Coverage Report

Created: 2020-02-14 15:38

/src/botan/src/lib/block/cascade/cascade.cpp
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Source (jump to first uncovered line)
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/*
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* Block Cipher Cascade
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* (C) 2010 Jack Lloyd
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*
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* Botan is released under the Simplified BSD License (see license.txt)
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*/
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#include <botan/cascade.h>
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namespace Botan {
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void Cascade_Cipher::encrypt_n(const uint8_t in[], uint8_t out[],
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                               size_t blocks) const
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   {
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   size_t c1_blocks = blocks * (block_size() / m_cipher1->block_size());
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   size_t c2_blocks = blocks * (block_size() / m_cipher2->block_size());
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   m_cipher1->encrypt_n(in, out, c1_blocks);
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   m_cipher2->encrypt_n(out, out, c2_blocks);
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   }
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void Cascade_Cipher::decrypt_n(const uint8_t in[], uint8_t out[],
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                               size_t blocks) const
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   {
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   size_t c1_blocks = blocks * (block_size() / m_cipher1->block_size());
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   size_t c2_blocks = blocks * (block_size() / m_cipher2->block_size());
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   m_cipher2->decrypt_n(in, out, c2_blocks);
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   m_cipher1->decrypt_n(out, out, c1_blocks);
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   }
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void Cascade_Cipher::key_schedule(const uint8_t key[], size_t)
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   {
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   const uint8_t* key2 = key + m_cipher1->maximum_keylength();
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   m_cipher1->set_key(key , m_cipher1->maximum_keylength());
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   m_cipher2->set_key(key2, m_cipher2->maximum_keylength());
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   }
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void Cascade_Cipher::clear()
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   {
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   m_cipher1->clear();
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   m_cipher2->clear();
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   }
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std::string Cascade_Cipher::name() const
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   {
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   return "Cascade(" + m_cipher1->name() + "," + m_cipher2->name() + ")";
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   }
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BlockCipher* Cascade_Cipher::clone() const
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   {
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   return new Cascade_Cipher(m_cipher1->clone(),
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                             m_cipher2->clone());
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   }
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namespace {
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size_t euclids_algorithm(size_t a, size_t b)
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   {
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   while(b != 0)
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      {
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      size_t t = b;
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      b = a % b;
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      a = t;
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      }
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   return a;
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   }
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size_t block_size_for_cascade(size_t bs, size_t bs2)
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   {
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   if(bs == bs2)
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      return bs;
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   const size_t gcd = euclids_algorithm(bs, bs2);
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   return (bs * bs2) / gcd;
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   }
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}
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Cascade_Cipher::Cascade_Cipher(BlockCipher* c1, BlockCipher* c2) :
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   m_cipher1(c1), m_cipher2(c2)
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   {
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   m_block = block_size_for_cascade(c1->block_size(), c2->block_size());
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   BOTAN_ASSERT(m_block % c1->block_size() == 0 &&
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                m_block % c2->block_size() == 0,
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                "Combined block size is a multiple of each ciphers block");
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   }
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}