From 62bed3663884ebee3b0784b063320235b20d49f8 Mon Sep 17 00:00:00 2001
From: Fist0urs <eddy.maaalou@gmail.com>
Date: Fri, 19 Feb 2016 23:12:46 +0100
Subject: [PATCH] Add verification of checksum for -m 13100 This avoid
 collisions by arc4'ing all data then hmac-md5 when valid ASN1 structures
 headers are found. Performance should not be impacted.

---
 OpenCL/m13100_a0.cl | 314 ++++++++++++++++++++++++++++++++++++++------
 OpenCL/m13100_a1.cl | 259 ++++++++++++++++++++++++++++++------
 OpenCL/m13100_a3.cl | 251 +++++++++++++++++++++++++++++------
 src/shared.c        |  11 +-
 tools/test.pl       |   2 +-
 5 files changed, 710 insertions(+), 127 deletions(-)

diff --git a/OpenCL/m13100_a0.cl b/OpenCL/m13100_a0.cl
index 050b316ad..8ea9db59f 100644
--- a/OpenCL/m13100_a0.cl
+++ b/OpenCL/m13100_a0.cl
@@ -1,7 +1,7 @@
 /**
  * Authors......: Jens Steube <jens.steube@gmail.com>
- * Authors......: Fist0urs   <eddy.maaalou@gmail.com>
-
+ * Authors......: Fist0urs <eddy.maaalou@gmail.com>
+ *
  * License.....: MIT
  */
 
@@ -140,40 +140,6 @@ static u8 rc4_next_16 (__local RC4_KEY *rc4_key, u8 i, u8 j, __global u32 in[4],
   return j;
 }
 
-static int decrypt_and_check (__local RC4_KEY *rc4_key, u32 data[4], __global u32* edata2)
-{
-  rc4_init_16 (rc4_key, data);
-
-  u32 out[8];
-
-  u8 j = 0;
-
-  /* 
-    8 first bytes are nonce, then ASN1 structs (DER encoding: type-length-data)
-
-    if length >= 128 bytes:
-        length is on 2 bytes and type is \x63\x82 (encode_krb5_enc_tkt_part) and data is an ASN1 sequence \x30\x82
-    else:
-        length is on 1 byte and type is \x63\x81 and data is an ASN1 sequence \x30\x81
-
-    next headers follow the same ASN1 "type-length-data" scheme
-  */
-
-  j = rc4_next_16 (rc4_key,  0, 0, edata2, out);
-
-  if (((out[2] & 0xff00ffff) != 0x30008163) && ((out[2] & 0x0000ffff) != 0x00008263)) return 0;
-
-  j = rc4_next_16 (rc4_key,  16, j, edata2 + 4, out + 4);
-
-  if (((out[4] & 0x00ffffff) != 0x00000503) && (out[4] != 0x050307A0)) return 0;
-
-  // TODO (or not): add RC4'ing of all edata2 then hmac-md5 and compare with 
-  // checksum to be definitely sure that this is the correct pass (even if 
-  // collisions must be very rare)
-
-  return 1;
-}
-
 static void md4_transform (const u32 w0[4], const u32 w1[4], const u32 w2[4], const u32 w3[4], u32 digest[4])
 {
   u32 a = digest[0];
@@ -421,8 +387,207 @@ static void hmac_md5_run (u32 w0[4], u32 w1[4], u32 w2[4], u32 w3[4], u32 ipad[4
   md5_transform (w0, w1, w2, w3, digest);
 }
 
+static int decrypt_and_check (__local RC4_KEY *rc4_key, u32 data[4], __global u32 *edata2, const u32 edata2_len, const u32 K2[4], const u32 checksum[4])
+{
+  rc4_init_16 (rc4_key, data);
 
-static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, const u32 checksum[4], u32 digest[4])
+  u32 out0[4];
+  u32 out1[4];
+
+  u8 i = 0;
+  u8 j = 0;
+
+  /*
+    8 first bytes are nonce, then ASN1 structs (DER encoding: type-length-data)
+
+    if length >= 128 bytes:
+        length is on 2 bytes and type is \x63\x82 (encode_krb5_enc_tkt_part) and data is an ASN1 sequence \x30\x82
+    else:
+        length is on 1 byte and type is \x63\x81 and data is an ASN1 sequence \x30\x81
+
+    next headers follow the same ASN1 "type-length-data" scheme
+  */
+
+  j = rc4_next_16 (rc4_key, i, j, edata2 + 0, out0); i += 16;
+
+  if (((out0[2] & 0xff00ffff) != 0x30008163) && ((out0[2] & 0x0000ffff) != 0x00008263)) return 0;
+
+  j = rc4_next_16 (rc4_key, i, j, edata2 + 4, out1); i += 16;
+
+  if (((out1[0] & 0x00ffffff) != 0x00000503) && (out1[0] != 0x050307A0)) return 0;
+
+  rc4_init_16 (rc4_key, data);
+
+  i = 0;
+  j = 0;
+
+  // init hmac
+
+  u32 w0[4];
+  u32 w1[4];
+  u32 w2[4];
+  u32 w3[4];
+
+  w0[0] = K2[0];
+  w0[1] = K2[1];
+  w0[2] = K2[2];
+  w0[3] = K2[3];
+  w1[0] = 0;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = 0;
+  w3[3] = 0;
+
+  u32 ipad[4];
+  u32 opad[4];
+
+  hmac_md5_pad (w0, w1, w2, w3, ipad, opad);
+
+  int edata2_left;
+
+  for (edata2_left = edata2_len; edata2_left >= 64; edata2_left -= 64)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w3); i += 16; edata2 += 4;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+
+  w0[0] = 0;
+  w0[1] = 0;
+  w0[2] = 0;
+  w0[3] = 0;
+  w1[0] = 0;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = 0;
+  w3[3] = 0;
+
+  if (edata2_left < 16)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+
+    truncate_block  (w0, edata2_left & 0xf);
+    append_0x80_1x4 (w0, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else if (edata2_left < 32)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+
+    truncate_block  (w1, edata2_left & 0xf);
+    append_0x80_1x4 (w1, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else if (edata2_left < 48)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+
+    truncate_block  (w2, edata2_left & 0xf);
+    append_0x80_1x4 (w2, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w3); i += 16; edata2 += 4;
+
+    truncate_block  (w3, edata2_left & 0xf);
+    append_0x80_1x4 (w3, edata2_left & 0xf);
+
+    if (edata2_left < 56)
+    {
+      w3[2] = (64 + edata2_len) * 8;
+      w3[3] = 0;
+
+      md5_transform (w0, w1, w2, w3, ipad);
+    }
+    else
+    {
+      md5_transform (w0, w1, w2, w3, ipad);
+
+      w0[0] = 0;
+      w0[1] = 0;
+      w0[2] = 0;
+      w0[3] = 0;
+      w1[0] = 0;
+      w1[1] = 0;
+      w1[2] = 0;
+      w1[3] = 0;
+      w2[0] = 0;
+      w2[1] = 0;
+      w2[2] = 0;
+      w2[3] = 0;
+      w3[0] = 0;
+      w3[1] = 0;
+      w3[2] = (64 + edata2_len) * 8;
+      w3[3] = 0;
+
+      md5_transform (w0, w1, w2, w3, ipad);
+    }
+  }
+
+  w0[0] = ipad[0];
+  w0[1] = ipad[1];
+  w0[2] = ipad[2];
+  w0[3] = ipad[3];
+  w1[0] = 0x80;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = (64 + 16) * 8;
+  w3[3] = 0;
+
+  md5_transform (w0, w1, w2, w3, opad);
+
+  if (checksum[0] != opad[0]) return 0;
+  if (checksum[1] != opad[1]) return 0;
+  if (checksum[2] != opad[2]) return 0;
+  if (checksum[3] != opad[3]) return 0;
+
+  return 1;
+}
+
+static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, const u32 checksum[4], u32 digest[4], u32 K2[4])
 {
   /**
    * pads
@@ -510,7 +675,14 @@ static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, co
 
   hmac_md5_run (w0_t, w1_t, w2_t, w3_t, ipad, opad, digest);
 
-  // K3=MD5_HMAC(K1,checksum);  
+  // K2 = K1;
+
+  K2[0] = digest[0];
+  K2[1] = digest[1];
+  K2[2] = digest[2];
+  K2[3] = digest[3];
+
+  // K3=MD5_HMAC(K1,checksum);
 
   w0_t[0] = digest[0];
   w0_t[1] = digest[1];
@@ -551,6 +723,60 @@ static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, co
   hmac_md5_run (w0_t, w1_t, w2_t, w3_t, ipad, opad, digest);
 }
 
+static void m13100 (__local RC4_KEY *rc4_keys, u32 w0[4], u32 w1[4], u32 w2[4], u32 w3[4], const u32 pw_len, __global pw_t *pws, __global kernel_rule_t *rules_buf, __global comb_t *combs_buf, __global bf_t *bfs_buf, __global void *tmps, __global void *hooks, __global u32 *bitmaps_buf_s1_a, __global u32 *bitmaps_buf_s1_b, __global u32 *bitmaps_buf_s1_c, __global u32 *bitmaps_buf_s1_d, __global u32 *bitmaps_buf_s2_a, __global u32 *bitmaps_buf_s2_b, __global u32 *bitmaps_buf_s2_c, __global u32 *bitmaps_buf_s2_d, __global plain_t *plains_buf, __global digest_t *digests_buf, __global u32 *hashes_shown, __global salt_t *salt_bufs, __global krb5tgs_t *krb5tgs_bufs, __global u32 *d_return_buf, __global u32 *d_scryptV_buf, const u32 bitmap_mask, const u32 bitmap_shift1, const u32 bitmap_shift2, const u32 salt_pos, const u32 loop_pos, const u32 loop_cnt, const u32 bfs_cnt, const u32 digests_cnt, const u32 digests_offset)
+{
+  /**
+   * modifier
+   */
+
+  const u32 gid = get_global_id (0);
+  const u32 lid = get_local_id (0);
+
+  /**
+   * salt
+   */
+
+  u32 checksum[4];
+
+  checksum[0] = krb5tgs_bufs[salt_pos].checksum[0];
+  checksum[1] = krb5tgs_bufs[salt_pos].checksum[1];
+  checksum[2] = krb5tgs_bufs[salt_pos].checksum[2];
+  checksum[3] = krb5tgs_bufs[salt_pos].checksum[3];
+
+  /**
+   * loop
+   */
+
+  u32 w0l = w0[0];
+
+  for (u32 il_pos = 0; il_pos < bfs_cnt; il_pos++)
+  {
+    const u32 w0r = bfs_buf[il_pos].i;
+
+    w0[0] = w0l | w0r;
+
+    u32 digest[4];
+
+    u32 K2[4];
+
+    kerb_prepare (w0, w1, pw_len, checksum, digest, K2);
+
+    u32 tmp[4];
+
+    tmp[0] = digest[0];
+    tmp[1] = digest[1];
+    tmp[2] = digest[2];
+    tmp[3] = digest[3];
+
+    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2, krb5tgs_bufs[salt_pos].edata2_len, K2, checksum) == 1)
+    {
+      mark_hash (plains_buf, hashes_shown, digests_offset, gid, il_pos);
+
+      d_return_buf[lid] = 1;
+    }
+  }
+}
+
 __kernel void m13100_m04 (__global pw_t *pws, __global kernel_rule_t *rules_buf, __global comb_t *combs_buf, __global bf_t *bfs_buf, __global void *tmps, __global void *hooks, __global u32 *bitmaps_buf_s1_a, __global u32 *bitmaps_buf_s1_b, __global u32 *bitmaps_buf_s1_c, __global u32 *bitmaps_buf_s1_d, __global u32 *bitmaps_buf_s2_a, __global u32 *bitmaps_buf_s2_b, __global u32 *bitmaps_buf_s2_c, __global u32 *bitmaps_buf_s2_d, __global plain_t *plains_buf, __global digest_t *digests_buf, __global u32 *hashes_shown, __global salt_t *salt_bufs, __global krb5tgs_t *krb5tgs_bufs, __global u32 *d_return_buf, __global u32 *d_scryptV_buf, const u32 bitmap_mask, const u32 bitmap_shift1, const u32 bitmap_shift2, const u32 salt_pos, const u32 loop_pos, const u32 loop_cnt, const u32 rules_cnt, const u32 digests_cnt, const u32 digests_offset, const u32 combs_mode, const u32 gid_max)
 {
   /**
@@ -637,7 +863,9 @@ __kernel void m13100_m04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
 
     u32 digest[4];
 
-    kerb_prepare (w0, w1, out_len, checksum, digest);
+    u32 K2[4];
+
+    kerb_prepare (w0, w1, pw_len, checksum, digest, K2);
 
     u32 tmp[4];
 
@@ -646,7 +874,7 @@ __kernel void m13100_m04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
     tmp[2] = digest[2];
     tmp[3] = digest[3];
 
-    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2) == 1)
+    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2, krb5tgs_bufs[salt_pos].edata2_len, K2, checksum) == 1)
     {
       mark_hash (plains_buf, hashes_shown, digests_offset, gid, il_pos);
 
@@ -749,7 +977,9 @@ __kernel void m13100_s04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
 
     u32 digest[4];
 
-    kerb_prepare (w0, w1, out_len, checksum, digest);
+    u32 K2[4];
+
+    kerb_prepare (w0, w1, pw_len, checksum, digest, K2);
 
     u32 tmp[4];
 
@@ -758,7 +988,7 @@ __kernel void m13100_s04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
     tmp[2] = digest[2];
     tmp[3] = digest[3];
 
-    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2) == 1)
+    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2, krb5tgs_bufs[salt_pos].edata2_len, K2, checksum) == 1)
     {
       mark_hash (plains_buf, hashes_shown, digests_offset, gid, il_pos);
 
diff --git a/OpenCL/m13100_a1.cl b/OpenCL/m13100_a1.cl
index 86293b310..858ea01e4 100644
--- a/OpenCL/m13100_a1.cl
+++ b/OpenCL/m13100_a1.cl
@@ -1,7 +1,7 @@
 /**
  * Authors......: Jens Steube <jens.steube@gmail.com>
- * Authors......: Fist0urs   <eddy.maaalou@gmail.com>
-
+ * Authors......: Fist0urs <eddy.maaalou@gmail.com>
+ *
  * License.....: MIT
  */
 
@@ -138,40 +138,6 @@ static u8 rc4_next_16 (__local RC4_KEY *rc4_key, u8 i, u8 j, __global u32 in[4],
   return j;
 }
 
-static int decrypt_and_check (__local RC4_KEY *rc4_key, u32 data[4], __global u32* edata2)
-{
-  rc4_init_16 (rc4_key, data);
-
-  u32 out[8];
-
-  u8 j = 0;
-
-  /* 
-    8 first bytes are nonce, then ASN1 structs (DER encoding: type-length-data)
-
-    if length >= 128 bytes:
-        length is on 2 bytes and type is \x63\x82 (encode_krb5_enc_tkt_part) and data is an ASN1 sequence \x30\x82
-    else:
-        length is on 1 byte and type is \x63\x81 and data is an ASN1 sequence \x30\x81
-
-    next headers follow the same ASN1 "type-length-data" scheme
-  */
-
-  j = rc4_next_16 (rc4_key,  0, 0, edata2, out);
-
-  if (((out[2] & 0xff00ffff) != 0x30008163) && ((out[2] & 0x0000ffff) != 0x00008263)) return 0;
-
-  j = rc4_next_16 (rc4_key,  16, j, edata2 + 4, out + 4);
-
-  if (((out[4] & 0x00ffffff) != 0x00000503) && (out[4] != 0x050307A0)) return 0;
-
-  // TODO (or not): add RC4'ing of all edata2 then hmac-md5 and compare with 
-  // checksum to be definitely sure that this is the correct pass (even if 
-  // collisions must be very rare)
-
-  return 1;
-}
-
 static void md4_transform (const u32 w0[4], const u32 w1[4], const u32 w2[4], const u32 w3[4], u32 digest[4])
 {
   u32 a = digest[0];
@@ -419,7 +385,207 @@ static void hmac_md5_run (u32 w0[4], u32 w1[4], u32 w2[4], u32 w3[4], u32 ipad[4
   md5_transform (w0, w1, w2, w3, digest);
 }
 
-static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, const u32 checksum[4], u32 digest[4])
+static int decrypt_and_check (__local RC4_KEY *rc4_key, u32 data[4], __global u32 *edata2, const u32 edata2_len, const u32 K2[4], const u32 checksum[4])
+{
+  rc4_init_16 (rc4_key, data);
+
+  u32 out0[4];
+  u32 out1[4];
+
+  u8 i = 0;
+  u8 j = 0;
+
+  /*
+    8 first bytes are nonce, then ASN1 structs (DER encoding: type-length-data)
+
+    if length >= 128 bytes:
+        length is on 2 bytes and type is \x63\x82 (encode_krb5_enc_tkt_part) and data is an ASN1 sequence \x30\x82
+    else:
+        length is on 1 byte and type is \x63\x81 and data is an ASN1 sequence \x30\x81
+
+    next headers follow the same ASN1 "type-length-data" scheme
+  */
+
+  j = rc4_next_16 (rc4_key, i, j, edata2 + 0, out0); i += 16;
+
+  if (((out0[2] & 0xff00ffff) != 0x30008163) && ((out0[2] & 0x0000ffff) != 0x00008263)) return 0;
+
+  j = rc4_next_16 (rc4_key, i, j, edata2 + 4, out1); i += 16;
+
+  if (((out1[0] & 0x00ffffff) != 0x00000503) && (out1[0] != 0x050307A0)) return 0;
+
+  rc4_init_16 (rc4_key, data);
+
+  i = 0;
+  j = 0;
+
+  // init hmac
+
+  u32 w0[4];
+  u32 w1[4];
+  u32 w2[4];
+  u32 w3[4];
+
+  w0[0] = K2[0];
+  w0[1] = K2[1];
+  w0[2] = K2[2];
+  w0[3] = K2[3];
+  w1[0] = 0;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = 0;
+  w3[3] = 0;
+
+  u32 ipad[4];
+  u32 opad[4];
+
+  hmac_md5_pad (w0, w1, w2, w3, ipad, opad);
+
+  int edata2_left;
+
+  for (edata2_left = edata2_len; edata2_left >= 64; edata2_left -= 64)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w3); i += 16; edata2 += 4;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+
+  w0[0] = 0;
+  w0[1] = 0;
+  w0[2] = 0;
+  w0[3] = 0;
+  w1[0] = 0;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = 0;
+  w3[3] = 0;
+
+  if (edata2_left < 16)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+
+    truncate_block  (w0, edata2_left & 0xf);
+    append_0x80_1x4 (w0, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else if (edata2_left < 32)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+
+    truncate_block  (w1, edata2_left & 0xf);
+    append_0x80_1x4 (w1, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else if (edata2_left < 48)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+
+    truncate_block  (w2, edata2_left & 0xf);
+    append_0x80_1x4 (w2, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w3); i += 16; edata2 += 4;
+
+    truncate_block  (w3, edata2_left & 0xf);
+    append_0x80_1x4 (w3, edata2_left & 0xf);
+
+    if (edata2_left < 56)
+    {
+      w3[2] = (64 + edata2_len) * 8;
+      w3[3] = 0;
+
+      md5_transform (w0, w1, w2, w3, ipad);
+    }
+    else
+    {
+      md5_transform (w0, w1, w2, w3, ipad);
+
+      w0[0] = 0;
+      w0[1] = 0;
+      w0[2] = 0;
+      w0[3] = 0;
+      w1[0] = 0;
+      w1[1] = 0;
+      w1[2] = 0;
+      w1[3] = 0;
+      w2[0] = 0;
+      w2[1] = 0;
+      w2[2] = 0;
+      w2[3] = 0;
+      w3[0] = 0;
+      w3[1] = 0;
+      w3[2] = (64 + edata2_len) * 8;
+      w3[3] = 0;
+
+      md5_transform (w0, w1, w2, w3, ipad);
+    }
+  }
+
+  w0[0] = ipad[0];
+  w0[1] = ipad[1];
+  w0[2] = ipad[2];
+  w0[3] = ipad[3];
+  w1[0] = 0x80;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = (64 + 16) * 8;
+  w3[3] = 0;
+
+  md5_transform (w0, w1, w2, w3, opad);
+
+  if (checksum[0] != opad[0]) return 0;
+  if (checksum[1] != opad[1]) return 0;
+  if (checksum[2] != opad[2]) return 0;
+  if (checksum[3] != opad[3]) return 0;
+
+  return 1;
+}
+
+static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, const u32 checksum[4], u32 digest[4], u32 K2[4])
 {
   /**
    * pads
@@ -507,6 +673,13 @@ static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, co
 
   hmac_md5_run (w0_t, w1_t, w2_t, w3_t, ipad, opad, digest);
 
+  // K2 = K1;
+
+  K2[0] = digest[0];
+  K2[1] = digest[1];
+  K2[2] = digest[2];
+  K2[3] = digest[3];
+
   // K3=MD5_HMAC(K1,checksum);
 
   w0_t[0] = digest[0];
@@ -688,7 +861,9 @@ __kernel void m13100_m04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
 
     u32 digest[4];
 
-    kerb_prepare (w0, w1, pw_len, checksum, digest);
+    u32 K2[4];
+
+    kerb_prepare (w0, w1, pw_len, checksum, digest, K2);
 
     u32 tmp[4];
 
@@ -697,7 +872,7 @@ __kernel void m13100_m04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
     tmp[2] = digest[2];
     tmp[3] = digest[3];
 
-    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2) == 1)
+    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2, krb5tgs_bufs[salt_pos].edata2_len, K2, checksum) == 1)
     {
       mark_hash (plains_buf, hashes_shown, digests_offset, gid, il_pos);
 
@@ -854,7 +1029,9 @@ __kernel void m13100_s04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
 
     u32 digest[4];
 
-    kerb_prepare (w0, w1, pw_len, checksum, digest);
+    u32 K2[4];
+
+    kerb_prepare (w0, w1, pw_len, checksum, digest, K2);
 
     u32 tmp[4];
 
@@ -863,7 +1040,7 @@ __kernel void m13100_s04 (__global pw_t *pws, __global kernel_rule_t *rules_buf,
     tmp[2] = digest[2];
     tmp[3] = digest[3];
 
-    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2) == 1)
+    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2, krb5tgs_bufs[salt_pos].edata2_len, K2, checksum) == 1)
     {
       mark_hash (plains_buf, hashes_shown, digests_offset, gid, il_pos);
 
diff --git a/OpenCL/m13100_a3.cl b/OpenCL/m13100_a3.cl
index 159631dc7..495cb9e7c 100644
--- a/OpenCL/m13100_a3.cl
+++ b/OpenCL/m13100_a3.cl
@@ -1,6 +1,6 @@
 /**
  * Authors......: Jens Steube <jens.steube@gmail.com>
- * Authors......: Fist0urs   <eddy.maaalou@gmail.com>
+ * Authors......: Fist0urs <eddy.maaalou@gmail.com>
  *
  * License.....: MIT
  */
@@ -138,40 +138,6 @@ static u8 rc4_next_16 (__local RC4_KEY *rc4_key, u8 i, u8 j, __global u32 in[4],
   return j;
 }
 
-static int decrypt_and_check (__local RC4_KEY *rc4_key, u32 data[4], __global u32* edata2)
-{
-  rc4_init_16 (rc4_key, data);
-
-  u32 out[8];
-
-  u8 j = 0;
-
-  /* 
-    8 first bytes are nonce, then ASN1 structs (DER encoding: type-length-data)
-
-    if length >= 128 bytes:
-        length is on 2 bytes and type is \x63\x82 (encode_krb5_enc_tkt_part) and data is an ASN1 sequence \x30\x82
-    else:
-        length is on 1 byte and type is \x63\x81 and data is an ASN1 sequence \x30\x81
-
-    next headers follow the same ASN1 "type-length-data" scheme
-  */
-
-  j = rc4_next_16 (rc4_key,  0, 0, edata2, out);
-
-  if (((out[2] & 0xff00ffff) != 0x30008163) && ((out[2] & 0x0000ffff) != 0x00008263)) return 0;
-
-  j = rc4_next_16 (rc4_key,  16, j, edata2 + 4, out + 4);
-
-  if (((out[4] & 0x00ffffff) != 0x00000503) && (out[4] != 0x050307A0)) return 0;
-
-  // TODO (or not): add RC4'ing of all edata2 then hmac-md5 and compare with 
-  // checksum to be definitely sure that this is the correct pass (even if 
-  // collisions must be very rare)
-
-  return 1;
-}
-
 static void md4_transform (const u32 w0[4], const u32 w1[4], const u32 w2[4], const u32 w3[4], u32 digest[4])
 {
   u32 a = digest[0];
@@ -419,7 +385,207 @@ static void hmac_md5_run (u32 w0[4], u32 w1[4], u32 w2[4], u32 w3[4], u32 ipad[4
   md5_transform (w0, w1, w2, w3, digest);
 }
 
-static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, const u32 checksum[4], u32 digest[4])
+static int decrypt_and_check (__local RC4_KEY *rc4_key, u32 data[4], __global u32 *edata2, const u32 edata2_len, const u32 K2[4], const u32 checksum[4])
+{
+  rc4_init_16 (rc4_key, data);
+
+  u32 out0[4];
+  u32 out1[4];
+
+  u8 i = 0;
+  u8 j = 0;
+
+  /*
+    8 first bytes are nonce, then ASN1 structs (DER encoding: type-length-data)
+
+    if length >= 128 bytes:
+        length is on 2 bytes and type is \x63\x82 (encode_krb5_enc_tkt_part) and data is an ASN1 sequence \x30\x82
+    else:
+        length is on 1 byte and type is \x63\x81 and data is an ASN1 sequence \x30\x81
+
+    next headers follow the same ASN1 "type-length-data" scheme
+  */
+
+  j = rc4_next_16 (rc4_key, i, j, edata2 + 0, out0); i += 16;
+
+  if (((out0[2] & 0xff00ffff) != 0x30008163) && ((out0[2] & 0x0000ffff) != 0x00008263)) return 0;
+
+  j = rc4_next_16 (rc4_key, i, j, edata2 + 4, out1); i += 16;
+
+  if (((out1[0] & 0x00ffffff) != 0x00000503) && (out1[0] != 0x050307A0)) return 0;
+
+  rc4_init_16 (rc4_key, data);
+
+  i = 0;
+  j = 0;
+
+  // init hmac
+
+  u32 w0[4];
+  u32 w1[4];
+  u32 w2[4];
+  u32 w3[4];
+
+  w0[0] = K2[0];
+  w0[1] = K2[1];
+  w0[2] = K2[2];
+  w0[3] = K2[3];
+  w1[0] = 0;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = 0;
+  w3[3] = 0;
+
+  u32 ipad[4];
+  u32 opad[4];
+
+  hmac_md5_pad (w0, w1, w2, w3, ipad, opad);
+
+  int edata2_left;
+
+  for (edata2_left = edata2_len; edata2_left >= 64; edata2_left -= 64)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w3); i += 16; edata2 += 4;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+
+  w0[0] = 0;
+  w0[1] = 0;
+  w0[2] = 0;
+  w0[3] = 0;
+  w1[0] = 0;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = 0;
+  w3[3] = 0;
+
+  if (edata2_left < 16)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+
+    truncate_block  (w0, edata2_left & 0xf);
+    append_0x80_1x4 (w0, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else if (edata2_left < 32)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+
+    truncate_block  (w1, edata2_left & 0xf);
+    append_0x80_1x4 (w1, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else if (edata2_left < 48)
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+
+    truncate_block  (w2, edata2_left & 0xf);
+    append_0x80_1x4 (w2, edata2_left & 0xf);
+
+    w3[2] = (64 + edata2_len) * 8;
+    w3[3] = 0;
+
+    md5_transform (w0, w1, w2, w3, ipad);
+  }
+  else
+  {
+    j = rc4_next_16 (rc4_key, i, j, edata2, w0); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w1); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w2); i += 16; edata2 += 4;
+    j = rc4_next_16 (rc4_key, i, j, edata2, w3); i += 16; edata2 += 4;
+
+    truncate_block  (w3, edata2_left & 0xf);
+    append_0x80_1x4 (w3, edata2_left & 0xf);
+
+    if (edata2_left < 56)
+    {
+      w3[2] = (64 + edata2_len) * 8;
+      w3[3] = 0;
+
+      md5_transform (w0, w1, w2, w3, ipad);
+    }
+    else
+    {
+      md5_transform (w0, w1, w2, w3, ipad);
+
+      w0[0] = 0;
+      w0[1] = 0;
+      w0[2] = 0;
+      w0[3] = 0;
+      w1[0] = 0;
+      w1[1] = 0;
+      w1[2] = 0;
+      w1[3] = 0;
+      w2[0] = 0;
+      w2[1] = 0;
+      w2[2] = 0;
+      w2[3] = 0;
+      w3[0] = 0;
+      w3[1] = 0;
+      w3[2] = (64 + edata2_len) * 8;
+      w3[3] = 0;
+
+      md5_transform (w0, w1, w2, w3, ipad);
+    }
+  }
+
+  w0[0] = ipad[0];
+  w0[1] = ipad[1];
+  w0[2] = ipad[2];
+  w0[3] = ipad[3];
+  w1[0] = 0x80;
+  w1[1] = 0;
+  w1[2] = 0;
+  w1[3] = 0;
+  w2[0] = 0;
+  w2[1] = 0;
+  w2[2] = 0;
+  w2[3] = 0;
+  w3[0] = 0;
+  w3[1] = 0;
+  w3[2] = (64 + 16) * 8;
+  w3[3] = 0;
+
+  md5_transform (w0, w1, w2, w3, opad);
+
+  if (checksum[0] != opad[0]) return 0;
+  if (checksum[1] != opad[1]) return 0;
+  if (checksum[2] != opad[2]) return 0;
+  if (checksum[3] != opad[3]) return 0;
+
+  return 1;
+}
+
+static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, const u32 checksum[4], u32 digest[4], u32 K2[4])
 {
   /**
    * pads
@@ -507,6 +673,13 @@ static void kerb_prepare (const u32 w0[4], const u32 w1[4], const u32 pw_len, co
 
   hmac_md5_run (w0_t, w1_t, w2_t, w3_t, ipad, opad, digest);
 
+  // K2 = K1;
+
+  K2[0] = digest[0];
+  K2[1] = digest[1];
+  K2[2] = digest[2];
+  K2[3] = digest[3];
+
   // K3=MD5_HMAC(K1,checksum);
 
   w0_t[0] = digest[0];
@@ -582,7 +755,9 @@ static void m13100 (__local RC4_KEY *rc4_keys, u32 w0[4], u32 w1[4], u32 w2[4],
 
     u32 digest[4];
 
-    kerb_prepare (w0, w1, pw_len, checksum, digest);
+    u32 K2[4];
+
+    kerb_prepare (w0, w1, pw_len, checksum, digest, K2);
 
     u32 tmp[4];
 
@@ -591,7 +766,7 @@ static void m13100 (__local RC4_KEY *rc4_keys, u32 w0[4], u32 w1[4], u32 w2[4],
     tmp[2] = digest[2];
     tmp[3] = digest[3];
 
-    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2) == 1)
+    if (decrypt_and_check (&rc4_keys[lid], tmp, krb5tgs_bufs[salt_pos].edata2, krb5tgs_bufs[salt_pos].edata2_len, K2, checksum) == 1)
     {
       mark_hash (plains_buf, hashes_shown, digests_offset, gid, il_pos);
 
diff --git a/src/shared.c b/src/shared.c
index 159275769..08bcd90ba 100644
--- a/src/shared.c
+++ b/src/shared.c
@@ -8302,7 +8302,7 @@ void ascii_digest (char out_buf[4096], uint salt_pos, uint digest_pos)
     u8 *ptr_checksum  = (u8 *) krb5tgs->checksum;
     u8 *ptr_edata2 = (u8 *) krb5tgs->edata2;
 
-    char data[256] = { 0 };
+    char data[2560 * 4 * 2] = { 0 };
 
     char *ptr_data = data;
 
@@ -8312,11 +8312,9 @@ void ascii_digest (char out_buf[4096], uint salt_pos, uint digest_pos)
     /* skip '$' */
     ptr_data++;
 
-    for (uint i = 0; i < 32; i++, ptr_data += 2)
+    for (uint i = 0; i < krb5tgs->edata2_len; i++, ptr_data += 2)
       sprintf (ptr_data, "%02x", ptr_edata2[i]);
 
-    *ptr_data = 0;
-
     snprintf (out_buf, len-1, "%s$%s$%s$%s",
       SIGNATURE_KRB5TGS,
       (char *) krb5tgs->account_info,
@@ -18795,7 +18793,10 @@ int krb5tgs_parse_hash (char *input_buf, uint input_len, hash_t *hash_buf)
                     | hex_convert (p0) << 4;
   }
 
-  krb5tgs->edata2_len = strlen (edata_ptr - input_len) / (2 * 4);
+ /* this is needed for hmac_md5 */
+  *edata_ptr++ = 0x80;
+  
+  krb5tgs->edata2_len = (data_len - 32) / 2 ;
 
   salt->salt_buf[0] = krb5tgs->checksum[0];
   salt->salt_buf[1] = krb5tgs->checksum[1];
diff --git a/tools/test.pl b/tools/test.pl
index 30df3ffcc..5d945fe0c 100755
--- a/tools/test.pl
+++ b/tools/test.pl
@@ -6704,7 +6704,7 @@ END_CODE
 
     my $edata2 = $cipher->RC4 (pack ("H*", $cleartext_ticket));
 
-    $tmp_hash = sprintf ('$krb5tgs$23$*%s$%s$%s*$%s$%s', $user, $realm, $spn, unpack ("H*", $checksum), substr (unpack ("H*", $edata2), 0, 64));
+    $tmp_hash = sprintf ('$krb5tgs$23$*%s$%s$%s*$%s$%s', $user, $realm, $spn, unpack ("H*", $checksum), unpack ("H*", $edata2));
   }
 
   return ($tmp_hash);