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-rw-r--r--src/lib/modes/aead/ocb/ocb.cpp92
-rw-r--r--src/lib/modes/aead/ocb/ocb.h8
2 files changed, 52 insertions, 48 deletions
diff --git a/src/lib/modes/aead/ocb/ocb.cpp b/src/lib/modes/aead/ocb/ocb.cpp
index 9a7448161..3e134a642 100644
--- a/src/lib/modes/aead/ocb/ocb.cpp
+++ b/src/lib/modes/aead/ocb/ocb.cpp
@@ -23,13 +23,22 @@ class L_computer final
cipher.encrypt(m_L_star);
m_L_dollar = poly_double(star());
m_L.push_back(poly_double(dollar()));
+
+ while(m_L.size() < 8)
+ m_L.push_back(poly_double(m_L.back()));
}
const secure_vector<uint8_t>& star() const { return m_L_star; }
const secure_vector<uint8_t>& dollar() const { return m_L_dollar; }
- const secure_vector<uint8_t>& operator()(size_t i) const { return get(i); }
+ const secure_vector<uint8_t>& get(size_t i) const
+ {
+ while(m_L.size() <= i)
+ m_L.push_back(poly_double(m_L.back()));
+
+ return m_L[i];
+ }
const secure_vector<uint8_t>&
compute_offsets(secure_vector<uint8_t>& offset,
@@ -37,11 +46,12 @@ class L_computer final
size_t blocks,
size_t BS) const
{
- m_offset_buf.resize(blocks * BS);
+ if(m_offset_buf.size() < blocks * BS)
+ m_offset_buf.resize(blocks * BS);
for(size_t i = 0; i != blocks; ++i)
{ // could be done in parallel
- offset ^= get(ctz(block_index + 1 + i));
+ offset ^= get(ctz<uint32_t>(block_index + 1 + i));
copy_mem(&m_offset_buf[BS*i], offset.data(), BS);
}
@@ -49,14 +59,6 @@ class L_computer final
}
private:
- const secure_vector<uint8_t>& get(size_t i) const
- {
- while(m_L.size() <= i)
- m_L.push_back(poly_double(m_L.back()));
-
- return m_L.at(i);
- }
-
secure_vector<uint8_t> poly_double(const secure_vector<uint8_t>& in) const
{
secure_vector<uint8_t> out(in.size());
@@ -90,7 +92,7 @@ secure_vector<uint8_t> ocb_hash(const L_computer& L,
for(size_t i = 0; i != ad_blocks; ++i)
{
// this loop could run in parallel
- offset ^= L(ctz(i+1));
+ offset ^= L.get(ctz(i+1));
buf = offset;
xor_buf(buf.data(), &ad[BS*i], BS);
@@ -106,7 +108,7 @@ secure_vector<uint8_t> ocb_hash(const L_computer& L,
buf = offset;
xor_buf(buf.data(), &ad[BS*ad_blocks], ad_remainder);
- buf[ad_len % BS] ^= 0x80;
+ buf[ad_remainder] ^= 0x80;
cipher.encrypt(buf);
@@ -123,9 +125,11 @@ OCB_Mode::OCB_Mode(BlockCipher* cipher, size_t tag_size) :
m_checksum(m_cipher->parallel_bytes()),
m_offset(m_cipher->block_size()),
m_ad_hash(m_cipher->block_size()),
- m_tag_size(tag_size)
+ m_tag_size(tag_size),
+ m_block_size(m_cipher->block_size()),
+ m_par_blocks(m_cipher->parallel_bytes() / m_block_size)
{
- const size_t BS = m_cipher->block_size();
+ const size_t BS = block_size();
/*
* draft-krovetz-ocb-wide-d1 specifies OCB for several other block
@@ -162,10 +166,10 @@ bool OCB_Mode::valid_nonce_length(size_t length) const
{
if(length == 0)
return false;
- if(m_cipher->block_size() == 16)
+ if(block_size() == 16)
return length < 16;
else
- return length < (m_cipher->block_size() - 1);
+ return length < (block_size() - 1);
}
std::string OCB_Mode::name() const
@@ -198,7 +202,7 @@ void OCB_Mode::set_associated_data(const uint8_t ad[], size_t ad_len)
secure_vector<uint8_t>
OCB_Mode::update_nonce(const uint8_t nonce[], size_t nonce_len)
{
- const size_t BS = m_cipher->block_size();
+ const size_t BS = block_size();
BOTAN_ASSERT(BS == 16 || BS == 24 || BS == 32 || BS == 64,
"OCB block size is supported");
@@ -300,23 +304,20 @@ void OCB_Mode::start_msg(const uint8_t nonce[], size_t nonce_len)
void OCB_Encryption::encrypt(uint8_t buffer[], size_t blocks)
{
- const size_t BS = m_cipher->block_size();
- const size_t par_blocks = m_checksum.size() / BS;
+ const size_t BS = block_size();
+
+ BOTAN_ASSERT(m_L, "A key was set");
while(blocks)
{
- const size_t proc_blocks = std::min(blocks, par_blocks);
+ const size_t proc_blocks = std::min(blocks, par_blocks());
const size_t proc_bytes = proc_blocks * BS;
- BOTAN_ASSERT(m_L, "A key was set");
-
const auto& offsets = m_L->compute_offsets(m_offset, m_block_index, proc_blocks, BS);
xor_buf(m_checksum.data(), buffer, proc_bytes);
- xor_buf(buffer, offsets.data(), proc_bytes);
- m_cipher->encrypt_n(buffer, buffer, proc_blocks);
- xor_buf(buffer, offsets.data(), proc_bytes);
+ m_cipher->encrypt_n_xex(buffer, offsets.data(), proc_blocks);
buffer += proc_bytes;
blocks -= proc_blocks;
@@ -326,7 +327,7 @@ void OCB_Encryption::encrypt(uint8_t buffer[], size_t blocks)
size_t OCB_Encryption::process(uint8_t buf[], size_t sz)
{
- const size_t BS = m_cipher->block_size();
+ const size_t BS = block_size();
BOTAN_ASSERT(sz % BS == 0, "Invalid OCB input size");
encrypt(buf, sz / BS);
return sz;
@@ -334,7 +335,7 @@ size_t OCB_Encryption::process(uint8_t buf[], size_t sz)
void OCB_Encryption::finish(secure_vector<uint8_t>& buffer, size_t offset)
{
- const size_t BS = m_cipher->block_size();
+ const size_t BS = block_size();
BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
const size_t sz = buffer.size() - offset;
@@ -357,17 +358,19 @@ void OCB_Encryption::finish(secure_vector<uint8_t>& buffer, size_t offset)
m_offset ^= m_L->star(); // Offset_*
- secure_vector<uint8_t> zeros(BS);
- m_cipher->encrypt(m_offset, zeros);
- xor_buf(remainder, zeros.data(), remainder_bytes);
+ secure_vector<uint8_t> pad(BS);
+ m_cipher->encrypt(m_offset, pad);
+ xor_buf(remainder, pad.data(), remainder_bytes);
}
}
secure_vector<uint8_t> checksum(BS);
// fold checksum
- for(size_t i = 0; i != m_checksum.size(); ++i)
- checksum[i % checksum.size()] ^= m_checksum[i];
+ for(size_t i = 0; i != m_checksum.size(); i += BS)
+ {
+ xor_buf(checksum.data(), m_checksum.data() + i, BS);
+ }
// now compute the tag
secure_vector<uint8_t> mac = m_offset;
@@ -385,23 +388,16 @@ void OCB_Encryption::finish(secure_vector<uint8_t>& buffer, size_t offset)
void OCB_Decryption::decrypt(uint8_t buffer[], size_t blocks)
{
- const size_t BS = m_cipher->block_size();
- 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;
+ const size_t BS = block_size();
while(blocks)
{
- const size_t proc_blocks = std::min(blocks, par_blocks);
+ const size_t proc_blocks = std::min(blocks, par_blocks());
const size_t proc_bytes = proc_blocks * BS;
const auto& offsets = m_L->compute_offsets(m_offset, m_block_index, proc_blocks, BS);
- xor_buf(buffer, offsets.data(), proc_bytes);
- m_cipher->decrypt_n(buffer, buffer, proc_blocks);
- xor_buf(buffer, offsets.data(), proc_bytes);
+ m_cipher->decrypt_n_xex(buffer, offsets.data(), proc_blocks);
xor_buf(m_checksum.data(), buffer, proc_bytes);
@@ -413,7 +409,7 @@ void OCB_Decryption::decrypt(uint8_t buffer[], size_t blocks)
size_t OCB_Decryption::process(uint8_t buf[], size_t sz)
{
- const size_t BS = m_cipher->block_size();
+ const size_t BS = block_size();
BOTAN_ASSERT(sz % BS == 0, "Invalid OCB input size");
decrypt(buf, sz / BS);
return sz;
@@ -421,7 +417,7 @@ size_t OCB_Decryption::process(uint8_t buf[], size_t sz)
void OCB_Decryption::finish(secure_vector<uint8_t>& buffer, size_t offset)
{
- const size_t BS = m_cipher->block_size();
+ const size_t BS = block_size();
BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
const size_t sz = buffer.size() - offset;
@@ -459,8 +455,10 @@ void OCB_Decryption::finish(secure_vector<uint8_t>& buffer, size_t offset)
secure_vector<uint8_t> checksum(BS);
// fold checksum
- for(size_t i = 0; i != m_checksum.size(); ++i)
- checksum[i % checksum.size()] ^= m_checksum[i];
+ for(size_t i = 0; i != m_checksum.size(); i += BS)
+ {
+ xor_buf(checksum.data(), m_checksum.data() + i, BS);
+ }
// compute the mac
secure_vector<uint8_t> mac = m_offset;
diff --git a/src/lib/modes/aead/ocb/ocb.h b/src/lib/modes/aead/ocb/ocb.h
index 4188e8574..f4a54ee30 100644
--- a/src/lib/modes/aead/ocb/ocb.h
+++ b/src/lib/modes/aead/ocb/ocb.h
@@ -55,6 +55,10 @@ class BOTAN_PUBLIC_API(2,0) OCB_Mode : public AEAD_Mode
*/
OCB_Mode(BlockCipher* cipher, size_t tag_size);
+ size_t block_size() const { return m_block_size; }
+ size_t par_blocks() const { return m_par_blocks; }
+ size_t par_bytes() const { return m_checksum.size(); }
+
// fixme make these private
std::unique_ptr<BlockCipher> m_cipher;
std::unique_ptr<L_computer> m_L;
@@ -71,7 +75,9 @@ class BOTAN_PUBLIC_API(2,0) OCB_Mode : public AEAD_Mode
secure_vector<uint8_t> update_nonce(const uint8_t nonce[], size_t nonce_len);
- const size_t m_tag_size = 0;
+ const size_t m_tag_size;
+ const size_t m_block_size;
+ const size_t m_par_blocks;
secure_vector<uint8_t> m_last_nonce;
secure_vector<uint8_t> m_stretch;
};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-22 11:53:09 +0000