diff --git a/src/descrambler/tvhcsa.c b/src/descrambler/tvhcsa.c
new file mode 100644
index 00000000..e7aa1afd
--- /dev/null
+++ b/src/descrambler/tvhcsa.c
@@ -0,0 +1,181 @@
+/*
+ *  tvheadend - CSA wrapper
+ *  Copyright (C) 2013 Adam Sutton
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "tvhcsa.h"
+#include "input/mpegts.h"
+#include "input/mpegts/tsdemux.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+
+void
+tvhcsa_descramble
+  ( tvhcsa_t *csa, struct mpegts_service *s, struct elementary_stream *st,
+    const uint8_t *tsb, int cw_update_pending )
+{
+#if ENABLE_DVBCSA
+  uint8_t *pkt;
+  int xc0;
+  int ev_od;
+  int len;
+  int offset;
+  int n;
+  int i;
+  const uint8_t *t0;
+
+  pkt = csa->csa_tsbcluster + csa->csa_fill * 188;
+  memcpy(pkt, tsb, 188);
+  csa->csa_fill++;
+
+  do { // handle this packet
+    xc0 = pkt[3] & 0xc0;
+    if(xc0 == 0x00) { // clear
+      break;
+    }
+    if(xc0 == 0x40) { // reserved
+      break;
+    }
+    if(xc0 == 0x80 || xc0 == 0xc0) { // encrypted
+      ev_od = (xc0 & 0x40) >> 6; // 0 even, 1 odd
+      pkt[3] &= 0x3f;  // consider it decrypted now
+      if(pkt[3] & 0x20) { // incomplete packet
+        offset = 4 + pkt[4] + 1;
+        len = 188 - offset;
+        n = len >> 3;
+        // FIXME: //residue = len - (n << 3);
+        if(n == 0) { // decrypted==encrypted!
+          break; // this doesn't need more processing
+        }
+      } else {
+        len = 184;
+        offset = 4;
+        // FIXME: //n = 23;
+        // FIXME: //residue = 0;
+      }
+      if(ev_od == 0) {
+        csa->csa_tsbbatch_even[csa->csa_fill_even].data = pkt + offset;
+        csa->csa_tsbbatch_even[csa->csa_fill_even].len = len;
+        csa->csa_fill_even++;
+      } else {
+        csa->csa_tsbbatch_odd[csa->csa_fill_odd].data = pkt + offset;
+        csa->csa_tsbbatch_odd[csa->csa_fill_odd].len = len;
+        csa->csa_fill_odd++;
+      }
+    }
+  } while(0);
+
+  if(csa->csa_fill != csa->csa_cluster_size)
+    return;
+
+  if(csa->csa_fill_even) {
+    csa->csa_tsbbatch_even[csa->csa_fill_even].data = NULL;
+    dvbcsa_bs_decrypt(csa->csa_key_even, csa->csa_tsbbatch_even, 184);
+    csa->csa_fill_even = 0;
+  }
+  if(csa->csa_fill_odd) {
+    csa->csa_tsbbatch_odd[csa->csa_fill_odd].data = NULL;
+    dvbcsa_bs_decrypt(csa->csa_key_odd, csa->csa_tsbbatch_odd, 184);
+    csa->csa_fill_odd = 0;
+  }
+
+  t0 = csa->csa_tsbcluster;
+
+  for(i = 0; i < csa->csa_fill; i++) {
+	  ts_recv_packet2(s, t0);
+	  t0 += 188;
+  }
+  csa->csa_fill = 0;
+
+#else
+  int r;
+  unsigned char *vec[3];
+
+  memcpy(csa->csa_tsbcluster + csa->csa_fill * 188, tsb, 188);
+  csa->csa_fill++;
+
+  if(csa->csa_fill != csa->csa_cluster_size)
+    return;
+
+  while(1) {
+
+    vec[0] = csa->csa_tsbcluster;
+    vec[1] = csa->csa_tsbcluster + csa->csa_fill * 188;
+    vec[2] = NULL;
+    
+    r = decrypt_packets(csa->csa_keys, vec);
+    if(r > 0) {
+      int i;
+      const uint8_t *t0 = csa->csa_tsbcluster;
+
+      for(i = 0; i < r; i++) {
+	      ts_recv_packet2(s, t0);
+	      t0 += 188;
+      }
+
+      r = csa->csa_fill - r;
+      assert(r >= 0);
+
+      if(r > 0)
+	      memmove(csa->csa_tsbcluster, t0, r * 188);
+      csa->csa_fill = r;
+
+      if(cw_update_pending && r > 0)
+	      continue;
+    } else {
+      csa->csa_fill = 0;
+    }
+    break;
+  }
+#endif
+}
+
+void
+tvhcsa_init ( tvhcsa_t *csa )
+{
+#if ENABLE_DVBCSA
+  csa->csa_cluster_size  = dvbcsa_bs_batch_size();
+#else
+  csa->csa_cluster_size  = get_suggested_cluster_size();
+#endif
+  csa->csa_tsbcluster    = malloc(csa->csa_cluster_size * 188);
+#if ENABLE_DVBCSA
+  csa->csa_tsbbatch_even = malloc((csa->csa_cluster_size + 1) *
+                                   sizeof(struct dvbcsa_bs_batch_s));
+  csa->csa_tsbbatch_odd  = malloc((csa->csa_cluster_size + 1) *
+                                   sizeof(struct dvbcsa_bs_batch_s));
+  csa->csa_key_even      = dvbcsa_bs_key_alloc();
+  csa->csa_key_odd       = dvbcsa_bs_key_alloc();
+#else
+  csa->csa_keys          = get_key_struct();
+#endif
+}
+
+void
+tvhcsa_destroy ( tvhcsa_t *csa )
+{
+#if ENABLE_DVBCSA
+  dvbcsa_bs_key_free(csa->csa_key_odd);
+  dvbcsa_bs_key_free(csa->csa_key_even);
+  free(csa->csa_tsbbatch_odd);
+  free(csa->csa_tsbbatch_even);
+#else
+  free_key_struct(csa->csa_keys);
+#endif
+  free(csa->csa_tsbcluster);
+}
diff --git a/src/descrambler/tvhcsa.h b/src/descrambler/tvhcsa.h
new file mode 100644
index 00000000..48fdcee0
--- /dev/null
+++ b/src/descrambler/tvhcsa.h
@@ -0,0 +1,82 @@
+/*
+ *  tvheadend - CSA wrapper
+ *  Copyright (C) 2013 Adam Sutton
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __TVH_CSA_H__
+#define __TVH_CSA_H__
+
+struct mpegts_service;
+struct elementary_stream;
+
+#include <stdint.h>
+#if ENABLE_DVBCSA
+#include <dvbcsa/dvbcsa.h>
+#else
+#include "ffdecsa/FFdecsa.h"
+#endif
+
+typedef struct tvhcsa
+{
+
+  /**
+   * CSA
+   */
+  int      csa_cluster_size;
+  uint8_t *csa_tsbcluster;
+  int      csa_fill;
+
+#if ENABLE_DVBCSA
+  struct dvbcsa_bs_batch_s *csa_tsbbatch_even;
+  struct dvbcsa_bs_batch_s *csa_tsbbatch_odd;
+  int csa_fill_even;
+  int csa_fill_odd;
+
+  struct dvbcsa_bs_key_s *csa_key_even;
+  struct dvbcsa_bs_key_s *csa_key_odd;
+#else
+  void *csa_keys;
+#endif
+  
+} tvhcsa_t;
+
+#if ENABLE_DVBCSA
+
+#define tvhcsa_set_key_even(csa, cw)\
+  dvbcsa_bs_key_set(cw, (csa)->csa_key_even)
+
+#define tvhcsa_set_key_odd(csa, cw)\
+  dvbcsa_bs_key_set(cw, (csa)->csa_key_odd)
+
+#else
+
+#define tvhcsa_set_key_even(csa, cw)\
+  set_even_control_word((csa)->csa_keys, cw)
+
+#define tvhcsa_set_key_odd(csa, cw)\
+  set_odd_control_word((csa)->csa_keys, cw)
+
+#endif
+
+void
+tvhcsa_descramble
+  ( tvhcsa_t *csa, struct mpegts_service *s, struct elementary_stream *st,
+    const uint8_t *tsb, int cw_update_pending );
+
+void tvhcsa_init    ( tvhcsa_t *csa );
+void tvhcsa_destroy ( tvhcsa_t *csa );
+
+#endif /* __TVH_CSA_H__ */