diff --git a/include/osmocom/gsm/a5.h b/include/osmocom/gsm/a5.h
index fae3fdd..fa63246 100644
--- a/include/osmocom/gsm/a5.h
+++ b/include/osmocom/gsm/a5.h
@@ -1,5 +1,3 @@
-/*! \file gsm/a5.h
- *  Osmocom GSM A5 ciphering algorithm header. */
 /*
  * Copyright (C) 2011  Sylvain Munaut <tnt@246tNt.com>
  *
diff --git a/include/osmocom/gsm/gea.h b/include/osmocom/gsm/gea.h
index 5c23d2a..fff9baa 100644
--- a/include/osmocom/gsm/gea.h
+++ b/include/osmocom/gsm/gea.h
@@ -1,5 +1,8 @@
-/*! \file gea.h
- * GEA3 header.
+/*! \defgroup gea GPRS GEA3/GEA4 ciphering algorithm
+ *  @{
+ *  \file gea.h
+ *
+ * GEA3/GEA4 header.
  *
  * See gea.c for details
  */
@@ -15,3 +18,5 @@
 
 int gea4(uint8_t *out, uint16_t len, uint8_t *kc, uint32_t iv,
 	 enum gprs_cipher_direction direct);
+
+/*! @} */
diff --git a/src/gsm/a5.c b/src/gsm/a5.c
index e906b6d..ea09e17 100644
--- a/src/gsm/a5.c
+++ b/src/gsm/a5.c
@@ -1,10 +1,3 @@
-/*! \file a5.c
- * Full reimplementation of A5/1,2 (split and threadsafe).
- *
- * The logic behind the algorithm is taken from "A pedagogical implementation
- * of the GSM A5/1 and A5/2 "voice privacy" encryption algorithms." by
- * Marc Briceno, Ian Goldberg, and David Wagner.
- */
 /*
  * Copyright (C) 2011  Sylvain Munaut <tnt@246tNt.com>
  *
@@ -25,11 +18,16 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-/*! \addtogroup crypto
+/*! \addtogroup a5
  *  @{
- *  Osmocom GSM/GPRS ciphering algorithm implementation
+ *  Osmocom GSM ciphering algorithm implementation
  *
- * \file gsm/a5.c */
+ *  Full reimplementation of A5/1,2,3,4 (split and threadsafe).
+ *
+ *  The logic behind the algorithm is taken from "A pedagogical implementation
+ *  of the GSM A5/1 and A5/2 "voice privacy" encryption algorithms." by
+ *  Marc Briceno, Ian Goldberg, and David Wagner.
+ */
 
 #include <errno.h>
 #include <string.h>
diff --git a/src/gsm/gea.c b/src/gsm/gea.c
index d95c03e..70f08ad 100644
--- a/src/gsm/gea.c
+++ b/src/gsm/gea.c
@@ -1,5 +1,3 @@
-/*! \file gea.c
- * Implementation of GEA3 and GEA4. */
 /*
  * Copyright (C) 2016 by Sysmocom s.f.m.c. GmbH
  *
@@ -28,9 +26,10 @@
 #include <stdint.h>
 #include <string.h>
 
-/*! \addtogroup crypto
+/*! \addtogroup gea
  *  @{
- * \file gsm/gea.c */
+ *  Implementation of GPRS Ciphers GEA3 and GEA4.
+ * \file gea.c */
 
 /*! Performs the GEA4 algorithm as in 3GPP TS 55.226 V9.0.0
  *  \param[in,out] out Buffer for gamma for encrypted/decrypted