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-rw-r--r--src/aead/ocb/ocb.cpp444
1 files changed, 0 insertions, 444 deletions
diff --git a/src/aead/ocb/ocb.cpp b/src/aead/ocb/ocb.cpp
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index 4cbd8bde8..000000000
--- a/src/aead/ocb/ocb.cpp
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@@ -1,444 +0,0 @@
-/*
-* OCB Mode
-* (C) 2013 Jack Lloyd
-*
-* Distributed under the terms of the Botan license
-*/
-
-#include <botan/ocb.h>
-#include <botan/cmac.h>
-#include <botan/internal/xor_buf.h>
-#include <botan/internal/bit_ops.h>
-#include <algorithm>
-
-namespace Botan {
-
-// Has to be in Botan namespace so unique_ptr can reference it
-class L_computer
- {
- public:
- L_computer(const BlockCipher& cipher)
- {
- m_L_star.resize(cipher.block_size());
- cipher.encrypt(m_L_star);
- m_L_dollar = poly_double(star());
- m_L.push_back(poly_double(dollar()));
- }
-
- const secure_vector<byte>& star() const { return m_L_star; }
-
- const secure_vector<byte>& dollar() const { return m_L_dollar; }
-
- const secure_vector<byte>& operator()(size_t i) const { return get(i); }
-
- const secure_vector<byte>& get(size_t i) const
- {
- while(m_L.size() <= i)
- m_L.push_back(poly_double(m_L.back()));
-
- return m_L.at(i);
- }
-
- private:
- secure_vector<byte> poly_double(const secure_vector<byte>& in) const
- {
- return CMAC::poly_double(in, 0x87);
- }
-
- secure_vector<byte> m_L_dollar, m_L_star;
- mutable std::vector<secure_vector<byte>> m_L;
- };
-
-class Nonce_State
- {
- public:
- Nonce_State(const BlockCipher& cipher) : m_cipher(cipher) {}
-
- secure_vector<byte> update_nonce(const byte nonce[],
- size_t nonce_len);
- private:
- const BlockCipher& m_cipher;
- secure_vector<byte> m_last_nonce;
- secure_vector<byte> m_stretch;
- };
-
-secure_vector<byte>
-Nonce_State::update_nonce(const byte nonce[], size_t nonce_len)
- {
- const size_t BS = 16;
-
- BOTAN_ASSERT(nonce_len < BS, "Nonce is less than 128 bits");
-
- secure_vector<byte> nonce_buf(BS);
-
- copy_mem(&nonce_buf[BS - nonce_len], nonce, nonce_len);
- nonce_buf[BS - nonce_len - 1] = 1;
-
- const byte bottom = nonce_buf[15] & 0x3F;
- nonce_buf[15] &= 0xC0;
-
- const bool need_new_stretch = (m_last_nonce != nonce_buf);
-
- if(need_new_stretch)
- {
- m_last_nonce = nonce_buf;
-
- m_cipher.encrypt(nonce_buf);
-
- for(size_t i = 0; i != 8; ++i)
- nonce_buf.push_back(nonce_buf[i] ^ nonce_buf[i+1]);
-
- m_stretch = nonce_buf;
- }
-
- // now set the offset from stretch and bottom
-
- const size_t shift_bytes = bottom / 8;
- const size_t shift_bits = bottom % 8;
-
- secure_vector<byte> offset(BS);
- for(size_t i = 0; i != BS; ++i)
- {
- offset[i] = (m_stretch[i+shift_bytes] << shift_bits);
- offset[i] |= (m_stretch[i+shift_bytes+1] >> (8-shift_bits));
- }
-
- return offset;
- }
-
-namespace {
-
-/*
-* OCB's HASH
-*/
-secure_vector<byte> ocb_hash(const L_computer& L,
- const BlockCipher& cipher,
- const byte ad[], size_t ad_len)
- {
- const size_t BS = cipher.block_size();
-
- secure_vector<byte> sum(BS);
- secure_vector<byte> offset(BS);
-
- secure_vector<byte> buf(BS);
-
- const size_t ad_blocks = (ad_len / BS);
- const size_t ad_remainder = (ad_len % BS);
-
- for(size_t i = 0; i != ad_blocks; ++i)
- {
- // this loop could run in parallel
- offset ^= L(ctz(i+1));
-
- buf = offset;
- xor_buf(&buf[0], &ad[BS*i], BS);
-
- cipher.encrypt(buf);
-
- sum ^= buf;
- }
-
- if(ad_remainder)
- {
- offset ^= L.star();
-
- buf = offset;
- xor_buf(&buf[0], &ad[BS*ad_blocks], ad_remainder);
- buf[ad_len % BS] ^= 0x80;
-
- cipher.encrypt(buf);
-
- sum ^= buf;
- }
-
- return sum;
- }
-
-}
-
-OCB_Mode::OCB_Mode(BlockCipher* cipher, size_t tag_size) :
- m_cipher(cipher),
- m_tag_size(tag_size),
- m_ad_hash(BS), m_offset(BS), m_checksum(BS)
- {
- if(m_cipher->block_size() != BS)
- throw std::invalid_argument("OCB requires a 128 bit cipher so cannot be used with " +
- m_cipher->name());
-
- if(m_tag_size != 16) // fixme: 64, 96 bits also supported
- throw std::invalid_argument("OCB cannot produce a " + std::to_string(m_tag_size) +
- " byte tag");
-
- }
-
-OCB_Mode::~OCB_Mode() { /* for unique_ptr destructor */ }
-
-void OCB_Mode::clear()
- {
- m_cipher.reset();
- m_L.reset();
- zeroise(m_ad_hash);
- zeroise(m_offset);
- zeroise(m_checksum);
- }
-
-bool OCB_Mode::valid_nonce_length(size_t length) const
- {
- return (length > 0 && length < 16);
- }
-
-std::string OCB_Mode::name() const
- {
- return m_cipher->name() + "/OCB"; // include tag size
- }
-
-size_t OCB_Mode::update_granularity() const
- {
- return 8 * m_cipher->parallel_bytes();
- }
-
-Key_Length_Specification OCB_Mode::key_spec() const
- {
- return m_cipher->key_spec();
- }
-
-void OCB_Mode::key_schedule(const byte key[], size_t length)
- {
- m_cipher->set_key(key, length);
- m_L.reset(new L_computer(*m_cipher));
- m_nonce_state.reset(new Nonce_State(*m_cipher));
- }
-
-void OCB_Mode::set_associated_data(const byte ad[], size_t ad_len)
- {
- BOTAN_ASSERT(m_L, "A key was set");
- m_ad_hash = ocb_hash(*m_L, *m_cipher, &ad[0], ad_len);
- }
-
-secure_vector<byte> OCB_Mode::start(const byte nonce[], size_t nonce_len)
- {
- if(!valid_nonce_length(nonce_len))
- throw Invalid_IV_Length(name(), nonce_len);
-
- BOTAN_ASSERT(m_nonce_state, "A key was set");
-
- m_offset = m_nonce_state->update_nonce(nonce, nonce_len);
- zeroise(m_checksum);
- m_block_index = 0;
-
- return secure_vector<byte>();
- }
-
-void OCB_Encryption::encrypt(byte buffer[], size_t blocks)
- {
- const L_computer& L = *m_L; // convenient name
-
- const size_t par_bytes = m_cipher->parallel_bytes();
-
- BOTAN_ASSERT(par_bytes % BS == 0, "Cipher is parallel in full blocks");
-
- const size_t par_blocks = par_bytes / BS;
-
- secure_vector<byte> csum_accum(par_bytes);
- secure_vector<byte> offsets(par_bytes);
-
- size_t blocks_left = blocks;
-
- while(blocks_left)
- {
- const size_t proc_blocks = std::min(blocks_left, par_blocks);
- const size_t proc_bytes = proc_blocks * BS;
-
- for(size_t i = 0; i != proc_blocks; ++i)
- { // could be done in parallel
- m_offset ^= L(ctz(++m_block_index));
- copy_mem(&offsets[BS*i], &m_offset[0], BS);
- }
-
- xor_buf(&csum_accum[0], &buffer[0], proc_bytes);
-
- xor_buf(&buffer[0], &offsets[0], proc_bytes);
-
- m_cipher->encrypt_n(&buffer[0], &buffer[0], proc_blocks);
-
- xor_buf(&buffer[0], &offsets[0], proc_bytes);
-
- buffer += proc_bytes;
- blocks_left -= proc_blocks;
- }
-
- // fold into checksum
- for(size_t i = 0; i != csum_accum.size(); ++i)
- m_checksum[i % BS] ^= csum_accum[i];
- }
-
-void OCB_Encryption::update(secure_vector<byte>& buffer, size_t offset)
- {
- BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
- const size_t sz = buffer.size() - offset;
- byte* buf = &buffer[offset];
-
- BOTAN_ASSERT(sz % BS == 0, "Input length is an even number of blocks");
-
- encrypt(buf, sz / BS);
- }
-
-void OCB_Encryption::finish(secure_vector<byte>& buffer, size_t offset)
- {
- BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
- const size_t sz = buffer.size() - offset;
- byte* buf = &buffer[offset];
-
- if(sz)
- {
- const size_t final_full_blocks = sz / BS;
- const size_t remainder_bytes = sz - (final_full_blocks * BS);
-
- encrypt(buf, final_full_blocks);
-
- if(remainder_bytes)
- {
- BOTAN_ASSERT(remainder_bytes < BS, "Only a partial block left");
- byte* remainder = &buf[sz - remainder_bytes];
-
- xor_buf(&m_checksum[0], &remainder[0], remainder_bytes);
- m_checksum[remainder_bytes] ^= 0x80;
-
- m_offset ^= m_L->star(); // Offset_*
-
- secure_vector<byte> buf(BS);
- m_cipher->encrypt(m_offset, buf);
- xor_buf(&remainder[0], &buf[0], remainder_bytes);
- }
- }
-
- // now compute the tag
- secure_vector<byte> mac = m_offset;
- mac ^= m_checksum;
- mac ^= m_L->dollar();
-
- m_cipher->encrypt(mac);
-
- mac ^= m_ad_hash;
-
- buffer += std::make_pair(&mac[0], tag_size());
-
- zeroise(m_checksum);
- zeroise(m_offset);
- m_block_index = 0;
- }
-
-void OCB_Decryption::decrypt(byte buffer[], size_t blocks)
- {
- const L_computer& L = *m_L; // convenient name
-
- const size_t par_bytes = m_cipher->parallel_bytes();
-
- BOTAN_ASSERT(par_bytes % BS == 0, "Cipher is parallel in full blocks");
-
- const size_t par_blocks = par_bytes / BS;
-
- secure_vector<byte> csum_accum(par_bytes);
- secure_vector<byte> offsets(par_bytes);
-
- size_t blocks_left = blocks;
-
- while(blocks_left)
- {
- const size_t proc_blocks = std::min(blocks_left, par_blocks);
- const size_t proc_bytes = proc_blocks * BS;
-
- for(size_t i = 0; i != proc_blocks; ++i)
- { // could be done in parallel
- m_offset ^= L(ctz(++m_block_index));
- copy_mem(&offsets[BS*i], &m_offset[0], BS);
- }
-
- xor_buf(&buffer[0], &offsets[0], proc_bytes);
-
- m_cipher->decrypt_n(&buffer[0], &buffer[0], proc_blocks);
-
- xor_buf(&buffer[0], &offsets[0], proc_bytes);
-
- xor_buf(&csum_accum[0], &buffer[0], proc_bytes);
-
- buffer += proc_bytes;
- blocks_left -= proc_blocks;
- }
-
- // fold into checksum
- for(size_t i = 0; i != csum_accum.size(); ++i)
- m_checksum[i % BS] ^= csum_accum[i];
- }
-
-void OCB_Decryption::update(secure_vector<byte>& buffer, size_t offset)
- {
- BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
- const size_t sz = buffer.size() - offset;
- byte* buf = &buffer[offset];
-
- BOTAN_ASSERT(sz % BS == 0, "Input length is an even number of blocks");
-
- decrypt(buf, sz / BS);
- }
-
-void OCB_Decryption::finish(secure_vector<byte>& buffer, size_t offset)
- {
- BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
- const size_t sz = buffer.size() - offset;
- byte* buf = &buffer[offset];
-
- BOTAN_ASSERT(sz >= tag_size(), "We have the tag");
-
- const size_t remaining = sz - tag_size();
-
- if(remaining)
- {
- const size_t final_full_blocks = remaining / BS;
- const size_t final_bytes = remaining - (final_full_blocks * BS);
-
- decrypt(&buf[0], final_full_blocks);
-
- if(final_bytes)
- {
- BOTAN_ASSERT(final_bytes < BS, "Only a partial block left");
-
- byte* remainder = &buf[remaining - final_bytes];
-
- m_offset ^= m_L->star(); // Offset_*
-
- secure_vector<byte> pad(BS);
- m_cipher->encrypt(m_offset, pad); // P_*
-
- xor_buf(&remainder[0], &pad[0], final_bytes);
-
- xor_buf(&m_checksum[0], &remainder[0], final_bytes);
- m_checksum[final_bytes] ^= 0x80;
- }
- }
-
- // compute the mac
- secure_vector<byte> mac = m_offset;
- mac ^= m_checksum;
- mac ^= m_L->dollar();
-
- m_cipher->encrypt(mac);
-
- mac ^= m_ad_hash;
-
- // reset state
- zeroise(m_checksum);
- zeroise(m_offset);
- m_block_index = 0;
-
- // compare mac
- const byte* included_tag = &buf[remaining];
-
- if(!same_mem(&mac[0], included_tag, tag_size()))
- throw Integrity_Failure("OCB tag check failed");
-
- // remove tag from end of message
- buffer.resize(remaining + offset);
- }
-
-}
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