diff --git a/lib/ykpiv.c b/lib/ykpiv.c
index c6a40a1..493cb32 100644
--- a/lib/ykpiv.c
+++ b/lib/ykpiv.c
@@ -130,7 +130,7 @@ ykpiv_rc ykpiv_disconnect(ykpiv_state *state) {
   return YKPIV_OK;
 }
 
-static ykpiv_rc _select_application(ykpiv_state *state) {
+static ykpiv_rc select_application(ykpiv_state *state) {
   APDU apdu;
   unsigned char data[0xff];
   unsigned long recv_len = sizeof(data);
@@ -184,14 +184,16 @@ ykpiv_rc ykpiv_connect(ykpiv_state *state, const char *wanted) {
     }
     rc = SCardConnect(state->context, reader_ptr, SCARD_SHARE_SHARED,
         SCARD_PROTOCOL_T1, &state->card, &active_protocol);
-    if(rc != SCARD_S_SUCCESS) {
+    if(rc != SCARD_S_SUCCESS)
+    {
       if(state->verbose) {
         fprintf(stderr, "SCardConnect failed, rc=%08lx\n", rc);
       }
       continue;
     }
-    if (_select_application(state) != YKPIV_OK)
+    if (select_application(state) != YKPIV_OK) {
       continue;
+    }
     return YKPIV_OK;
   }
 
@@ -207,7 +209,7 @@ ykpiv_rc ykpiv_connect(ykpiv_state *state, const char *wanted) {
   return YKPIV_GENERIC_ERROR;
 }
 
-static ykpiv_rc _reconnect(ykpiv_state *state) {
+static ykpiv_rc reconnect(ykpiv_state *state) {
   unsigned long active_protocol;
   long rc;
   ykpiv_rc res;
@@ -224,10 +226,12 @@ static ykpiv_rc _reconnect(ykpiv_state *state) {
     }
     return YKPIV_PCSC_ERROR;
   }
-  if ((res = _select_application(state)) != YKPIV_OK)
+  if ((res = select_application(state)) != YKPIV_OK) {
     return res;
-  if (state->pin)
+  }
+  if (state->pin) {
     return ykpiv_verify(state, state->pin, &tries);
+  }
   return YKPIV_OK;
 }
 
@@ -260,7 +264,8 @@ ykpiv_rc ykpiv_list_readers(ykpiv_state *state, char *readers, size_t *len) {
   }
 
   rc = SCardListReaders(state->context, NULL, readers, &num_readers);
-  if (rc != SCARD_S_SUCCESS) {
+  if (rc != SCARD_S_SUCCESS)
+  {
     if(state->verbose) {
       fprintf (stderr, "error: SCardListReaders failed, rc=%08lx\n", rc);
     }
@@ -274,16 +279,16 @@ ykpiv_rc ykpiv_list_readers(ykpiv_state *state, char *readers, size_t *len) {
   return YKPIV_OK;
 }
 
-static ykpiv_rc _begin_transaction(ykpiv_state *state) {
+static ykpiv_rc begin_transaction(ykpiv_state *state) {
   long rc;
   ykpiv_rc res;
 
   rc = SCardBeginTransaction(state->card);
   if((rc & 0xFFFFFFFF) == SCARD_W_RESET_CARD) {
-    if((res = _reconnect(state)) != YKPIV_OK) {
+    if((res = reconnect(state)) != YKPIV_OK) {
       return res;
     }
-    return _begin_transaction(state);
+    rc = SCardBeginTransaction(state->card);
   }
   if(rc != SCARD_S_SUCCESS) {
     if(state->verbose) {
@@ -294,7 +299,7 @@ static ykpiv_rc _begin_transaction(ykpiv_state *state) {
   return YKPIV_OK;
 }
 
-static ykpiv_rc _end_transaction(ykpiv_state *state) {
+static ykpiv_rc end_transaction(ykpiv_state *state) {
   long rc = SCardEndTransaction(state->card, SCARD_LEAVE_CARD);
   if(rc != SCARD_S_SUCCESS && state->verbose) {
     fprintf(stderr, "error: Failed to end pcsc transaction, rc=%08lx\n", rc);
@@ -304,87 +309,85 @@ static ykpiv_rc _end_transaction(ykpiv_state *state) {
 }
 
 ykpiv_rc ykpiv_transfer_data(ykpiv_state *state, const unsigned char *templ,
-   const unsigned char *in_data, long in_len,
-   unsigned char *out_data, unsigned long *out_len, int *sw) {
- const unsigned char *in_ptr = in_data;
- unsigned long max_out = *out_len;
- ykpiv_rc res;
- long rc;
- *out_len = 0;
+    const unsigned char *in_data, long in_len,
+    unsigned char *out_data, unsigned long *out_len, int *sw) {
+  const unsigned char *in_ptr = in_data;
+  unsigned long max_out = *out_len;
+  ykpiv_rc res;
+  long rc;
+  *out_len = 0;
 
- res = _begin_transaction(state);
- if (res != YKPIV_OK) {
-   return res;
- }
- do {
-   size_t this_size = 0xff;
-   unsigned char data[261];
-   unsigned long recv_len = sizeof(data);
-   APDU apdu;
+  res = begin_transaction(state);
+  if (res != YKPIV_OK) {
+    return res;
+  }
+  do {
+    size_t this_size = 0xff;
+    unsigned char data[261];
+    unsigned long recv_len = sizeof(data);
+    APDU apdu;
 
-   memset(apdu.raw, 0, sizeof(apdu.raw));
-   memcpy(apdu.raw, templ, 4);
-   if(in_ptr + 0xff < in_data + in_len) {
-     apdu.st.cla = 0x10;
-   } else {
-     this_size = (size_t)((in_data + in_len) - in_ptr);
-   }
-   if(state->verbose > 2) {
-     fprintf(stderr, "Going to send %lu bytes in this go.\n", (unsigned long)this_size);
-   }
-   apdu.st.lc = this_size;
-   memcpy(apdu.st.data, in_ptr, this_size);
-   res = send_data(state, &apdu, data, &recv_len, sw);
-   if(res != YKPIV_OK) {
-     _end_transaction(state);
-     return res;
-   } else if(*sw != SW_SUCCESS && *sw >> 8 != 0x61) {
-     _end_transaction(state);
-     return YKPIV_OK;
-   }
-   if(*out_len + recv_len - 2 > max_out) {
-     if(state->verbose) {
-       fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.\n", *out_len + recv_len - 2, max_out);
-     }
-     _end_transaction(state);
-     return YKPIV_SIZE_ERROR;
-   }
-   if(out_data) {
-     memcpy(out_data, data, recv_len - 2);
-     out_data += recv_len - 2;
-     *out_len += recv_len - 2;
-   }
-   in_ptr += this_size;
- } while(in_ptr < in_data + in_len);
- while(*sw >> 8 == 0x61) {
-   APDU apdu;
-   unsigned char data[261];
-   unsigned long recv_len = sizeof(data);
+    memset(apdu.raw, 0, sizeof(apdu.raw));
+    memcpy(apdu.raw, templ, 4);
+    if(in_ptr + 0xff < in_data + in_len) {
+      apdu.st.cla = 0x10;
+    } else {
+      this_size = (size_t)((in_data + in_len) - in_ptr);
+    }
+    if(state->verbose > 2) {
+      fprintf(stderr, "Going to send %lu bytes in this go.\n", (unsigned long)this_size);
+    }
+    apdu.st.lc = this_size;
+    memcpy(apdu.st.data, in_ptr, this_size);
+    res = send_data(state, &apdu, data, &recv_len, sw);
+    if(res != YKPIV_OK) {
+      end_transaction(state);
+      return res;
+    } else if(*sw != SW_SUCCESS && *sw >> 8 != 0x61) {
+      return end_transaction(state);
+    }
+    if(*out_len + recv_len - 2 > max_out) {
+      if(state->verbose) {
+        fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.\n", *out_len + recv_len - 2, max_out);
+      }
+      end_transaction(state);
+      return YKPIV_SIZE_ERROR;
+    }
+    if(out_data) {
+      memcpy(out_data, data, recv_len - 2);
+      out_data += recv_len - 2;
+      *out_len += recv_len - 2;
+    }
+    in_ptr += this_size;
+  } while(in_ptr < in_data + in_len);
+  while(*sw >> 8 == 0x61) {
+    APDU apdu;
+    unsigned char data[261];
+    unsigned long recv_len = sizeof(data);
 
-   if(state->verbose > 2) {
-     fprintf(stderr, "The card indicates there is %d bytes more data for us.\n", *sw & 0xff);
-   }
+    if(state->verbose > 2) {
+      fprintf(stderr, "The card indicates there is %d bytes more data for us.\n", *sw & 0xff);
+    }
 
-   memset(apdu.raw, 0, sizeof(apdu.raw));
-   apdu.st.ins = 0xc0;
-   res = send_data(state, &apdu, data, &recv_len, sw);
-   if(res != YKPIV_OK) {
-     _end_transaction(state);
-     return res;
-   } else if(*sw != SW_SUCCESS && *sw >> 8 != 0x61) {
-     _end_transaction(state);
-     return YKPIV_OK;
-   }
-   if(*out_len + recv_len - 2 > max_out) {
-     fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.", *out_len + recv_len - 2, max_out);
-   }
-   if(out_data) {
-     memcpy(out_data, data, recv_len - 2);
-     out_data += recv_len - 2;
-     *out_len += recv_len - 2;
-   }
- }
- return _end_transaction(state);
+    memset(apdu.raw, 0, sizeof(apdu.raw));
+    apdu.st.ins = 0xc0;
+    res = send_data(state, &apdu, data, &recv_len, sw);
+    if(res != YKPIV_OK) {
+      end_transaction(state);
+      return res;
+    } else if(*sw != SW_SUCCESS && *sw >> 8 != 0x61) {
+      return end_transaction(state);
+    }
+    if(*out_len + recv_len - 2 > max_out) {
+      fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.", *out_len + recv_len - 2, max_out);
+    }
+    if(out_data) {
+      memcpy(out_data, data, recv_len - 2);
+      out_data += recv_len - 2;
+      *out_len += recv_len - 2;
+    }
+  }
+  return end_transaction(state);
 }
 
 static ykpiv_rc send_data(ykpiv_state *state, APDU *apdu,
@@ -759,6 +762,9 @@ ykpiv_rc ykpiv_verify(ykpiv_state *state, const char *pin, int *tries) {
     if (pin) {
       free(state->pin);
       state->pin = malloc(len * sizeof(char) + 1);
+      if (state->pin == NULL) {
+        return YKPIV_MEMORY_ERROR;
+      }
       strcpy(state->pin, pin);
     }
     return YKPIV_OK;
@@ -828,6 +834,9 @@ ykpiv_rc ykpiv_change_pin(ykpiv_state *state, const char * current_pin, size_t c
   if (res == YKPIV_OK && new_pin != NULL) {
     free(state->pin);
     state->pin = malloc(new_pin_len * sizeof(char) + 1);
+    if (state->pin == NULL) {
+      return YKPIV_MEMORY_ERROR;
+    }
     strcpy(state->pin, new_pin);
   }
   return res;