if (ENABLE_SSL)
  if (STATIC_BUILD OR NOT USE_SYSTEM_OPENSSL)
    # WARNING - We had to repack the upstream ".tar.gz" file to a ZIP
    # file, as the upstream distribution ships symbolic links that are
    # not always properly handled when uncompressing on Windows.

    SET(OPENSSL_SOURCES_DIR ${CMAKE_BINARY_DIR}/openssl-1.0.2d)
    SET(OPENSSL_URL "http://www.orthanc-server.com/downloads/third-party/openssl-1.0.2d.zip")
    SET(OPENSSL_MD5 "4b2ac15fc6db17f3dadc54482d3eee85")

    if (IS_DIRECTORY "${OPENSSL_SOURCES_DIR}")
      set(FirstRun OFF)
    else()
      set(FirstRun ON)
    endif()

    DownloadPackage(${OPENSSL_MD5} ${OPENSSL_URL} "${OPENSSL_SOURCES_DIR}")

    add_definitions(
      -DOPENSSL_THREADS
      -DOPENSSL_IA32_SSE2
      -DOPENSSL_NO_ASM
      -DOPENSSL_NO_DYNAMIC_ENGINE
      -DNO_WINDOWS_BRAINDEATH

      -DOPENSSL_NO_BF 
      -DOPENSSL_NO_CAMELLIA
      -DOPENSSL_NO_CAST 
      -DOPENSSL_NO_EC_NISTP_64_GCC_128
      -DOPENSSL_NO_GMP
      -DOPENSSL_NO_GOST
      -DOPENSSL_NO_HW
      -DOPENSSL_NO_JPAKE
      -DOPENSSL_NO_IDEA
      -DOPENSSL_NO_KRB5 
      -DOPENSSL_NO_MD2 
      -DOPENSSL_NO_MDC2 
      -DOPENSSL_NO_MD4
      -DOPENSSL_NO_RC2 
      -DOPENSSL_NO_RC4 
      -DOPENSSL_NO_RC5 
      -DOPENSSL_NO_RFC3779
      -DOPENSSL_NO_SCTP
      -DOPENSSL_NO_STORE
      -DOPENSSL_NO_SEED
      -DOPENSSL_NO_WHIRLPOOL
      -DOPENSSL_NO_RIPEMD
      )

    include_directories(
      ${OPENSSL_SOURCES_DIR}
      ${OPENSSL_SOURCES_DIR}/crypto
      ${OPENSSL_SOURCES_DIR}/crypto/asn1
      ${OPENSSL_SOURCES_DIR}/crypto/modes
      ${OPENSSL_SOURCES_DIR}/crypto/evp
      ${OPENSSL_SOURCES_DIR}/include
      )

    set(OPENSSL_SOURCES_SUBDIRS
      ${OPENSSL_SOURCES_DIR}/crypto
      ${OPENSSL_SOURCES_DIR}/crypto/aes
      ${OPENSSL_SOURCES_DIR}/crypto/asn1
      ${OPENSSL_SOURCES_DIR}/crypto/bio
      ${OPENSSL_SOURCES_DIR}/crypto/bn
      ${OPENSSL_SOURCES_DIR}/crypto/buffer
      ${OPENSSL_SOURCES_DIR}/crypto/cmac
      ${OPENSSL_SOURCES_DIR}/crypto/cms
      ${OPENSSL_SOURCES_DIR}/crypto/comp
      ${OPENSSL_SOURCES_DIR}/crypto/conf
      ${OPENSSL_SOURCES_DIR}/crypto/des
      ${OPENSSL_SOURCES_DIR}/crypto/dh
      ${OPENSSL_SOURCES_DIR}/crypto/dsa
      ${OPENSSL_SOURCES_DIR}/crypto/dso
      ${OPENSSL_SOURCES_DIR}/crypto/engine
      ${OPENSSL_SOURCES_DIR}/crypto/err
      ${OPENSSL_SOURCES_DIR}/crypto/evp
      ${OPENSSL_SOURCES_DIR}/crypto/hmac
      ${OPENSSL_SOURCES_DIR}/crypto/lhash
      ${OPENSSL_SOURCES_DIR}/crypto/md5
      ${OPENSSL_SOURCES_DIR}/crypto/modes
      ${OPENSSL_SOURCES_DIR}/crypto/objects
      ${OPENSSL_SOURCES_DIR}/crypto/ocsp
      ${OPENSSL_SOURCES_DIR}/crypto/pem
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs12
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs7
      ${OPENSSL_SOURCES_DIR}/crypto/pqueue
      ${OPENSSL_SOURCES_DIR}/crypto/rand
      ${OPENSSL_SOURCES_DIR}/crypto/rsa
      ${OPENSSL_SOURCES_DIR}/crypto/sha
      ${OPENSSL_SOURCES_DIR}/crypto/srp
      ${OPENSSL_SOURCES_DIR}/crypto/stack
      ${OPENSSL_SOURCES_DIR}/crypto/ts
      ${OPENSSL_SOURCES_DIR}/crypto/txt_db
      ${OPENSSL_SOURCES_DIR}/crypto/ui
      ${OPENSSL_SOURCES_DIR}/crypto/x509
      ${OPENSSL_SOURCES_DIR}/crypto/x509v3
      ${OPENSSL_SOURCES_DIR}/ssl
      )

    if (ENABLE_PKCS11)
      list(APPEND OPENSSL_SOURCES_SUBDIRS
        # EC, ECDH and ECDSA are necessary for PKCS11
        ${OPENSSL_SOURCES_DIR}/crypto/ec
        ${OPENSSL_SOURCES_DIR}/crypto/ecdh
        ${OPENSSL_SOURCES_DIR}/crypto/ecdsa
        )
    else()
      add_definitions(
        -DOPENSSL_NO_EC
        -DOPENSSL_NO_ECDH
        -DOPENSSL_NO_ECDSA
        )
    endif()

    foreach(d ${OPENSSL_SOURCES_SUBDIRS})
      AUX_SOURCE_DIRECTORY(${d} OPENSSL_SOURCES)
    endforeach()

    list(REMOVE_ITEM OPENSSL_SOURCES
      ${OPENSSL_SOURCES_DIR}/crypto/LPdir_unix.c
      ${OPENSSL_SOURCES_DIR}/crypto/LPdir_vms.c
      ${OPENSSL_SOURCES_DIR}/crypto/LPdir_win.c
      ${OPENSSL_SOURCES_DIR}/crypto/LPdir_win32.c
      ${OPENSSL_SOURCES_DIR}/crypto/LPdir_wince.c
      ${OPENSSL_SOURCES_DIR}/crypto/armcap.c
      ${OPENSSL_SOURCES_DIR}/crypto/bf/bfs.cpp
      ${OPENSSL_SOURCES_DIR}/crypto/bio/bss_rtcp.c
      ${OPENSSL_SOURCES_DIR}/crypto/bn/exp.c
      ${OPENSSL_SOURCES_DIR}/crypto/conf/cnf_save.c
      ${OPENSSL_SOURCES_DIR}/crypto/conf/test.c
      ${OPENSSL_SOURCES_DIR}/crypto/des/des.c
      ${OPENSSL_SOURCES_DIR}/crypto/des/des3s.cpp
      ${OPENSSL_SOURCES_DIR}/crypto/des/des_opts.c
      ${OPENSSL_SOURCES_DIR}/crypto/des/dess.cpp
      ${OPENSSL_SOURCES_DIR}/crypto/des/read_pwd.c
      ${OPENSSL_SOURCES_DIR}/crypto/des/speed.c
      ${OPENSSL_SOURCES_DIR}/crypto/evp/e_dsa.c
      ${OPENSSL_SOURCES_DIR}/crypto/evp/m_ripemd.c
      ${OPENSSL_SOURCES_DIR}/crypto/lhash/lh_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/md5/md5s.cpp
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs7/bio_ber.c
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs7/pk7_enc.c
      ${OPENSSL_SOURCES_DIR}/crypto/ppccap.c
      ${OPENSSL_SOURCES_DIR}/crypto/rand/randtest.c
      ${OPENSSL_SOURCES_DIR}/crypto/s390xcap.c
      ${OPENSSL_SOURCES_DIR}/crypto/sparcv9cap.c
      ${OPENSSL_SOURCES_DIR}/crypto/x509v3/tabtest.c
      ${OPENSSL_SOURCES_DIR}/crypto/x509v3/v3conf.c
      ${OPENSSL_SOURCES_DIR}/ssl/ssl_task.c
      ${OPENSSL_SOURCES_DIR}/crypto/LPdir_nyi.c
      ${OPENSSL_SOURCES_DIR}/crypto/aes/aes_x86core.c
      ${OPENSSL_SOURCES_DIR}/crypto/bio/bss_dgram.c
      ${OPENSSL_SOURCES_DIR}/crypto/bn/bntest.c
      ${OPENSSL_SOURCES_DIR}/crypto/bn/expspeed.c
      ${OPENSSL_SOURCES_DIR}/crypto/bn/exptest.c
      ${OPENSSL_SOURCES_DIR}/crypto/engine/enginetest.c
      ${OPENSSL_SOURCES_DIR}/crypto/evp/evp_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/hmac/hmactest.c
      ${OPENSSL_SOURCES_DIR}/crypto/md5/md5.c
      ${OPENSSL_SOURCES_DIR}/crypto/md5/md5test.c
      ${OPENSSL_SOURCES_DIR}/crypto/o_dir_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs7/dec.c
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs7/enc.c
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs7/sign.c
      ${OPENSSL_SOURCES_DIR}/crypto/pkcs7/verify.c
      ${OPENSSL_SOURCES_DIR}/crypto/rsa/rsa_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/sha/sha.c
      ${OPENSSL_SOURCES_DIR}/crypto/sha/sha1.c
      ${OPENSSL_SOURCES_DIR}/crypto/sha/sha1t.c
      ${OPENSSL_SOURCES_DIR}/crypto/sha/sha1test.c
      ${OPENSSL_SOURCES_DIR}/crypto/sha/sha256t.c
      ${OPENSSL_SOURCES_DIR}/crypto/sha/sha512t.c
      ${OPENSSL_SOURCES_DIR}/crypto/sha/shatest.c
      ${OPENSSL_SOURCES_DIR}/crypto/srp/srptest.c

      ${OPENSSL_SOURCES_DIR}/crypto/bn/divtest.c
      ${OPENSSL_SOURCES_DIR}/crypto/bn/bnspeed.c
      ${OPENSSL_SOURCES_DIR}/crypto/des/destest.c
      ${OPENSSL_SOURCES_DIR}/crypto/dh/p192.c
      ${OPENSSL_SOURCES_DIR}/crypto/dh/p512.c
      ${OPENSSL_SOURCES_DIR}/crypto/dh/p1024.c
      ${OPENSSL_SOURCES_DIR}/crypto/des/rpw.c
      ${OPENSSL_SOURCES_DIR}/ssl/ssltest.c
      ${OPENSSL_SOURCES_DIR}/crypto/dsa/dsagen.c
      ${OPENSSL_SOURCES_DIR}/crypto/dsa/dsatest.c
      ${OPENSSL_SOURCES_DIR}/crypto/dh/dhtest.c
      ${OPENSSL_SOURCES_DIR}/crypto/pqueue/pq_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/des/ncbc_enc.c

      ${OPENSSL_SOURCES_DIR}/crypto/evp/evp_extra_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/evp/verify_extra_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/x509/verify_extra_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/x509v3/v3prin.c
      ${OPENSSL_SOURCES_DIR}/crypto/x509v3/v3nametest.c
      ${OPENSSL_SOURCES_DIR}/crypto/constant_time_test.c
      ${OPENSSL_SOURCES_DIR}/crypto/ec/ecp_nistz256_table.c

      ${OPENSSL_SOURCES_DIR}/ssl/heartbeat_test.c
      )


    if ("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
      set_source_files_properties(
        ${OPENSSL_SOURCES}
        PROPERTIES COMPILE_DEFINITIONS
        "OPENSSL_SYSNAME_WIN32;SO_WIN32;WIN32_LEAN_AND_MEAN;L_ENDIAN")

    elseif ("${CMAKE_SYSTEM_VERSION}" STREQUAL "LinuxStandardBase")
      execute_process(
        COMMAND ${PATCH_EXECUTABLE} -N ui_openssl.c -i ${ORTHANC_ROOT}/Resources/Patches/openssl-lsb.diff
        WORKING_DIRECTORY ${OPENSSL_SOURCES_DIR}/crypto/ui
        RESULT_VARIABLE Failure
        )

      if (Failure AND FirstRun)
        message(FATAL_ERROR "Error while patching a file")
      endif()
    endif()

    source_group(ThirdParty\\OpenSSL REGULAR_EXPRESSION ${OPENSSL_SOURCES_DIR}/.*)

  else()
    include(FindOpenSSL)

    if (NOT ${OPENSSL_FOUND})
      message(FATAL_ERROR "Unable to find OpenSSL")
    endif()

    include_directories(${OPENSSL_INCLUDE_DIR})
    link_libraries(${OPENSSL_LIBRARIES})
  endif()
endif()