diff --git a/src/SignatureTST.cpp b/src/SignatureTST.cpp
index 3061efdbe..75299a426 100644
--- a/src/SignatureTST.cpp
+++ b/src/SignatureTST.cpp
@@ -21,6 +21,7 @@
 
 #include "ASiC_S.h"
 #include "DataFile_p.h"
+#include "crypto/Digest.h"
 #include "crypto/TS.h"
 #include "crypto/X509Cert.h"
 #include "util/DateTime.h"
diff --git a/src/SignatureXAdES_T.cpp b/src/SignatureXAdES_T.cpp
index 1b4a833ae..5689a1073 100644
--- a/src/SignatureXAdES_T.cpp
+++ b/src/SignatureXAdES_T.cpp
@@ -25,6 +25,7 @@
 #include "crypto/Signer.h"
 #include "crypto/TS.h"
 #include "crypto/X509Cert.h"
+#include "crypto/X509CertStore.h"
 #include "util/DateTime.h"
 #include "util/log.h"
 
@@ -113,9 +114,7 @@ void SignatureXAdES_T::validate(const std::string &policy) const
             signatures->c14n(digest, canonicalizationMethod, signatureValue());
         });
 
-        tm tm = tsa.time();
-        time_t validateTime = util::date::mkgmtime(tm);
-        if(!signingCertificate().isValid(&validateTime))
+        if(!X509CertStore::instance()->verify(signingCertificate(), policy == POLv1, tsa.time()))
             THROW("Signing certificate was not valid on signing time");
 
         auto completeCertRefs = usp/"CompleteCertificateRefs";
diff --git a/src/XMLDocument.h b/src/XMLDocument.h
index 5ea27733f..134714322 100644
--- a/src/XMLDocument.h
+++ b/src/XMLDocument.h
@@ -21,6 +21,7 @@
 
 #include "crypto/Digest.h"
 #include "util/log.h"
+#include "util/memory.h"
 
 #include <libxml/parser.h>
 #include <libxml/xmlschemas.h>
@@ -39,23 +40,6 @@ namespace digidoc {
 
 #define VERSION_CHECK(major, minor, patch) (((major)<<16)|((minor)<<8)|(patch))
 
-template<typename> struct unique_xml;
-template<class T>
-struct unique_xml<void(T *)>
-{
-    using type = std::unique_ptr<T,void(*)(T *)>;
-};
-
-template<typename T>
-using unique_xml_t = typename unique_xml<T>::type;
-
-template<class T, typename D>
-[[nodiscard]]
-constexpr std::unique_ptr<T, D> make_unique_ptr(T *p, D d) noexcept
-{
-    return {p, std::forward<D>(d)};
-}
-
 static std::vector<unsigned char> from_base64(std::string_view data)
 {
     static constexpr std::string_view whitespace {" \n\r\f\t\v"};
@@ -300,7 +284,7 @@ struct XMLNode: public XMLElem<xmlNode>
     }
 };
 
-struct XMLDocument: public unique_xml_t<decltype(xmlFreeDoc)>, public XMLNode
+struct XMLDocument: public unique_free_t<xmlDoc>, public XMLNode
 {
     static constexpr std::string_view C14D_ID_1_0 {"http://www.w3.org/TR/2001/REC-xml-c14n-20010315"};
     static constexpr std::string_view C14D_ID_1_0_COM {"http://www.w3.org/TR/2001/REC-xml-c14n-20010315#WithComments"};
@@ -312,7 +296,7 @@ struct XMLDocument: public unique_xml_t<decltype(xmlFreeDoc)>, public XMLNode
     using XMLNode::operator bool;
 
     XMLDocument(element_type *ptr = {}, const XMLName &n = {}) noexcept
-        : std::unique_ptr<element_type, deleter_type>(ptr, xmlFreeDoc)
+        : unique_free_t<xmlDoc>(ptr, xmlFreeDoc)
         , XMLNode{xmlDocGetRootElement(get())}
     {
         if(d && !n.name.empty() && n.name != name() && !n.ns.empty() && n.ns != ns())
diff --git a/src/crypto/Connect.cpp b/src/crypto/Connect.cpp
index d03d16362..077cde27a 100644
--- a/src/crypto/Connect.cpp
+++ b/src/crypto/Connect.cpp
@@ -30,6 +30,7 @@
 #include <zlib.h>
 
 #include <algorithm>
+#include <sstream>
 #include <thread>
 
 #ifdef _WIN32
@@ -147,13 +148,13 @@ Connect::Connect(const string &_url, string _method, int _timeout, const vector<
         if(!certs.empty())
         {
             SSL_CTX_set_verify(ssl.get(), SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, nullptr);
-            SSL_CTX_set_cert_verify_callback(ssl.get(), [](X509_STORE_CTX *store, void *data) -> int {
-                X509 *x509 = X509_STORE_CTX_get0_cert(store);
-                auto *certs = (vector<X509Cert>*)data;
-                return any_of(certs->cbegin(), certs->cend(), [x509](const X509Cert &cert) {
-                    return cert && cert == x509;
-                }) ? 1 : 0;
-            }, const_cast<vector<X509Cert>*>(&certs));
+            X509_STORE *store = SSL_CTX_get_cert_store(ssl.get());
+            X509_STORE_set_flags(store, X509_V_FLAG_TRUSTED_FIRST | X509_V_FLAG_PARTIAL_CHAIN);
+            for(const X509Cert &cert: certs)
+            {
+                if(cert.handle())
+                    X509_STORE_add_cert(store, cert.handle());
+            }
         }
         BIO *sbio = BIO_new_ssl(ssl.get(), 1);
         if(!sbio)
@@ -292,7 +293,7 @@ Connect::Result Connect::exec(initializer_list<pair<string_view,string_view>> he
     stringstream stream(r.content);
     string line;
     auto to_lower = [](string str) {
-        std::transform(str.begin(), str.end(), str.begin(), ::tolower);
+        transform(str.begin(), str.end(), str.begin(), ::tolower);
         return str;
     };
     while(getline(stream, line))
diff --git a/src/crypto/Digest.cpp b/src/crypto/Digest.cpp
index 263d86cc5..cb7277618 100644
--- a/src/crypto/Digest.cpp
+++ b/src/crypto/Digest.cpp
@@ -26,6 +26,7 @@
 #include <openssl/x509.h>
 
 #include <array>
+#include <istream>
 
 using namespace std;
 using namespace digidoc;
@@ -37,7 +38,7 @@ using namespace digidoc;
  * @throws Exception throws exception if the digest calculator initialization failed.
  */
 Digest::Digest(string_view uri)
-    : d(SCOPE_PTR(EVP_MD_CTX, EVP_MD_CTX_new()))
+    : d(EVP_MD_CTX_new(), EVP_MD_CTX_free)
 {
     if(uri.empty() && Conf::instance()->digestUri() == URI_SHA1)
         THROW("Unsupported digest method %.*s", int(uri.size()), uri.data());
@@ -269,7 +270,7 @@ vector<unsigned char> Digest::result() const
     return result;
 }
 
-vector<unsigned char> Digest::result(const vector<unsigned char> &data)
+vector<unsigned char> Digest::result(const vector<unsigned char> &data) const
 {
     update(data.data(), data.size());
     return result();
diff --git a/src/crypto/Digest.h b/src/crypto/Digest.h
index d9472fc82..c00e3f669 100644
--- a/src/crypto/Digest.h
+++ b/src/crypto/Digest.h
@@ -21,7 +21,8 @@
 
 #include "../Exports.h"
 
-#include <memory>
+#include "util/memory.h"
+
 #include <string>
 #include <vector>
 
@@ -73,7 +74,7 @@ namespace digidoc
           Digest(std::string_view uri = {});
           void update(const unsigned char *data, size_t length) const;
           void update(std::istream &is) const;
-          std::vector<unsigned char> result(const std::vector<unsigned char> &data);
+          std::vector<unsigned char> result(const std::vector<unsigned char> &data) const;
           std::vector<unsigned char> result() const;
           std::string uri() const;
 
@@ -89,7 +90,7 @@ namespace digidoc
           static std::string digestInfoUri(const std::vector<unsigned char> &digest);
 
       private:
-          std::unique_ptr<EVP_MD_CTX, void (*)(EVP_MD_CTX*)> d;
+          unique_free_t<EVP_MD_CTX> d;
     };
 
 }
diff --git a/src/crypto/OCSP.cpp b/src/crypto/OCSP.cpp
index e05125d58..c6b9b3e21 100644
--- a/src/crypto/OCSP.cpp
+++ b/src/crypto/OCSP.cpp
@@ -46,6 +46,8 @@ using namespace std;
  * Initialize OCSP certificate validator.
  */
 OCSP::OCSP(const X509Cert &cert, const X509Cert &issuer, const std::string &userAgent)
+    : resp(nullptr, OCSP_RESPONSE_free)
+    , basic(nullptr, OCSP_BASICRESP_free)
 {
     if(!cert)
         THROW("Can not check X.509 certificate, certificate is NULL pointer.");
@@ -56,7 +58,7 @@ OCSP::OCSP(const X509Cert &cert, const X509Cert &issuer, const std::string &user
     if(url.empty())
     {
         STACK_OF(OPENSSL_STRING) *urls = X509_get1_ocsp(cert.handle());
-        if(sk_OPENSSL_STRING_num(urls) > 0)
+        if(urls && sk_OPENSSL_STRING_num(urls) > 0)
             url = sk_OPENSSL_STRING_value(urls, 0);
         X509_email_free(urls);
     }
@@ -90,8 +92,8 @@ OCSP::OCSP(const X509Cert &cert, const X509Cert &issuer, const std::string &user
         THROW("OCSP service responded - Forbidden");
     if(!result)
         THROW("Failed to send OCSP request");
-    const unsigned char *p2 = (const unsigned char*)result.content.c_str();
-    resp.reset(d2i_OCSP_RESPONSE(nullptr, &p2, long(result.content.size())), OCSP_RESPONSE_free);
+    const auto *p2 = (const unsigned char*)result.content.c_str();
+    resp.reset(d2i_OCSP_RESPONSE(nullptr, &p2, long(result.content.size())));
 
     switch(int respStatus = OCSP_response_status(resp.get()))
     {
@@ -106,7 +108,7 @@ OCSP::OCSP(const X509Cert &cert, const X509Cert &issuer, const std::string &user
         THROW("OCSP request failed, response status: %s", OCSP_response_status_str(respStatus));
     }
 
-    basic.reset(OCSP_response_get1_basic(resp.get()), OCSP_BASICRESP_free);
+    basic.reset(OCSP_response_get1_basic(resp.get()));
     if(!basic)
         THROW("Incorrect OCSP response.");
 
@@ -127,12 +129,14 @@ OCSP::OCSP(const X509Cert &cert, const X509Cert &issuer, const std::string &user
 }
 
 OCSP::OCSP(const unsigned char *data, size_t size)
+    : resp(nullptr, OCSP_RESPONSE_free)
+    , basic(nullptr, OCSP_BASICRESP_free)
 {
     if(size == 0)
         return;
-    resp.reset(d2i_OCSP_RESPONSE(nullptr, &data, long(size)), OCSP_RESPONSE_free);
+    resp.reset(d2i_OCSP_RESPONSE(nullptr, &data, long(size)));
     if(resp)
-        basic.reset(OCSP_response_get1_basic(resp.get()), OCSP_BASICRESP_free);
+        basic.reset(OCSP_response_get1_basic(resp.get()));
 }
 
 bool OCSP::compareResponderCert(const X509Cert &cert) const
@@ -187,17 +191,19 @@ void OCSP::verifyResponse(const X509Cert &cert) const
         THROW("Failed to verify OCSP response.");
 
     tm tm = producedAt();
-    time_t t = util::date::mkgmtime(tm);
-    SCOPE(X509_STORE, store, X509CertStore::createStore(X509CertStore::OCSP, &t));
-    STACK_OF(X509) *stack = sk_X509_new_null();
+    // Some OCSP-s do not have certificates in response and stack is used for finding certificate for this
+    auto stack = make_unique_ptr(sk_X509_new_null(), [](auto *sk) { sk_X509_free(sk); });
     for(const X509Cert &i: X509CertStore::instance()->certs(X509CertStore::OCSP))
     {
         if(compareResponderCert(i))
-            sk_X509_push(stack, i.handle());
+            sk_X509_push(stack.get(), i.handle());
     }
-    int result = OCSP_basic_verify(basic.get(), stack, store.get(), OCSP_NOCHECKS);
-    sk_X509_free(stack);
-    if(result != 1)
+    auto store = X509CertStore::createStore(X509CertStore::OCSP, tm);
+#if OPENSSL_VERSION_NUMBER < 0x30000000L
+    if(OCSP_basic_verify(basic.get(), stack.get(), store.get(), OCSP_NOCHECKS) != 1)
+#else
+    if(OCSP_basic_verify(basic.get(), stack.get(), store.get(), OCSP_NOCHECKS | OCSP_PARTIAL_CHAIN) != 1)
+#endif
     {
         unsigned long err = ERR_get_error();
         if(ERR_GET_LIB(err) == ERR_LIB_OCSP &&
@@ -259,17 +265,18 @@ void OCSP::verifyResponse(const X509Cert &cert) const
  */
 vector<unsigned char> OCSP::nonce() const
 {
+    vector<unsigned char> nonce;
     if(!basic)
-        return {};
+        return nonce;
     int resp_idx = OCSP_BASICRESP_get_ext_by_NID(basic.get(), NID_id_pkix_OCSP_Nonce, -1);
     if(resp_idx < 0)
-        return {};
+        return nonce;
     X509_EXTENSION *ext = OCSP_BASICRESP_get_ext(basic.get(), resp_idx);
     if(!ext)
-        return {};
+        return nonce;
 
     ASN1_OCTET_STRING *value = X509_EXTENSION_get_data(ext);
-    vector<unsigned char> nonce(value->data, value->data + value->length);
+    nonce.assign(value->data, std::next(value->data, value->length));
     //OpenSSL OCSP created messages NID_id_pkix_OCSP_Nonce field is DER encoded twice, not a problem with java impl
     //XXX: UglyHackTM check if nonceAsn1 contains ASN1_OCTET_STRING
     //XXX: if first 2 bytes seem to be beginning of DER ASN1_OCTET_STRING then remove them
@@ -281,9 +288,9 @@ vector<unsigned char> OCSP::nonce() const
 
 tm OCSP::producedAt() const
 {
-    if(!basic)
-        return {};
     tm tm {};
+    if(!basic)
+        return tm;
     ASN1_TIME_to_tm(OCSP_resp_get0_produced_at(basic.get()), &tm);
     return tm;
 }
diff --git a/src/crypto/OCSP.h b/src/crypto/OCSP.h
index 63c716c10..bbfd7f166 100644
--- a/src/crypto/OCSP.h
+++ b/src/crypto/OCSP.h
@@ -19,7 +19,8 @@
 
 #pragma once
 
-#include <memory>
+#include "util/memory.h"
+
 #include <string>
 #include <vector>
 
@@ -51,7 +52,7 @@ namespace digidoc
       private:
           bool compareResponderCert(const X509Cert &cert) const;
 
-          std::shared_ptr<OCSP_RESPONSE> resp;
-          std::shared_ptr<OCSP_BASICRESP> basic;
+          unique_free_t<OCSP_RESPONSE> resp;
+          unique_free_t<OCSP_BASICRESP> basic;
     };
 }
diff --git a/src/crypto/OpenSSLHelpers.h b/src/crypto/OpenSSLHelpers.h
index 1a5253e23..3c87757c0 100644
--- a/src/crypto/OpenSSLHelpers.h
+++ b/src/crypto/OpenSSLHelpers.h
@@ -21,9 +21,7 @@
 
 #include "Exception.h"
 #include "util/log.h"
-
-#include <memory>
-#include <sstream>
+#include "util/memory.h"
 
 #include <openssl/err.h>
 
@@ -34,7 +32,7 @@
 namespace digidoc
 {
 
-#define SCOPE_PTR_FREE(TYPE, DATA, FREE) std::unique_ptr<TYPE,decltype(&FREE)>(static_cast<TYPE*>(DATA), FREE)
+#define SCOPE_PTR_FREE(TYPE, DATA, FREE) make_unique_ptr(DATA, FREE)
 #define SCOPE_PTR(TYPE, DATA) SCOPE_PTR_FREE(TYPE, DATA, TYPE##_free)
 #define SCOPE(TYPE, VAR, DATA) auto VAR = SCOPE_PTR_FREE(TYPE, DATA, TYPE##_free)
 
@@ -42,14 +40,15 @@ template<class T, typename Func>
 [[nodiscard]]
 inline std::vector<unsigned char> i2d(T *obj, Func func)
 {
+    std::vector<unsigned char> result;
     if(!obj)
-        return {};
+        return result;
     int size = func(obj, nullptr);
     if(size <= 0)
-        return {};
-    std::vector<unsigned char> result(size_t(size), 0);
+        return result;
+    result.resize(size_t(size), 0);
     if(unsigned char *p = result.data(); func(obj, &p) != size)
-        return {};
+        result.clear();
     return result;
 }
 
diff --git a/src/crypto/TS.cpp b/src/crypto/TS.cpp
index 89cebccd8..5dfb3a1b1 100644
--- a/src/crypto/TS.cpp
+++ b/src/crypto/TS.cpp
@@ -23,6 +23,7 @@
 #include "Container.h"
 #include "Exception.h"
 #include "crypto/Connect.h"
+#include "crypto/Digest.h"
 #include "crypto/OpenSSLHelpers.h"
 #include "crypto/X509CertStore.h"
 #include "util/DateTime.h"
@@ -56,15 +57,15 @@ void *OPENSSL_memdup(const void *data, size_t size)
 #endif
 
 TS::TS(const Digest &digest, const std::string &userAgent)
+    : d(nullptr, PKCS7_free)
+    , cms(nullptr, CMS_ContentInfo_free)
 {
     auto req = SCOPE_PTR(TS_REQ, TS_REQ_new());
     TS_REQ_set_version(req.get(), 1);
     TS_REQ_set_cert_req(req.get(), 1);
 
     auto algo = SCOPE_PTR(X509_ALGOR, X509_ALGOR_new());
-    algo->algorithm = OBJ_nid2obj(Digest::toMethod(digest.uri()));
-    algo->parameter = ASN1_TYPE_new();
-    algo->parameter->type = V_ASN1_NULL;
+    X509_ALGOR_set0(algo.get(), OBJ_nid2obj(Digest::toMethod(digest.uri())), V_ASN1_NULL, nullptr);
 
     auto msg_imprint = SCOPE_PTR(TS_MSG_IMPRINT, TS_MSG_IMPRINT_new());
     TS_MSG_IMPRINT_set_algo(msg_imprint.get(), algo.get());
@@ -82,8 +83,7 @@ TS::TS(const Digest &digest, const std::string &userAgent)
 
     auto nonce = SCOPE_PTR(ASN1_INTEGER, ASN1_INTEGER_new());
     ASN1_STRING_set(nonce.get(), nullptr, 20);
-    nonce->data[0] = 0;
-    while(nonce->data[0] == 0) // Make sure that first byte is not 0x00
+    for(nonce->data[0] = 0; nonce->data[0] == 0;) // Make sure that first byte is not 0x00
         RAND_bytes(nonce->data, nonce->length);
     TS_REQ_set_nonce(req.get(), nonce.get());
 
@@ -119,15 +119,20 @@ TS::TS(const Digest &digest, const std::string &userAgent)
     if(TS_RESP_verify_response(ctx.get(), resp.get()) != 1)
         THROW_OPENSSLEXCEPTION("Failed to verify TS response.");
 
-    d.reset(PKCS7_dup(TS_RESP_get_token(resp.get())), PKCS7_free);
+    d.reset(PKCS7_dup(TS_RESP_get_token(resp.get())));
     DEBUG("TSA time %s", util::date::to_string(time()).c_str());
 }
 
 TS::TS(const unsigned char *data, size_t size)
+    : d(nullptr, PKCS7_free)
+    , cms(nullptr, [](CMS_ContentInfo *contentInfo) {
+        CMS_ContentInfo_free(contentInfo);
+        ERR_clear_error();
+    })
 {
     if(size == 0)
         return;
-    d.reset(d2i_PKCS7(nullptr, &data, long(size)), PKCS7_free);
+    d.reset(d2i_PKCS7(nullptr, &data, long(size)));
 #ifndef OPENSSL_NO_CMS
     if(d)
         return;
@@ -139,10 +144,7 @@ TS::TS(const unsigned char *data, size_t size)
      *
      * If PKCS7 wrapped TimeStamp parsing fails, try with CMS wrapping
      */
-    cms.reset(d2i_CMS_ContentInfo(nullptr, &data, long(size)), [](CMS_ContentInfo *contentInfo) {
-        CMS_ContentInfo_free(contentInfo);
-        ERR_clear_error();
-    });
+    cms.reset(d2i_CMS_ContentInfo(nullptr, &data, long(size)));
     if(!cms || OBJ_obj2nid(CMS_get0_eContentType(cms.get())) != NID_id_smime_ct_TSTInfo)
         cms.reset();
 
@@ -152,22 +154,18 @@ TS::TS(const unsigned char *data, size_t size)
 
 X509Cert TS::cert() const
 {
-    using sk_X509_free_t = void (*)(STACK_OF(X509) *);
-    unique_ptr<STACK_OF(X509), sk_X509_free_t> signers = [&] {
-        if(d && PKCS7_type_is_signed(d.get()))
-            return unique_ptr<STACK_OF(X509), sk_X509_free_t>(PKCS7_get0_signers(d.get(), nullptr, 0),
-                [](STACK_OF(X509) *stack) { sk_X509_free(stack); });
+    unique_free_t<STACK_OF(X509)> signers(nullptr, nullptr);
+    if(d && PKCS7_type_is_signed(d.get()))
+        signers = {PKCS7_get0_signers(d.get(), nullptr, 0),
+            [](STACK_OF(X509) *stack) { sk_X509_free(stack); }};
 #ifndef OPENSSL_NO_CMS
-        if(cms)
-            return unique_ptr<STACK_OF(X509), sk_X509_free_t>(CMS_get1_certs(cms.get()),
-                [](STACK_OF(X509) *stack) { sk_X509_pop_free(stack, X509_free); });
+    if(!signers && cms)
+        signers = {CMS_get1_certs(cms.get()),
+            [](STACK_OF(X509) *stack) { sk_X509_pop_free(stack, X509_free); }};
 #endif
-        return unique_ptr<STACK_OF(X509), sk_X509_free_t>(nullptr, nullptr);
-    }();
-
-    if(!signers || sk_X509_num(signers.get()) != 1)
-        return X509Cert();
-    return X509Cert(sk_X509_value(signers.get(), 0));
+    if(signers && sk_X509_num(signers.get()) == 1)
+        return X509Cert(sk_X509_value(signers.get(), 0));
+    return X509Cert();
 }
 
 auto TS::tstInfo() const
@@ -177,8 +175,8 @@ auto TS::tstInfo() const
 #ifndef OPENSSL_NO_CMS
     if(cms)
     {
-        auto out = SCOPE_PTR(BIO, CMS_dataInit(cms.get(), nullptr));
-        return SCOPE_PTR(TS_TST_INFO, d2i_TS_TST_INFO_bio(out.get(), nullptr));
+        if(auto out = SCOPE_PTR(BIO, CMS_dataInit(cms.get(), nullptr)))
+            return SCOPE_PTR(TS_TST_INFO, d2i_TS_TST_INFO_bio(out.get(), nullptr));
     }
 #endif
     return SCOPE_PTR(TS_TST_INFO, nullptr);
@@ -216,8 +214,7 @@ string TS::serial() const
 
     if(auto bn = SCOPE_PTR_FREE(BIGNUM, ASN1_INTEGER_to_BN(TS_TST_INFO_get_serial(info.get()), nullptr), BN_free))
     {
-        auto openssl_free = [](char *data) { OPENSSL_free(data); };
-        if(auto str = unique_ptr<char,decltype(openssl_free)>(BN_bn2dec(bn.get()), openssl_free))
+        if(auto str = make_unique_ptr(BN_bn2dec(bn.get()), [](char *data) { OPENSSL_free(data); }))
             return str.get();
     }
     return {};
@@ -234,15 +231,8 @@ tm TS::time() const
 void TS::verify(const vector<unsigned char> &digest)
 {
     tm tm = time();
-    time_t t = util::date::mkgmtime(tm);
-    auto store = SCOPE_PTR(X509_STORE, X509CertStore::createStore(X509CertStore::TSA, &t));
+    auto store = X509CertStore::createStore(X509CertStore::TSA, tm);
     X509CertStore::instance()->activate(cert());
-    auto csc = SCOPE_PTR(X509_STORE_CTX, X509_STORE_CTX_new());
-    if (!csc)
-        THROW_OPENSSLEXCEPTION("Failed to create X509_STORE_CTX");
-    if(!X509_STORE_CTX_init(csc.get(), store.get(), nullptr, nullptr))
-        THROW_OPENSSLEXCEPTION("Failed to init X509_STORE_CTX");
-
     if(d)
     {
         auto ctx = SCOPE_PTR(TS_VERIFY_CTX, TS_VERIFY_CTX_new());
diff --git a/src/crypto/TS.h b/src/crypto/TS.h
index 16186a411..f09c9f657 100644
--- a/src/crypto/TS.h
+++ b/src/crypto/TS.h
@@ -19,12 +19,16 @@
 
 #pragma once
 
-#include "Digest.h"
+#include "util/memory.h"
+
+#include <string>
+#include <vector>
 
 using PKCS7 = struct pkcs7_st;
 using CMS_ContentInfo = struct CMS_ContentInfo_st;
 namespace digidoc {
 
+class Digest;
 class X509Cert;
 
 class TS
@@ -46,8 +50,8 @@ class TS
 
 private:
     auto tstInfo() const;
-    std::shared_ptr<PKCS7> d;
-    std::shared_ptr<CMS_ContentInfo> cms;
+    unique_free_t<PKCS7> d;
+    unique_free_t<CMS_ContentInfo> cms;
 };
 
 }
diff --git a/src/crypto/X509CertStore.cpp b/src/crypto/X509CertStore.cpp
index b0dbf0dcc..9485ee61e 100644
--- a/src/crypto/X509CertStore.cpp
+++ b/src/crypto/X509CertStore.cpp
@@ -132,28 +132,19 @@ X509Cert X509CertStore::issuerFromAIA(const X509Cert &cert)
     return X509Cert((const unsigned char*)result.content.c_str(), result.content.size());
 }
 
-X509_STORE* X509CertStore::createStore(const Type &type, const time_t *t)
+unique_free_t<X509_STORE> X509CertStore::createStore(const Type &type, tm &tm)
 {
     SCOPE(X509_STORE, store, X509_STORE_new());
     if (!store)
         THROW_OPENSSLEXCEPTION("Failed to create X509_STORE_CTX");
-
-    if(type == CA)
-        X509_STORE_set_verify_cb(store.get(), [](int ok, X509_STORE_CTX *ctx) -> int { return validate(ok, ctx, CA); });
-    else if(type == OCSP)
-        X509_STORE_set_verify_cb(store.get(), [](int ok, X509_STORE_CTX *ctx) -> int { return validate(ok, ctx, OCSP); });
-    else if(type == TSA)
-        X509_STORE_set_verify_cb(store.get(), [](int ok, X509_STORE_CTX *ctx) -> int { return validate(ok, ctx, TSA); });
-
-    if(t)
-    {
-        X509_VERIFY_PARAM_set_time(X509_STORE_get0_param(store.get()), *t);
-        X509_STORE_set_flags(store.get(), X509_V_FLAG_USE_CHECK_TIME);
-    }
-    return store.release();
+    X509_STORE_set_verify_cb(store.get(), X509CertStore::validate);
+    X509_STORE_set_ex_data(store.get(), 0, const_cast<Type*>(&type));
+    X509_STORE_set_flags(store.get(), X509_V_FLAG_USE_CHECK_TIME | X509_V_FLAG_PARTIAL_CHAIN);
+    X509_VERIFY_PARAM_set_time(X509_STORE_get0_param(store.get()), util::date::mkgmtime(tm));
+    return store;
 }
 
-int X509CertStore::validate(int ok, X509_STORE_CTX *ctx, const Type &type)
+int X509CertStore::validate(int ok, X509_STORE_CTX *ctx)
 {
     switch(X509_STORE_CTX_get_error(ctx))
     {
@@ -167,39 +158,33 @@ int X509CertStore::validate(int ok, X509_STORE_CTX *ctx, const Type &type)
     default: return ok;
     }
 
+    auto *type = static_cast<Type*>(X509_STORE_get_ex_data(X509_STORE_CTX_get0_store(ctx), 0));
     X509 *x509 = X509_STORE_CTX_get0_cert(ctx);
+    auto current = util::date::to_string(X509_VERIFY_PARAM_get_time(X509_STORE_CTX_get0_param(ctx)));
     for(const TSL::Service &s: *instance()->d)
     {
-        if(type.find(s.type) == type.cend())
+        if(type->find(s.type) == type->cend()) // correct service type
             continue;
         if(none_of(s.certs, [&](const X509Cert &issuer) {
-                if(issuer == x509)
+                if(issuer == x509) // certificate is listed by service
                     return true;
-                if(X509_check_issued(issuer.handle(), x509) != X509_V_OK)
+                if(X509_check_issued(issuer.handle(), x509) != X509_V_OK) // certificate is issued by service
                     return false;
                 SCOPE(EVP_PKEY, pub, X509_get_pubkey(issuer.handle()));
-                if(X509_verify(x509, pub.get()) == 1)
+                if(X509_verify(x509, pub.get()) == 1) // certificate is signed by service
                     return true;
                 ERR_clear_error();
                 return false;
-            }))
+            })) // certificate is trusted by service
             continue;
-        if(s.validity.empty())
-            continue;
-        X509_STORE_CTX_set_ex_data(ctx, 0, const_cast<TSL::Qualifiers*>(&s.validity.begin()->second));
-        X509_VERIFY_PARAM *param = X509_STORE_CTX_get0_param(ctx);
-        if(!(X509_VERIFY_PARAM_get_flags(param) & X509_V_FLAG_USE_CHECK_TIME) || s.validity.empty())
-            return 1;
-        auto current = util::date::to_string(X509_VERIFY_PARAM_get_time(param));
         for(auto i = s.validity.crbegin(), end = s.validity.crend(); i != end; ++i)
         {
-            if(current >= i->first)
-            {
-                if(!i->second.has_value())
-                    break;
-                X509_STORE_CTX_set_ex_data(ctx, 0, const_cast<TSL::Qualifiers*>(&i->second));
-                return 1;
-            }
+            if(current < i->first) // Search older status
+                continue;
+            if(!i->second.has_value()) // Has revoked
+                break;
+            X509_STORE_CTX_set_ex_data(ctx, 0, const_cast<TSL::Qualifiers*>(&i->second));
+            return 1;
         }
     }
     return ok;
@@ -209,13 +194,12 @@ int X509CertStore::validate(int ok, X509_STORE_CTX *ctx, const Type &type)
  * Check if X509Cert is signed by trusted issuer
  * @throw Exception if error
  */
-bool X509CertStore::verify(const X509Cert &cert, bool noqscd) const
+bool X509CertStore::verify(const X509Cert &cert, bool noqscd, tm validation_time) const
 {
     activate(cert);
-    tm tm{};
-    ASN1_TIME_to_tm(X509_get0_notBefore(cert.handle()), &tm);
-    time_t time = util::date::mkgmtime(tm);
-    SCOPE(X509_STORE, store, createStore(X509CertStore::CA, &time));
+    if(util::date::is_empty(validation_time))
+        ASN1_TIME_to_tm(X509_get0_notBefore(cert.handle()), &validation_time);
+    auto store = createStore(X509CertStore::CA, validation_time);
     SCOPE(X509_STORE_CTX, csc, X509_STORE_CTX_new());
     if(!X509_STORE_CTX_init(csc.get(), store.get(), cert.handle(), nullptr))
         THROW_OPENSSLEXCEPTION("Failed to init X509_STORE_CTX");
diff --git a/src/crypto/X509CertStore.h b/src/crypto/X509CertStore.h
index 8221f5093..61c6e724c 100644
--- a/src/crypto/X509CertStore.h
+++ b/src/crypto/X509CertStore.h
@@ -21,7 +21,8 @@
 
 #include "../Exports.h"
 
-#include <memory>
+#include "util/memory.h"
+
 #include <set>
 #include <string>
 #include <vector>
@@ -47,15 +48,15 @@ namespace digidoc
         std::vector<X509Cert> certs(const Type &type) const;
         X509Cert findIssuer(const X509Cert &cert, const Type &type) const;
         static X509Cert issuerFromAIA(const X509Cert &cert);
-        static X509_STORE* createStore(const Type &type, const time_t *t = nullptr);
-        bool verify(const X509Cert &cert, bool qscd) const;
+        static unique_free_t<X509_STORE> createStore(const Type &type, tm &tm);
+        bool verify(const X509Cert &cert, bool noqscd, tm validation_time = {}) const;
 
     private:
         X509CertStore();
         ~X509CertStore();
         DISABLE_COPY(X509CertStore);
 
-        static int validate(int ok, X509_STORE_CTX *ctx, const Type &type);
+        static int validate(int ok, X509_STORE_CTX *ctx);
         class Private;
         std::unique_ptr<Private> d;
     };
diff --git a/src/util/DateTime.cpp b/src/util/DateTime.cpp
index 508c2cbab..bf949e89c 100644
--- a/src/util/DateTime.cpp
+++ b/src/util/DateTime.cpp
@@ -38,7 +38,20 @@ struct tm date::gmtime(time_t t)
     return tm;
 }
 
-time_t date::mkgmtime(struct tm &t)
+bool date::is_empty(const tm &t)
+{
+    return t.tm_sec == 0 &&
+        t.tm_min == 0 &&
+        t.tm_hour == 0 &&
+        t.tm_mday == 0 &&
+        t.tm_mon == 0 &&
+        t.tm_year == 0 &&
+        t.tm_wday == 0 &&
+        t.tm_yday == 0 &&
+        t.tm_isdst == 0;
+}
+
+time_t date::mkgmtime(tm &t)
 {
 #ifdef _WIN32
     return _mkgmtime(&t);
@@ -54,11 +67,8 @@ string date::to_string(time_t t)
 
 string date::to_string(const tm &date)
 {
-    static const tm zero{};
-    if(memcmp(&zero, &date, sizeof(zero)) == 0)
-        return {};
     string result(20, 0);
     if(strftime(result.data(), result.size() + 1, "%Y-%m-%dT%H:%M:%SZ", &date) == 0)
-        return {};
+        result.clear();
     return result;
 }
diff --git a/src/util/DateTime.h b/src/util/DateTime.h
index 018eaefa8..a5260a796 100644
--- a/src/util/DateTime.h
+++ b/src/util/DateTime.h
@@ -30,7 +30,8 @@ namespace digidoc
         {
         public:
             static struct tm gmtime(time_t t);
-            static time_t mkgmtime(struct tm &t);
+            static bool is_empty(const tm &t);
+            static time_t mkgmtime(tm &t);
             static std::string to_string(time_t t);
             static std::string to_string(const tm &date);
         };
diff --git a/src/util/memory.h b/src/util/memory.h
new file mode 100644
index 000000000..39f1a0516
--- /dev/null
+++ b/src/util/memory.h
@@ -0,0 +1,46 @@
+/*
+ * libdigidocpp
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#pragma once
+
+#include <memory>
+
+template <class T>
+using unique_free_t = std::unique_ptr<T, void(*)(T*)>;
+
+template<class T, class U>
+[[nodiscard]]
+constexpr unique_free_t<T> make_unique_ptr(U *p, void (*d)(T*)) noexcept
+{
+    return {static_cast<T*>(p), d};
+}
+
+template<class T>
+[[nodiscard]]
+constexpr auto make_unique_ptr(nullptr_t, void (*d)(T*)) noexcept
+{
+    return make_unique_ptr<T, T>(nullptr, d);
+}
+
+template<class T, typename D>
+[[nodiscard]]
+constexpr std::unique_ptr<T, D> make_unique_ptr(T *p, D d) noexcept
+{
+    return {p, std::forward<D>(d)};
+}