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Implement AES IGE encrypt using AES CBC.

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GitOrigin-RevId: ca803ca847a9c44e70687ade0f1ea25c0ee0ebb2
This commit is contained in:
levlam 2020-06-16 06:16:09 +03:00
parent 3442a88413
commit f3ebae267d
2 changed files with 45 additions and 1 deletions
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42
tdutils/td/utils/crypto.cpp
View File

@ -452,6 +452,7 @@ void aes_ige_decrypt(Slice aes_key, MutableSlice aes_iv, Slice from, MutableSlic
class AesIgeState::Impl {
public:
AesState cbc_state;
AesState state;
AesBlock encrypted_iv;
AesBlock plaintext_iv;
@ -463,6 +464,36 @@ class AesIgeState::Impl {
auto in = from.ubegin();
auto out = to.ubegin();
static constexpr size_t BLOCK_COUNT = 32;
while (len >= BLOCK_COUNT) {
AesBlock data[BLOCK_COUNT];
AesBlock data_xored[BLOCK_COUNT];
std::memcpy(data, in, sizeof(data));
data_xored[0] = data[0];
data_xored[1] = plaintext_iv ^ data[1];
for (size_t i = 2; i < BLOCK_COUNT; i++) {
data_xored[i] = data[i - 2] ^ data[i];
}
EVP_EncryptInit(cbc_state.impl_->ctx, nullptr, nullptr, encrypted_iv.raw());
int outlen = 0;
int inlen = static_cast<int>(sizeof(data_xored));
EVP_EncryptUpdate(cbc_state.impl_->ctx, data_xored[0].raw(), &outlen, data_xored[0].raw(), inlen);
CHECK(outlen == inlen);
data_xored[0] ^= plaintext_iv;
for (size_t i = 1; i < BLOCK_COUNT; i++) {
data_xored[i] ^= data[i - 1];
}
plaintext_iv = data[BLOCK_COUNT - 1];
encrypted_iv = data_xored[BLOCK_COUNT - 1];
std::memcpy(out, data_xored, sizeof(data_xored));
len -= BLOCK_COUNT;
in += AES_BLOCK_SIZE * BLOCK_COUNT;
out += AES_BLOCK_SIZE * BLOCK_COUNT;
}
AesBlock plaintext;
while (len) {
@ -517,6 +548,17 @@ void AesIgeState::init(Slice key, Slice iv, bool encrypt) {
impl_ = make_unique<Impl>();
}
impl_->state.init(key, encrypt);
if (encrypt) {
auto &impl = impl_->cbc_state.impl_;
if (!impl) {
impl = make_unique<AesState::Impl>();
impl->ctx = EVP_CIPHER_CTX_new();
}
int res = EVP_EncryptInit_ex(impl->ctx, EVP_aes_256_cbc(), nullptr, key.ubegin(), nullptr);
LOG_IF(FATAL, res != 1);
EVP_CIPHER_CTX_set_padding(impl->ctx, 0);
}
impl_->encrypted_iv.load(iv.ubegin());
impl_->plaintext_iv.load(iv.ubegin() + AES_BLOCK_SIZE);
}

4
tdutils/td/utils/crypto.h
View File

@ -37,6 +37,8 @@ class AesState {
private:
class Impl;
unique_ptr<Impl> impl_;
friend class AesIgeState;
};
int pq_factorize(Slice pq_str, string *p_str, string *q_str);
@ -44,7 +46,7 @@ int pq_factorize(Slice pq_str, string *p_str, string *q_str);
void aes_ige_encrypt(Slice aes_key, MutableSlice aes_iv, Slice from, MutableSlice to);
void aes_ige_decrypt(Slice aes_key, MutableSlice aes_iv, Slice from, MutableSlice to);
struct AesIgeState {
class AesIgeState {
public:
AesIgeState();
AesIgeState(const AesIgeState &from) = delete;