Added support for A5/2, A5/3, A5/4. Issue #85
diff --git a/lib/decryption/decryption_impl.cc b/lib/decryption/decryption_impl.cc
index 836d9d2..9e6112b 100644
--- a/lib/decryption/decryption_impl.cc
+++ b/lib/decryption/decryption_impl.cc
@@ -25,6 +25,7 @@
#include <gnuradio/io_signature.h>
#include <grgsm/gsmtap.h>
#include <grgsm/endian.h>
+#include <numeric>
#include "decryption_impl.h"
extern "C" {
@@ -37,21 +38,24 @@
namespace gsm {
decryption::sptr
- decryption::make(const std::vector<uint8_t> & k_c)
+ decryption::make(const std::vector<uint8_t> & k_c, unsigned int a5_version)
{
return gnuradio::get_initial_sptr
- (new decryption_impl(k_c));
+ (new decryption_impl(k_c, a5_version));
}
/*
* The private constructor
*/
- decryption_impl::decryption_impl(const std::vector<uint8_t> & k_c)
+ decryption_impl::decryption_impl(const std::vector<uint8_t> & k_c, unsigned int a5_version)
: gr::block("decryption",
gr::io_signature::make(0, 0, 0),
- gr::io_signature::make(0, 0, 0))
+ gr::io_signature::make(0, 0, 0)),
+ d_k_c_valid(false)
{
set_k_c(k_c);
+ set_a5_version(a5_version);
+ validate_k_c();
// std::cout << "Be careful with decryption block - it wasn't tested yet!" << std::endl;
message_port_register_in(pmt::mp("bursts"));
@@ -68,29 +72,50 @@
void decryption_impl::set_k_c(const std::vector<uint8_t> & k_c)
{
- if (k_c.size() == 8)
+ d_k_c = k_c;
+ }
+
+ void decryption_impl::set_a5_version(unsigned int a5_version)
+ {
+ d_a5_version = 1;
+ if (a5_version >= 1 && a5_version <= 4)
{
- for (int i=0; i<8; i++)
- {
- d_k_c[i] = k_c[i];
- }
+ d_a5_version = a5_version;
+ }
+ }
+
+ void decryption_impl::validate_k_c()
+ {
+ if (d_k_c.size() == 0)
+ {
+ d_k_c_valid = false;
+ return;
+ }
+ else if ((d_a5_version < 4 && d_k_c.size() != 8) || (d_a5_version == 4 && d_k_c.size() != 16))
+ {
+ d_k_c_valid = false;
+ return;
}
else
{
- for (int i=0; i<8; i++)
+ for (int i=0; i<d_k_c.size(); i++)
{
- d_k_c[i] = 0;
+ if (d_k_c[i] != 0)
+ {
+ d_k_c_valid = true;
+ return;
+ }
}
}
}
void decryption_impl::decrypt(pmt::pmt_t msg)
{
- if(d_k_c[0] == 0 && d_k_c[1] == 0 && d_k_c[2] == 0 && d_k_c[3] == 0 &
- d_k_c[4] == 0 && d_k_c[5] == 0 && d_k_c[6] == 0 && d_k_c[7] == 0)
+ if (!d_k_c_valid)
{
message_port_pub(pmt::mp("bursts"), msg);
- } else
+ }
+ else
{
uint8_t decrypted_data[BURST_SIZE];
uint8_t keystream[114];
@@ -104,10 +129,10 @@
if(uplink_burst){
//process uplink burst
- osmo_a5(1, d_k_c, frame_number, NULL, keystream);
+ osmo_a5(d_a5_version, &d_k_c[0], frame_number, NULL, keystream);
} else {
//process downlink burst
- osmo_a5(1, d_k_c, frame_number, keystream, NULL);
+ osmo_a5(d_a5_version, &d_k_c[0], frame_number, keystream, NULL);
}
/* guard bits */
for (int i = 0; i < 3; i++) {