());
cipher->setIV(test->iv, cipher->ivSize());
for (posn = 0; posn < test->size; posn += inc) {
len = test->size - posn;
if (len > inc)
len = inc;
cipher->decrypt(output + posn, test->ciphertext + posn, len);
}
if (memcmp(output, test->plaintext, test->size) != 0)
return false;
return true;
}
void testCipher(Cipher *cipher, const struct TestVector *test)
{
bool ok;
Serial.print(test->name);
Serial.print(" ... ");
ok = testCipher_N(cipher, test, test->size);
ok &= testCipher_N(cipher, test, 1);
ok &= testCipher_N(cipher, test, 2);
ok &= testCipher_N(cipher, test, 5);
ok &= testCipher_N(cipher, test, 8);
ok &= testCipher_N(cipher, test, 13);
ok &= testCipher_N(cipher, test, 16);
if (ok)
Serial.println("Passed");
else
Serial.println("Failed");
}
void perfCipherEncrypt(const char *name, Cipher *cipher, const struct TestVector *test)
{
unsigned long start;
unsigned long elapsed;
int count;
Serial.print(name);
Serial.print(" ... ");
cipher->setKey(test->key, cipher->keySize());
cipher->setIV(test->iv, cipher->ivSize());
start = micros();
for (count = 0; count < 500; ++count) {
cipher->encrypt(buffer, buffer, sizeof(buffer));
}
elapsed = micros() - start;
Serial.print(elapsed / (sizeof(buffer) * 500.0));
Serial.print("us per byte, ");
Serial.print((sizeof(buffer) * 500.0 * 1000000.0) / elapsed);
Serial.println(" bytes per second");
}
void perfCipherDecrypt(const char *name, Cipher *cipher, const struct TestVector *test)
{
unsigned long start;
unsigned long elapsed;
int count;
Serial.print(name);
Serial.print(" ... ");
cipher->setKey(test->key, cipher->keySize());
cipher->setIV(test->iv, cipher->ivSize());
start = micros();
for (count = 0; count < 500; ++count) {
cipher->decrypt(buffer, buffer, sizeof(buffer));
}
elapsed = micros() - start;
Serial.print(elapsed / (sizeof(buffer) * 500.0));
Serial.print("us per byte, ");
Serial.print((sizeof(buffer) * 500.0 * 1000000.0) / elapsed);
Serial.println(" bytes per second");
}
void setup()
{
Serial.begin(9600);
Serial.println();
Serial.println("Test Vectors:");
testCipher(&cfbaes128, &testVectorAES128CFB1);
testCipher(&cfbaes128, &testVectorAES128CFB2);
Serial.println();
Serial.println("Performance Tests:");
perfCipherEncrypt("AES-128-CFB Encrypt", &cfbaes128, &testVectorAES128CFB1);
perfCipherDecrypt("AES-128-CFB Decrypt", &cfbaes128, &testVectorAES128CFB1);
}
void loop()
{
}
And as well the reference about CFB using this library (Arduino Cryptography Library: CFBCommon Class Reference), (Arduino Cryptography Library: CFB< T > Class Template Reference)