diff --git a/examples/echoserver/echoserver.c b/examples/echoserver/echoserver.c
index a9ef4af5..58819e0b 100644
--- a/examples/echoserver/echoserver.c
+++ b/examples/echoserver/echoserver.c
@@ -1898,11 +1898,14 @@ static int wsUserAuth(byte authType,
         wc_Sha256Hash(authData->sf.publicKey.publicKey,
                 authData->sf.publicKey.publicKeySz,
                 authHash);
-    #if defined(WOLFSSH_CERTS) && !defined(WOLFSSH_NO_FPKI)
-        /* Display FPKI info UUID and FASC-N */
+    #if defined(WOLFSSH_CERTS) && !defined(WOLFSSH_NO_FPKI) && \
+        defined(WOLFSSL_FPKI)
+        /* Display FPKI info UUID and FASC-N, getter function for FASC-N and
+         * UUID are dependent on wolfSSL version newer than 5.3.0 so gatting
+         * on the macro WOLFSSL_FPKI here too */
         if (authData->sf.publicKey.isCert) {
             DecodedCert cert;
-            byte* uuid;
+            byte* uuid = NULL;
             word32 fascnSz;
             word32 uuidSz;
             word32 i;
diff --git a/src/certman.c b/src/certman.c
index 89032d82..5ca24de9 100644
--- a/src/certman.c
+++ b/src/certman.c
@@ -86,33 +86,36 @@ struct WOLFSSH_CERTMAN {
 
 static WOLFSSH_CERTMAN* _CertMan_init(WOLFSSH_CERTMAN* cm, void* heap)
 {
+    WOLFSSH_CERTMAN* ret = NULL;
     WLOG_ENTER();
 
-    if (cm != NULL) {
-        WMEMSET(cm, 0, sizeof *cm);
-        cm->cm = wolfSSL_CertManagerNew_ex(heap);
-        if (cm->cm != NULL) {
-            int ret;
+    ret = cm;
+    if (ret != NULL) {
+        WMEMSET(ret, 0, sizeof(WOLFSSH_CERTMAN));
+        ret->cm = wolfSSL_CertManagerNew_ex(heap);
+        if (ret->cm == NULL) {
+            ret = NULL;
+        }
+    #ifdef HAVE_OCSP
+        else {
+            int err;
 
-            ret = wolfSSL_CertManagerEnableOCSP(cm->cm,
+            err = wolfSSL_CertManagerEnableOCSP(ret->cm,
                     WOLFSSL_OCSP_CHECKALL);
-
-            if (ret == WOLFSSL_SUCCESS) {
+            if (err == WOLFSSL_SUCCESS) {
                 WLOG(WS_LOG_CERTMAN, "Enabled OCSP");
             }
             else {
                 WLOG(WS_LOG_CERTMAN, "Couldn't enable OCSP");
-                wolfSSL_CertManagerFree(cm->cm);
-                cm = NULL;
+                wolfSSL_CertManagerFree(ret->cm);
+                ret = NULL;
             }
         }
-        else {
-            cm = NULL;
-        }
+    #endif
     }
 
-    WLOG_LEAVE_PTR(cm);
-    return cm;
+    WLOG_LEAVE_PTR(ret);
+    return ret;
 }
 
 
@@ -190,59 +193,148 @@ enum {
 };
 #endif /* WOLFSSH_NO_FPKI */
 
-int wolfSSH_CERTMAN_VerifyCert_buffer(WOLFSSH_CERTMAN* cm,
-        const unsigned char* cert, word32 certSz)
+/* if handling a chain it is expected to be the leaf cert first followed by
+ * intermediates and CA last (CA may be ommited) */
+int wolfSSH_CERTMAN_VerifyCerts_buffer(WOLFSSH_CERTMAN* cm,
+        const unsigned char* certs, word32 certSz, word32 certsCount)
 {
     int ret = WS_SUCCESS;
+    int idx;
+
+    unsigned char **certLoc; /* locations of certificate start */
+    word32        *certLen;  /* size of certificate, in sync with certLoc */
+
+    unsigned char *currentPt;
+    word32         currentSz;
 
     WLOG_ENTER();
 
-    if (ret == WS_SUCCESS) {
-        ret = wolfSSL_CertManagerVerifyBuffer(cm->cm, cert, certSz,
-                WOLFSSL_FILETYPE_ASN1);
+    certLoc = (unsigned char**)WMALLOC(certsCount * sizeof(unsigned char*),
+        cm->heap, DYNTYPE_CERT);
+    certLen = (word32*)WMALLOC(certsCount * sizeof(word32), cm->heap,
+        DYNTYPE_CERT);
 
-        if (ret == WOLFSSL_SUCCESS) {
-            ret = WS_SUCCESS;
-        }
-        else if (ret == ASN_NO_SIGNER_E) {
-            WLOG(WS_LOG_CERTMAN, "cert verify: no signer");
-            ret = WS_CERT_NO_SIGNER_E;
-        }
-        else if (ret == ASN_AFTER_DATE_E) {
-            WLOG(WS_LOG_CERTMAN, "cert verify: expired");
-            ret = WS_CERT_EXPIRED_E;
-        }
-        else if (ret == ASN_SIG_CONFIRM_E) {
-            WLOG(WS_LOG_CERTMAN, "cert verify: bad sig");
-            ret = WS_CERT_SIG_CONFIRM_E;
+    currentPt = (unsigned char*)certs; /* set initial certificate pointer */
+    currentSz = 0;
+
+    for (idx = 0; idx < (int)certsCount; idx++) {
+        word32 sz = 0;
+        certLoc[idx] = currentPt;
+
+        /* get the size of the certificate from first sequence */
+        if (currentSz + MAX_SEQ_SZ >= certSz) {
+            ret = WS_BUFFER_E;
+            break;
         }
         else {
-            WLOG(WS_LOG_CERTMAN, "cert verify: other error (%d)", ret);
-            ret = WS_CERT_OTHER_E;
+            /* at this point there is at least 5 bytes in currentPt */
+            if (currentPt[sz] != (ASN_SEQUENCE | ASN_CONSTRUCTED)) {
+                WLOG(WS_LOG_CERTMAN, "no cert sequence to get length from");
+                ret = ASN_PARSE_E;
+                break;
+            }
+            sz++;
+
+            if (ret == WS_SUCCESS) {
+                if (currentPt[sz] >= ASN_LONG_LENGTH) {
+                    word32 bytes = currentPt[sz++] & 0x7F;
+                    if (bytes > MAX_LENGTH_SZ) {
+                        WLOG(WS_LOG_CERTMAN, "length found is too large!");
+                        ret = ASN_PARSE_E;
+                        break;
+                    }
+                    else {
+                        byte b;
+                        certLen[idx] = 0;
+                        for (; bytes > 0; bytes--) {
+                            b = currentPt[sz++];
+                            certLen[idx] = (certLen[idx] << 8) | b;
+                        }
+                    }
+                }
+                else {
+                    certLen[idx] = (word32)currentPt[sz++];
+                }
+                sz += certLen[idx];
+                certLen[idx] = sz; /* update size to contain first sequence */
+            }
+        }
+
+        /* advance current pointer and update current total size */
+        if (ret == WS_SUCCESS) {
+            if (currentSz + sz > certSz) {
+                WLOG(WS_LOG_CERTMAN, "cert found is too large!");
+                ret = ASN_PARSE_E;
+                break;
+            }
+            currentSz += sz;
+            currentPt += sz;
         }
     }
 
     if (ret == WS_SUCCESS) {
-        ret = wolfSSL_CertManagerCheckOCSP(cm->cm, (byte*)cert, certSz);
+        for (idx = certsCount - 1; idx >= 0; idx--) {
+            WLOG(WS_LOG_CERTMAN, "verifying cert at index %d", idx);
+            ret = wolfSSL_CertManagerVerifyBuffer(cm->cm, certLoc[idx],
+                certLen[idx], WOLFSSL_FILETYPE_ASN1);
+            if (ret == WOLFSSL_SUCCESS) {
+                ret = WS_SUCCESS;
+            }
+            else if (ret == ASN_NO_SIGNER_E) {
+                WLOG(WS_LOG_CERTMAN, "cert verify: no signer");
+                ret = WS_CERT_NO_SIGNER_E;
+            }
+            else if (ret == ASN_AFTER_DATE_E) {
+                WLOG(WS_LOG_CERTMAN, "cert verify: expired");
+                ret = WS_CERT_EXPIRED_E;
+            }
+            else if (ret == ASN_SIG_CONFIRM_E) {
+                WLOG(WS_LOG_CERTMAN, "cert verify: bad sig");
+                ret = WS_CERT_SIG_CONFIRM_E;
+            }
+            else {
+                WLOG(WS_LOG_CERTMAN, "cert verify: other error (%d)", ret);
+                ret = WS_CERT_OTHER_E;
+            }
 
-        if (ret == WOLFSSL_SUCCESS) {
-            ret = WS_SUCCESS;
-        }
-        else if (ret == OCSP_CERT_REVOKED) {
-            WLOG(WS_LOG_CERTMAN, "ocsp lookup: ocsp revoked");
-            ret = WS_CERT_REVOKED_E;
-        }
-        else {
-            WLOG(WS_LOG_CERTMAN, "ocsp lookup: other error (%d)", ret);
-            ret = WS_CERT_OTHER_E;
+        #ifdef HAVE_OCSP
+            if (ret == WS_SUCCESS) {
+                ret = wolfSSL_CertManagerCheckOCSP(cm->cm, (byte*)certLoc[idx],
+                    certLen[idx]);
+
+                if (ret == WOLFSSL_SUCCESS) {
+                    ret = WS_SUCCESS;
+                }
+                else if (ret == OCSP_CERT_REVOKED) {
+                    WLOG(WS_LOG_CERTMAN, "ocsp lookup: ocsp revoked");
+                    ret = WS_CERT_REVOKED_E;
+                }
+                else {
+                    WLOG(WS_LOG_CERTMAN, "ocsp lookup: other error (%d)", ret);
+                    ret = WS_CERT_OTHER_E;
+                }
+            }
+        #endif /* HAVE_OCSP */
+
+            /* verified successfully, add intermideate as trusted */
+            if (ret == WS_SUCCESS && idx > 0) {
+                WLOG(WS_LOG_CERTMAN, "adding intermidiate cert as trusted");
+                ret = wolfSSH_CERTMAN_LoadRootCA_buffer(cm, certLoc[idx],
+                    certLen[idx]);
+            }
+
+            if (ret != WS_SUCCESS) {
+                break;
+            }
         }
     }
 
 #ifndef WOLFSSH_NO_FPKI
+    /* FPKI checking on the leaf certificate */
     if (ret == WS_SUCCESS) {
         DecodedCert decoded;
 
-        wc_InitDecodedCert(&decoded, cert, certSz, cm->cm);
+        wc_InitDecodedCert(&decoded, certLoc[0], certLen[0], cm->cm);
         ret = wc_ParseCert(&decoded, WOLFSSL_FILETYPE_ASN1, 0, cm->cm);
 
         if (ret == 0) {
@@ -387,16 +479,20 @@ static int CheckProfile(DecodedCert* cert, int profile)
         /* cycle through alt names to check for needed types */
         current = cert->altNames;
         while (current != NULL) {
+        #ifdef WOLFSSL_FPKI
             if (current->oidSum == FASCN_OID) {
                 hasFascN = 1;
             }
+        #endif /* WOLFSSL_FPKI */
 
             current = current->next;
         }
 
+    #ifdef WOLFSSL_FPKI
         if (wc_GetUUIDFromCert(cert, uuid, &uuidSz) == 0) {
             hasUUID = 1;
         }
+    #endif /* WOLFSSL_FPKI */
 
         /* all must have UUID and worksheet 6 must have FASC-N in addition to
          * UUID */
diff --git a/src/internal.c b/src/internal.c
index 9d6c1a2d..37027ea4 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -546,6 +546,8 @@ WOLFSSH_CTX* CtxInit(WOLFSSH_CTX* ctx, byte side, void* heap)
 #endif /* DEBUG_WOLFSSH */
 #ifdef WOLFSSH_CERTS
     ctx->certMan = wolfSSH_CERTMAN_new(ctx->heap);
+    if (ctx->certMan == NULL)
+        return NULL;
 #endif /* WOLFSSH_CERTS */
     ctx->windowSz = DEFAULT_WINDOW_SZ;
     ctx->maxPacketSz = DEFAULT_MAX_PACKET_SZ;
@@ -767,7 +769,6 @@ int wolfSSH_ProcessBuffer(WOLFSSH_CTX* ctx,
     word32 derSz, scratch = 0;
     union wolfSSH_key *key_ptr = NULL;
 
-    (void)wcType;
     (void)dynamicType;
     (void)heap;
 
@@ -846,7 +847,15 @@ int wolfSSH_ProcessBuffer(WOLFSSH_CTX* ctx,
         if (ctx->certMan != NULL) {
             ret = wolfSSH_CERTMAN_LoadRootCA_buffer(ctx->certMan, der, derSz);
         }
+        else {
+            WLOG(WS_LOG_DEBUG, "Error no cert manager set");
+            ret = WS_MEMORY_E;
+        }
         WFREE(der, heap, dynamicType);
+        if (ret < 0) {
+            WLOG(WS_LOG_DEBUG, "Error %d loading in CA buffer", ret);
+            goto end;
+        }
     }
     #endif /* WOLFSSH_CERTS */
     else {
@@ -911,6 +920,8 @@ int wolfSSH_ProcessBuffer(WOLFSSH_CTX* ctx,
 end:
     if (key_ptr)
         WFREE(key_ptr, heap, dynamicType);
+
+    (void)wcType;
     return ret;
 }
 
@@ -4546,11 +4557,6 @@ static int DoUserAuthRequestRsaCert(WOLFSSH* ssh, WS_UserAuthData_PublicKey* pk,
         }
     }
 
-    if (ret == WS_SUCCESS) {
-        ret = wolfSSH_CERTMAN_VerifyCert_buffer(ssh->ctx->certMan,
-                pk->publicKey, pk->publicKeySz);
-    }
-
     if (ret == WS_SUCCESS) {
         byte*  pub = NULL;
         word32 pubSz;
@@ -4895,13 +4901,6 @@ static int DoUserAuthRequestEccCert(WOLFSSH* ssh, WS_UserAuthData_PublicKey* pk,
         }
     }
 
-#ifdef WOLFSSH_CERTS
-    if (ret == WS_SUCCESS) {
-        ret = wolfSSH_CERTMAN_VerifyCert_buffer(ssh->ctx->certMan,
-                pk->publicKey, pk->publicKeySz);
-    }
-#endif /* WOLFSSH_CERTS */
-
     if (ret == WS_SUCCESS) {
         byte*  pub = NULL;
         word32 pubSz;
@@ -5037,6 +5036,9 @@ static int DoUserAuthRequestPublicKey(WOLFSSH* ssh, WS_UserAuthData* authData,
     int ret = WS_SUCCESS;
     int authFailure = 0;
     byte pkTypeId;
+#ifdef WOLFSSH_CERTS
+    word32 certCount = 0;
+#endif
 
     WLOG(WS_LOG_DEBUG, "Entering DoUserAuthRequestPublicKey()");
 
@@ -5063,14 +5065,15 @@ static int DoUserAuthRequestPublicKey(WOLFSSH* ssh, WS_UserAuthData* authData,
         pkTypeId = NameToId((char*)pk->publicKeyType, pk->publicKeyTypeSz);
         if (pkTypeId == ID_UNKNOWN) {
             WLOG(WS_LOG_DEBUG, "DUARPK: Unknown / Unsupported key type");
-            ret = WS_INVALID_ALGO_ID;
+            ret = SendUserAuthFailure(ssh, 0);
+            authFailure = 1;
         }
     }
 
-    if (ret == WS_SUCCESS)
+    if (ret == WS_SUCCESS && !authFailure)
         ret = GetSize(&pk->publicKeySz, buf, len, &begin);
 
-    if (ret == WS_SUCCESS) {
+    if (ret == WS_SUCCESS && !authFailure) {
         pk->publicKey = buf + begin;
         begin += pk->publicKeySz;
         #ifdef WOLFSSH_CERTS
@@ -5079,21 +5082,47 @@ static int DoUserAuthRequestPublicKey(WOLFSSH* ssh, WS_UserAuthData* authData,
             pkTypeId == ID_X509V3_ECDSA_SHA2_NISTP384 ||
             pkTypeId == ID_X509V3_ECDSA_SHA2_NISTP521) {
             word32 l = 0, m = 0;
+            word32 ocspCount = 0;
+            byte* ocspBuf = NULL;
+            word32 ocspBufSz = 0;
 
             /* Skip the name */
             ret = GetSize(&l, pk->publicKey, pk->publicKeySz, &m);
             m += l;
             /* Get the cert count */
-            ret = GetUint32(&l, pk->publicKey, pk->publicKeySz, &m);
             if (ret == WS_SUCCESS) {
-                ret = GetSize(&l, pk->publicKey, pk->publicKeySz, &m);
+                ret = GetUint32(&certCount, pk->publicKey, pk->publicKeySz, &m);
+                if (ret == WS_SUCCESS) {
+                    WLOG(WS_LOG_INFO, "Peer sent certificate count of %d",
+                        certCount);
+                    ret = GetSize(&l, pk->publicKey, pk->publicKeySz, &m);
+                }
             }
 
             if (ret == WS_SUCCESS) {
+                ocspBuf   = (byte*)pk->publicKey + m + l;
+                ocspBufSz = pk->publicKeySz - l;
+
                 pk->publicKeySz = l;
                 pk->publicKey = pk->publicKey + m;
                 pk->isCert = 1;
             }
+
+            /* get OCSP count */
+            if (ret == WS_SUCCESS) {
+                m = 0;
+                ret = GetUint32(&ocspCount, ocspBuf, ocspBufSz, &m);
+            }
+
+            if (ret == WS_SUCCESS) {
+                WLOG(WS_LOG_INFO, "Peer sent OCSP count of %d", ocspCount);
+            }
+
+            /* @TODO handle OCSP's */
+            if (ocspCount > 0) {
+                WLOG(WS_LOG_INFO, "Peer sent OCSP's, not yet handled");
+                ret = GetSize(&l, ocspBuf, ocspBufSz, &m);
+            }
         }
         #endif /* WOLFSSH_CERTS */
 
@@ -5177,26 +5206,13 @@ static int DoUserAuthRequestPublicKey(WOLFSSH* ssh, WS_UserAuthData* authData,
             }
 
             /* The rest of the fields in the signature are already
-             * in the buffer. Just need to account for the sizes. */
+             * in the buffer. Just need to account for the sizes, which total
+             * the length of the buffer minus the signature and uint32 size of
+             * signature. */
             if (ret == 0) {
                 word32 dataToSignSz;
 
-                dataToSignSz = authData->usernameSz +
-                               authData->serviceNameSz +
-                               authData->authNameSz + BOOLEAN_SZ +
-                               pk->publicKeyTypeSz + pk->publicKeySz +
-                               (UINT32_SZ * 5);
-
-                #ifdef WOLFSSH_CERTS
-                if (pkTypeId == ID_X509V3_SSH_RSA ||
-                    pkTypeId == ID_X509V3_ECDSA_SHA2_NISTP256 ||
-                    pkTypeId == ID_X509V3_ECDSA_SHA2_NISTP384 ||
-                    pkTypeId == ID_X509V3_ECDSA_SHA2_NISTP521) {
-
-                    dataToSignSz += pk->publicKeyTypeSz + (UINT32_SZ * 4);
-                }
-                #endif /* WOLFSSH_CERTS */
-
+                dataToSignSz = len - pk->signatureSz - UINT32_SZ;
                 ret = wc_HashUpdate(&hash, hashId,
                         pk->dataToSign, dataToSignSz);
             }
@@ -5210,6 +5226,15 @@ static int DoUserAuthRequestPublicKey(WOLFSSH* ssh, WS_UserAuthData* authData,
             }
             wc_HashFree(&hash, hashId);
 
+            #ifdef WOLFSSH_CERTS
+            /* verify certificates sent after the auth cb has allowed the
+             * connection */
+            if (ret == WS_SUCCESS && pk->isCert == 1 && certCount > 0) {
+                ret = wolfSSH_CERTMAN_VerifyCerts_buffer(ssh->ctx->certMan,
+                    pk->publicKey, pk->publicKeySz, certCount);
+            }
+            #endif
+
             if (ret == WS_SUCCESS) {
                 switch (pkTypeId) {
                     #ifndef WOLFSSH_NO_RSA
@@ -9917,6 +9942,7 @@ static int BuildUserAuthRequestEccCert(WOLFSSH* ssh,
     byte* r;
     byte* s;
     byte sig[139]; /* wc_ecc_sig_size() for a prime521 key. */
+    byte rs[139];  /* wc_ecc_sig_size() for a prime521 key. */
     word32 sigSz = sizeof(sig), rSz, sSz;
     byte* checkData = NULL;
     word32 checkDataSz = 0;
@@ -9985,9 +10011,9 @@ static int BuildUserAuthRequestEccCert(WOLFSSH* ssh,
         }
 
         if (ret == WS_SUCCESS) {
-            rSz = sSz = sizeof(sig) / 2;
-            r = sig;
-            s = sig + rSz;
+            rSz = sSz = sizeof(rs) / 2;
+            r = rs;
+            s = rs + rSz;
             ret = wc_ecc_sig_to_rs(sig, sigSz, r, &rSz, s, &sSz);
         }
 
@@ -10354,7 +10380,7 @@ int SendUserAuthRequest(WOLFSSH* ssh, byte authId, int addSig)
             ret = PrepareUserAuthRequestPublicKey(ssh, &payloadSz, &authData,
                     keySig_ptr);
         }
-        else if (authId != ID_NONE)
+        else if (authId != ID_NONE && !ssh->userAuthPkDone)
             ret = WS_INVALID_ALGO_ID;
     }
 
diff --git a/src/ssh.c b/src/ssh.c
index f299ebad..7b2a6c73 100644
--- a/src/ssh.c
+++ b/src/ssh.c
@@ -103,7 +103,10 @@ WOLFSSH_CTX* wolfSSH_CTX_new(byte side, void* heap)
     }
 
     ctx = (WOLFSSH_CTX*)WMALLOC(sizeof(WOLFSSH_CTX), heap, DYNTYPE_CTX);
-    ctx = CtxInit(ctx, side, heap);
+    if (CtxInit(ctx, side, heap) == NULL) {
+        WFREE(ctx, heap, DYNTYPE_CTX);
+        ctx = NULL;
+    }
 
     WLOG(WS_LOG_DEBUG, "Leaving wolfSSH_CTX_new(), ctx = %p", ctx);
 
diff --git a/wolfssh/certman.h b/wolfssh/certman.h
index 3d2218d7..09859aad 100644
--- a/wolfssh/certman.h
+++ b/wolfssh/certman.h
@@ -51,8 +51,8 @@ int wolfSSH_CERTMAN_LoadRootCA_buffer(WOLFSSH_CERTMAN* cm,
         const unsigned char* rootCa, word32 rootCaSz);
 
 WOLFSSH_API
-int wolfSSH_CERTMAN_VerifyCert_buffer(WOLFSSH_CERTMAN* cm,
-        const unsigned char* cert, word32 certSz);
+int wolfSSH_CERTMAN_VerifyCerts_buffer(WOLFSSH_CERTMAN* cm,
+        const unsigned char* cert, word32 certSz, word32 certCount);
 
 
 #ifdef __cplusplus