8#include <botan/internal/rc4.h>
9#include <botan/exceptn.h>
16void RC4::cipher_bytes(
const uint8_t in[], uint8_t out[],
size_t length)
20 while(length >= m_buffer.size() - m_position)
22 xor_buf(out, in, &m_buffer[m_position], m_buffer.size() - m_position);
23 length -= (m_buffer.size() - m_position);
24 in += (m_buffer.size() - m_position);
25 out += (m_buffer.size() - m_position);
28 xor_buf(out, in, &m_buffer[m_position], length);
34 return std::make_unique<RC4>(m_SKIP);
47void RC4::set_iv_bytes(
const uint8_t* ,
size_t length)
59 for(
size_t i = 0; i != m_buffer.size(); i += 4)
61 SX = m_state[m_X+1]; m_Y = (m_Y + SX) % 256; SY = m_state[m_Y];
62 m_state[m_X+1] = SY; m_state[m_Y] = SX;
63 m_buffer[i] = m_state[(SX + SY) % 256];
65 SX = m_state[m_X+2]; m_Y = (m_Y + SX) % 256; SY = m_state[m_Y];
66 m_state[m_X+2] = SY; m_state[m_Y] = SX;
67 m_buffer[i+1] = m_state[(SX + SY) % 256];
69 SX = m_state[m_X+3]; m_Y = (m_Y + SX) % 256; SY = m_state[m_Y];
70 m_state[m_X+3] = SY; m_state[m_Y] = SX;
71 m_buffer[i+2] = m_state[(SX + SY) % 256];
73 m_X = (m_X + 4) % 256;
74 SX = m_state[m_X]; m_Y = (m_Y + SX) % 256; SY = m_state[m_Y];
75 m_state[m_X] = SY; m_state[m_Y] = SX;
76 m_buffer[i+3] = m_state[(SX + SY) % 256];
83 return !m_state.empty();
89void RC4::key_schedule(
const uint8_t key[],
size_t length)
94 m_position = m_X = m_Y = 0;
96 for(
size_t i = 0; i != 256; ++i)
97 m_state[i] =
static_cast<uint8_t
>(i);
99 for(
size_t i = 0, state_index = 0; i != 256; ++i)
101 state_index = (state_index + key[i % length] + m_state[i]) % 256;
102 std::swap(m_state[i], m_state[state_index]);
105 for(
size_t i = 0; i <= m_SKIP; i += m_buffer.size())
108 m_position += (m_SKIP % m_buffer.size());
118 else if(m_SKIP == 256)
121 return "RC4(" + std::to_string(m_SKIP) +
")";
131 m_position = m_X = m_Y = 0;
Key_Length_Specification key_spec() const override
std::string name() const override
std::unique_ptr< StreamCipher > new_object() const override
size_t buffer_size() const override
void seek(uint64_t offset) override
bool has_keying_material() const override
void assert_key_material_set() const
void zap(std::vector< T, Alloc > &vec)
void xor_buf(uint8_t out[], const uint8_t in[], size_t length)