Connect:Direct Secure Plus Considerations

Review the following Connect:Direct® Secure Plus considerations before configuring the product:

  • Support for the TLS 1.1 and TLS 1.2 protocols require certain version and release levels, as well as PTF service to use those protocols. See the Program Directory for detailed information on these requirements.
  • Support for TLS 1.3 requires z/OS V2R4 or greater release or version
  • TLS 1.3 is not supported in FIPS Mode

  • TLS 1.3 only support cipher suites TLS_AES_128_GCM_SHA256 (1301) and TLS_AES_256_GCM_SHA384 (1302)

  • TLS1.3 does not support certificates with SHA1 & SHA224 signature algorithms and RSA Key Length less than 2048. Also, DSA certificates not supported by TLS1.3
  • Elliptic curve (key_shares / groups) supported by TLS1.3
    • X448 (0030)
    • X25519 (0029)
    • SECP521R1 (0025)
    • SECP384R1 (0024)
    • SECP256R1 (0023)
  • Certificates supported by TLS 1.3
    Certificate type Preferred Signature Algorithm
    RSA certificate with a signature algorithm of RSA with SHA-1 (Key sizes 2048 and larger 0804 - SHA-256 with RSASSA-PSS
    RSA certificate with a signature algorithm of RSA with SHA-256 (Key sizes 2048 and larger 0804 - SHA-256 with RSASSA-PSS

    RSA certificate with a signature algorithm of RSASSA-PSS with SHA-256 (Key sizes 2048 and larger)

    0804 - SHA-256 with RSASSA-PSS
    RSA certificate with a signature algorithm of RSA with SHA-384 (Key sizes 2048 and larger) 0805 – SHA-384 with RSASSA-PSS

    RSA certificate with a signature algorithm of RSASSA-PSS with SHA-384 (Key sizes 2048 and larger)

    0805 – SHA-384 with RSASSA-PSS
    RSA certificate with a signature algorithm of RSA with SHA-384 (Key sizes 2048 and larger) 0806 – SHA-384 with RSASSA-PSS

    RSA certificate with a signature algorithm of RSASSA-PSS with SHA-384 (Key sizes 2048 and larger)

    0806 – SHA-384 with RSASSA-PSS
    Any ECC secp256r1 certificate 0403 – SHA-256 with ECDSA
    Any ECC secp384r1 certificate 0503 – SHA-384 with ECDSA
    Any ECC secp521r1 certificate 0603 – SHA-512 with ECDSA
  • For TLS 1.3 handshake a CA certificate must have:
    • Critical flag set to true for Basic Constraints extension
    • must contain authorityKeyIdentifier extension
  • The support for Security Policy SP800-131a and the Suite B profile requires that the Secure Plus and System SSL be in FIPS mode. See the information below and the System SSL Programing Guide regarding FIPS.
  • Connect:Direct Secure Plus uses services from ICSF that require the Connect:Direct ID for Secure Plus and the TSO user ID of the Secure Plus Administrator to have read access defined in the RACF CSFSERV facilities class.
  • The enhancements to Connect:Direct Secure Plus such as, new protocols added, support for new security policies, and removal of support for STS require a Secure Parmfile conversion when upgrading from any release prior to 5.2. For more information see, DGASCONV – Secure Parameter File Conversion Utility.
  • IBM® Connect:Direct administrators need access to z/OS UNIX System Services in order to update SSL and TLS parameters.
  • IBM Connect:Direct needs UNIX read permission to the key database. Use the UNIX CHMOD command to change permissions, if necessary.
  • A default certificate must exist for the SSL or TLS protocol to successfully communicate with a trading partner. Use the IBM GSKKYMAN utility (or IBM RACF if using key rings) to set a trading partner certificate as the default. For information about creating and managing certificates, refer to the IBM documentation. To locate documentation, go the IBM web site and perform a search on GSKSSL10.
  • Secure connections cannot be established using LU0 or PNODE=SNODE. Nonsecure connections operate normally using these protocols.
  • You can only use the Quick Start option the first time you create and populate the Connect:Direct Secure Plus parameter file from the network map, and if your IBM Connect:Direct TCP/IP netmap entries use standard IPV4 addresses.
  • While in FIPS mode, the following are important considerations for Connect:Direct Secure Plus:
    • The certificate store must be in FIPS mode and the certificate must meet size restrictions for encryption keys. The GSKKYMAN utility can be used to create a key database for FIPS mode. In addition, other requirements of RACF might be necessary. For more information, see z/OS V1R11.0 Cryptographic Services System Sockets Layer Programming SC24-5901-08
    • While in FIPS mode, IBM Connect:Direct Secure Plus can open a FIPS mode key database; however, initialization fails if the key database is not in FIPS mode. If the FIPS initialization parameter is specified as NO, IBM Connect:Direct Secure Plus can still open and use a FIPS-mode database.
    • When Connect:Direct FTP+ is in FIPS mode, the TLS protocol is the only supported protocol. If SSL is enabled in the secure parameter file, the connection to that remote node is rejected during the TLS handshake.
    • While in FIPS mode, only certain ciphers are supported. During the TLS handshake, any non-FIPS mode ciphers are ignored. The Secure Plus Admin tool provides the following textual representation of the ciphers available in FIPS mode:
      • SSL_RSA_AES_128_SHA
      • SSL_RSA_AES_256_SHA
      • SSL_RSA_WITH_3DES_EDE_CBC_SHA
    • The following errors cause Connect:Direct FTP+ to terminate with a U4079 abend. These are critical functions and indicate a severe problem requiring immediate attention:
      CMSERR_BAD_RNG_OUTPUT
      Failure during random number generation
      GSK_ERR_RNG
      Failure during random number generation
      CMSERR_FIPS_KEY_PAIR_CONSISTENCY
      Failure when generating either an RSA or DSA keypair
      CMSERR_KATPW_FAILED
      Failure was encountered by the gsk_perform_kat API when performing known answer test against the System SSL cryptographic algorithm