diff --git a/jni/c/src/fr_acinq_secp256k1_Secp256k1CFunctions.c b/jni/c/src/fr_acinq_secp256k1_Secp256k1CFunctions.c
index 44e7257..b25a8f7 100644
--- a/jni/c/src/fr_acinq_secp256k1_Secp256k1CFunctions.c
+++ b/jni/c/src/fr_acinq_secp256k1_Secp256k1CFunctions.c
@@ -1372,12 +1372,16 @@ JNIEXPORT jobjectArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp2
   if (jctx == 0)
       return NULL;
 
-  if (jseed32 != NULL)
+  if (jseed32 == NULL)
     return NULL;
 
-  if (jids33 != NULL)
+  if (jids33 == NULL)
     return NULL;
 
+  CHECKRESULT(jthreshold <= 0, "threshold can't be 0");
+  CHECKRESULT(jn_participants <= 0, "n_participants can't be 0");
+  CHECKRESULT(jthreshold > jn_participants, "threshold can't be greater then n_participants");
+
   size = (*penv)->GetArrayLength(penv, jseed32);
   CHECKRESULT(size != 32, "invalid seed32 size");
   copy_bytes_from_java(penv, jseed32, size, seed32);
@@ -1461,6 +1465,19 @@ JNIEXPORT jobjectArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp2
   if (jctx == 0)
     return NULL;
 
+  if (jshares == NULL)
+    return NULL;
+
+  if (jvss_commitments == NULL)
+    return NULL;
+  
+  if (jid33 == NULL)
+    return NULL;
+
+  CHECKRESULT(jthreshold <= 0, "threshold can't be 0");
+  CHECKRESULT(jtotalShareCount <= 0, "totalShareCount can't be 0");
+  CHECKRESULT(jthreshold > jtotalShareCount, "threshold can't be greater then totalShareCount");
+
   count = (*penv)->GetArrayLength(penv, jnonces);
   CHECKRESULT(count != jtotalShareCount, "jshares count should be total share count.");
   shares = calloc(count, sizeof(secp256k1_frost_share*));
@@ -1551,6 +1568,17 @@ JNIEXPORT jint JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256k1_1fr
   if (jctx == 0)
     return NULL;
 
+  if (jid33 == NULL)
+    return NULL;
+
+  if (jshare == NULL)
+    return NULL;
+
+  if (jvss_commitment == NULL)
+    return NULL;
+
+  CHECKRESULT(jthreshold <= 0, "threshold can't be 0");
+
   share = calloc(1, sizeof(secp256k1_frost_share));
   size = (*penv)->GetArrayLength(penv, jshare);
 //      TODO:  CHECKRESULT1(size != fr_acinq_secp256k1_Secp256k1CFunctions_SECP256K1_MUSIG_PUBLIC_NONCE_SIZE, "invalid public nonce size", free_nonces(pubnonces, count));
@@ -1604,6 +1632,16 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
   if (jctx == 0)
     return NULL;
 
+  if (jid33 == NULL)
+    return NULL;
+
+  if (jvss_commitments == NULL)
+    return NULL;
+
+  CHECKRESULT(jthreshold <= 0, "threshold can't be 0");
+  CHECKRESULT(jtotalSignersCount <= 0, "totalSignersCount can't be 0");
+  CHECKRESULT(jthreshold > jtotalSignersCount, "totalSignersCount can't be greater then n_participants");
+
   id33 = (*penv)->GetByteArrayElements(penv, jid33, 0);
 
   count = (*penv)->GetArrayLength(penv, jvss_commitments);
@@ -1658,6 +1696,9 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
   if (jctx == 0)
     return NULL;
 
+  if (jpublicKey == NULL)
+    return NULL;
+
   pub = (*penv)->GetByteArrayElements(penv, jpublicKey, 0);
   result = secp256k1_xonly_pubkey_parse(ctx, &public_key, (unsigned char *)pub);
   (*penv)->ReleaseByteArrayElements(penv, jpublicKey, pub, 0);
@@ -1756,6 +1797,8 @@ JNIEXPORT jobjectArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp2
     return NULL;
   if (jtweak_cache == NULL)
     return NULL;
+  if (jtweak32 == NULL)
+    return NULL;
 
   size = (*penv)->GetArrayLength(penv, jtweak_cache);
   CHECKRESULT(size != sizeof(secp256k1_frost_tweak_cache), "invalid tweak_cache size");
@@ -1818,8 +1861,9 @@ JNIEXPORT jobjectArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp2
   if (jctx == 0)
     return NULL;
 
-  if (jsession_id32 == 0)
+  if (jsession_id32 == NULL)
     return NULL;
+
   size = (*penv)->GetArrayLength(penv, jsession_id32);
   CHECKRESULT(size != 32, "invalid session_id size");
   copy_bytes_from_java(penv, jsession_id32, size, session_id32);
@@ -1914,8 +1958,26 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
   if (jctx == 0)
     return NULL;
 
+  if (jpubnonces == NULL)
+    return NULL;
+
+  if (jmsg32 == NULL)
+    return NULL;
+
+  if (jpubkey == NULL)
+    return NULL;
+
+  if (jmy_id33 == NULL)
+    return NULL;
+
+  if (jids33 == NULL)
+    return NULL;
+
+  CHECKRESULT(n_pubnonces <= 0, "n_pubnonces can't be 0");
+
   count = (*penv)->GetArrayLength(penv, jpubnonces);
   CHECKRESULT(count <= 0, "public nonces count cannot be 0");
+  CHECKRESULT(n_pubnonces != 0, "n_pubnonces doesn't match public nonces count");
 
   pubnonces = calloc(count, sizeof(secp256k1_frost_pubnonce *));
 
@@ -1931,12 +1993,9 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
     CHECKRESULT1(!result, "secp256k1_frost_pubnonce_parse failed", free_nonces(pubnonces, count));
   }
 
-  if (jmsg32 != NULL)
-  {
-    size = (*penv)->GetArrayLength(penv, jmsg32);
-    CHECKRESULT(size != 32, "invalid message size");
-    copy_bytes_from_java(penv, jmsg32, size, msg32);
-  }
+  size = (*penv)->GetArrayLength(penv, jmsg32);
+  CHECKRESULT(size != 32, "invalid message size");
+  copy_bytes_from_java(penv, jmsg32, size, msg32);
 
   pub = (*penv)->GetByteArrayElements(penv, jpubkey, 0);
   result = secp256k1_xonly_pubkey_parse(ctx, &public_key, (unsigned char *)pub);
@@ -1945,23 +2004,23 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
 
   id33 = (*penv)->GetByteArrayElements(penv, jmy_id33, 0);
 
-  // Copy over data from jids33
-  if (jids33 != NULL)
+  size = (*penv)->GetArrayLength(penv, jids33);
+  CHECKRESULT(size != n_pubnonces, "invalid ids33 size");
+  for (i = 0; i < n_pubnonces; i++)
   {
-    size = (*penv)->GetArrayLength(penv, jids33);
-    CHECKRESULT(size != n_pubnonces, "invalid ids33 size");
-    for (i = 0; i < n_pubnonces; i++)
-    {
-      jbyteArray id33 = (jbyteArray)(*penv)->GetObjectArrayElement(penv, jids33, i);
-      // TODO: Check id33 size is 33...
-      ids33[i] = (*penv)->GetByteArrayElements(penv, id33, 0);
-    }
+    jbyteArray id33 = (jbyteArray)(*penv)->GetObjectArrayElement(penv, jids33, i);
+    // TODO: Check id33 size is 33...
+    ids33[i] = (*penv)->GetByteArrayElements(penv, id33, 0);
   }
 
 
-  size = (*penv)->GetArrayLength(penv, jtweak_cache);
-  CHECKRESULT(size != sizeof(secp256k1_frost_tweak_cache), "invalid tweak_cache size");
-  copy_bytes_from_java(penv, jtweak_cache, size, tweak_cache.data);
+  if (jtweak_cache != NULL) 
+  {
+    size = (*penv)->GetArrayLength(penv, jtweak_cache);
+    CHECKRESULT(size != sizeof(secp256k1_frost_tweak_cache), "invalid tweak_cache size");
+    copy_bytes_from_java(penv, jtweak_cache, size, tweak_cache.data);
+  }
+  
 
   if (jadaptor != NULL)
   {
@@ -1970,6 +2029,7 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
     (*penv)->ReleaseByteArrayElements(penv, jadaptor, pub, 0);
     CHECKRESULT(!result, "secp256k1_ec_pubkey_parse failed");
   }
+
   int result  = secp256k1_frost_nonce_process(
     ctx,
     &session,
@@ -1979,10 +2039,9 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
     &public_key,
     id33,
     ids33,
-    &tweak_cache,
-    jadaptor == NULL ? NULL : adaptor
+    jtweak_cache == NULL ? NULL : &tweak_cache,
+    jadaptor == NULL ? NULL : &adaptor
   );
-
   CHECKRESULT(!result, "secp256k1_frost_nonce_process failed");
 
   size = sizeof(secp256k1_frost_session);
@@ -2020,24 +2079,35 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
   if (jctx == 0)
     return NULL;
 
+  if (jsecnonce == NULL)
+    return NULL;
+
+  if (jagg_share == NULL)
+    return NULL;
+
+  if (jsession == NULL)
+    return NULL;
+
   copy_bytes_from_java(penv, jsecnonce, fr_acinq_secp256k1_Secp256k1CFunctions_SECP256K1_MUSIG_SECRET_NONCE_SIZE, secnonce.data);
 
-  if (jagg_share != NULL) {
-    agg_share = calloc(1, sizeof(secp256k1_frost_share));
-    size = (*penv)->GetArrayLength(penv, jagg_share);
-    CHECKRESULT1(size != sizeof(secp256k1_frost_share), "invalid agg_share size", free_shares(shares, count));
-    in32 = (*penv)->GetByteArrayElements(penv, jagg_share, 0);
-    result = secp256k1_frost_share_parse(ctx, agg_share, (unsigned char *)in32);
-    (*penv)->ReleaseByteArrayElements(penv, jagg_share, in32, 0);
-    CHECKRESULT1(!result, "secp256k1_frost_share_parse failed", free_shares(shares, count));
-  }
+  agg_share = calloc(1, sizeof(secp256k1_frost_share));
+  size = (*penv)->GetArrayLength(penv, jagg_share);
+  CHECKRESULT1(size != sizeof(secp256k1_frost_share), "invalid agg_share size", free_shares(shares, count));
+  in32 = (*penv)->GetByteArrayElements(penv, jagg_share, 0);
+  result = secp256k1_frost_share_parse(ctx, agg_share, (unsigned char *)in32);
+  (*penv)->ReleaseByteArrayElements(penv, jagg_share, in32, 0);
+  CHECKRESULT1(!result, "secp256k1_frost_share_parse failed", free_shares(shares, count));
 
   CHECKRESULT((*penv)->GetArrayLength(penv, jsession) != fr_acinq_secp256k1_Secp256k1CFunctions_SECP256K1_MUSIG_SESSION_SIZE, "invalid session size");
   copy_bytes_from_java(penv, jsession, fr_acinq_secp256k1_Secp256k1CFunctions_SECP256K1_MUSIG_SESSION_SIZE, session.data);
 
-  size = (*penv)->GetArrayLength(penv, jtweak_cache);
-  CHECKRESULT(size != sizeof(secp256k1_frost_tweak_cache), "invalid tweak_cache size");
-  copy_bytes_from_java(penv, jtweak_cache, size, tweak_cache.data);
+  if (jtweak_cache != NULL) 
+  {
+    size = (*penv)->GetArrayLength(penv, jtweak_cache);
+    CHECKRESULT(size != sizeof(secp256k1_frost_tweak_cache), "invalid tweak_cache size");
+    copy_bytes_from_java(penv, jtweak_cache, size, tweak_cache.data);
+  }
+  
 
   int result  = secp256k1_frost_partial_sign(
     ctx,
@@ -2045,7 +2115,7 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
     &secnonce,
     &agg_share,
     &session,
-    &tweak_cache
+    jtweak_cache == NULL ? NULL : &tweak_cache
   );
   CHECKRESULT(!result, "secp256k1_frost_partial_sign failed");
 
@@ -2083,6 +2153,18 @@ JNIEXPORT jint JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256k1_1fr
   if (jctx == 0)
     return NULL;
 
+  if (jpartial_sig == NULL)
+    return NULL;
+  
+  if (jpubnonce == NULL)
+    return NULL;
+
+  if (jpubshare == NULL)
+    return NULL;
+
+  if (jsession == NULL)
+    return NULL;
+
   ptr = (*penv)->GetByteArrayElements(penv, jpartial_sig, 0);
   result = secp256k1_frost_partial_sig_parse(ctx, &partial_sig, ptr);
   (*penv)->ReleaseByteArrayElements(penv, jpartial_sig, ptr, 0);
@@ -2106,9 +2188,13 @@ JNIEXPORT jint JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256k1_1fr
   CHECKRESULT(size != sizeof(secp256k1_frost_session), "invalid session size");
   copy_bytes_from_java(penv, jsession, size, session.data);
 
-  size = (*penv)->GetArrayLength(penv, jtweak_cache);
-  CHECKRESULT(size != sizeof(secp256k1_frost_tweak_cache), "invalid tweak_cache size");
-  copy_bytes_from_java(penv, jtweak_cache, size, tweak_cache.data);
+  if (jtweak_cache != NULL) 
+  {
+    size = (*penv)->GetArrayLength(penv, jtweak_cache);
+    CHECKRESULT(size != sizeof(secp256k1_frost_tweak_cache), "invalid tweak_cache size");
+    copy_bytes_from_java(penv, jtweak_cache, size, tweak_cache.data);
+  }
+  
 
   int result = secp256k1_frost_partial_sig_verify(
     ctx,
@@ -2156,9 +2242,15 @@ JNIEXPORT jbyteArray JNICALL Java_fr_acinq_secp256k1_Secp256k1CFunctions_secp256
 
   if (jctx == 0)
     return NULL;
+
   if (jsession == NULL)
     return NULL;
 
+  if (jpartial_sigs == NULL)
+    return NULL;
+
+  CHECKRESULT(jn_sigs <= 0, "n_sigs can't be 0");
+
   size = (*penv)->GetArrayLength(penv, jsession);
   CHECKRESULT(size != sizeof(secp256k1_frost_session), "invalid session size");
   copy_bytes_from_java(penv, jsession, size, session.data);