diff --git a/src/encauth/ccm/ccm_add_aad.c b/src/encauth/ccm/ccm_add_aad.c
index 9b0cf0c..3dcf3ff 100644
--- a/src/encauth/ccm/ccm_add_aad.c
+++ b/src/encauth/ccm/ccm_add_aad.c
@@ -25,6 +25,9 @@ int ccm_add_aad(ccm_state *ccm,
    unsigned long y;
    int            err;
 
+   LTC_ARGCHK(ccm   != NULL);
+   LTC_ARGCHK(adata != NULL);
+
    if (ccm->aadlen < ccm->current_aadlen + adatalen) {
       return CRYPT_INVALID_ARG;
    }
diff --git a/src/encauth/ccm/ccm_add_nonce.c b/src/encauth/ccm/ccm_add_nonce.c
index 1cae548..fc4eafc 100644
--- a/src/encauth/ccm/ccm_add_nonce.c
+++ b/src/encauth/ccm/ccm_add_nonce.c
@@ -25,6 +25,9 @@ int ccm_add_nonce(ccm_state *ccm,
    unsigned long x, y, len;
    int           err;
 
+   LTC_ARGCHK(ccm   != NULL);
+   LTC_ARGCHK(nonce != NULL);
+
    /* increase L to match the nonce len */
    ccm->noncelen = (noncelen > 13) ? 13 : noncelen;
    if ((15 - ccm->noncelen) > ccm->L) {
diff --git a/src/encauth/ccm/ccm_done.c b/src/encauth/ccm/ccm_done.c
index 5ca6a78..64c9f9f 100644
--- a/src/encauth/ccm/ccm_done.c
+++ b/src/encauth/ccm/ccm_done.c
@@ -25,6 +25,8 @@ int ccm_done(ccm_state *ccm,
    unsigned long x, y;
    int            err;
 
+   LTC_ARGCHK(ccm != NULL);
+
    /* Check all data have been processed */
    if (ccm->ptlen != ccm->current_ptlen) {
       return CRYPT_ERROR;
diff --git a/src/encauth/ccm/ccm_init.c b/src/encauth/ccm/ccm_init.c
index 4819bda..8a6dfbc 100644
--- a/src/encauth/ccm/ccm_init.c
+++ b/src/encauth/ccm/ccm_init.c
@@ -29,6 +29,7 @@ int ccm_init(ccm_state *ccm, int cipher,
 {
    int            err;
 
+   LTC_ARGCHK(ccm    != NULL);
    LTC_ARGCHK(key    != NULL);
    LTC_ARGCHK(taglen != 0);
 
diff --git a/src/encauth/ccm/ccm_process.c b/src/encauth/ccm/ccm_process.c
index f784473..1f650ca 100644
--- a/src/encauth/ccm/ccm_process.c
+++ b/src/encauth/ccm/ccm_process.c
@@ -29,6 +29,8 @@ int ccm_process(ccm_state *ccm,
    unsigned char  y, z, b;
    int err;
 
+   LTC_ARGCHK(ccm != NULL);
+
    /* Check aad has been correctly added */
    if (ccm->aadlen != ccm->current_aadlen) {
       return CRYPT_ERROR;