Enabling CipherSpecs

Enable a CipherSpec by using the SSLCIPH parameter in either the DEFINE CHANNEL or ALTER CHANNEL MQSC command.

Some of the CipherSpecs that you can use with IBM® MQ are FIPS compliant. Some of the FIPS compliant CipherSpecs are also Suite B compliant although others, such as TLS_RSA_WITH_AES_256_CBC_SHA, are not.

All Suite B compliant CipherSpecs are also FIPS compliant. All Suite B compliant CipherSpecs fall into two groups: 128 bit (for example, ECDHE_ECDSA_AES_128_GCM_SHA256) and 192 bit (for example, ECDHE_ECDSA_AES_256_GCM_SHA384),

The following diagram illustrates the relationship between these subsets:

Diagram representing the relationship between FIPS compliant CipherSpecs and Suite B compliant CipherSpecs.

[MQ 9.2.0 Jul 2020] From IBM MQ 9.2.0, the product supports the TLS 1.3 security protocol on all platforms. [z/OS] On IBM MQ for z/OS®, TLS 1.3 is supported only on z/OS 2.4 or later.

The CipherSpecs that you can use for each of these platforms are listed in Table 1. For information about using these CipherSpecs, see Using TLS 1.3 in IBM MQ and IBM MQ MQI client and TLS 1.3.

For ease of configuration and future migration, IBM MQ also provides a set of alias CipherSpecs. Migrating existing security configurations to use an alias CipherSpec means that you can adapt to cipher additions and deprecations without needing to make further invasive configuration changes in the future. These alias CipherSpecs are listed in the Alias CipherSpecs section in Table 1. For more information about migrating to use an alias CipherSpec, see Migrating existing security configurations to use an alias CipherSpec.

You can configure the default CipherSpecs as described in Default CipherSpec values enabled in IBM MQ. You can also provide an alternative set of CipherSpecs that are enabled for use with channels on:

IBM MQ for Multiplatforms, as described in Providing a custom list of ordered and enabled CipherSpecs on IBM MQ for Multiplatforms.
IBM MQ for z/OS, as described in Providing a custom list of ordered and enabled CipherSpecs on IBM MQ for z/OS.

Deprecated CipherSpecs that you can re-enable to use with IBM MQ if necessary are listed in Deprecated CipherSpecs. For information about enabling the deprecated CipherSpecs, see Enabling deprecated CipherSpecs on IBM MQ for Multiplatforms or Enabling deprecated CipherSpecs on z/OS.

CipherSpecs that you can use with IBM MQ TLS support

CipherSpecs that you can use with the IBM MQ queue manager automatically are listed in the following table. When you request a personal certificate, you specify a key size for the public and private key pair. The key size that is used during the TLS handshake is the size stored in the certificate unless it is determined by the CipherSpec, as noted in the table.

Table 1. CipherSpecs you can use with IBM MQ TLS support
Platform support¹	CipherSpec name	Hex code	Protocol used	MAC algorithm	Encryption algorithm (encryption bits)	FIPS²	Suite B
Alias CipherSpecs
All	`ANY_TLS13_OR_HIGHER` ³ ⁴ ⁵	N/A	Negotiated	Negotiated	Negotiated	Negotiated	Negotiated
All	`ANY_TLS13` ⁴ ⁵ ⁶	N/A	TLS 1.3	Negotiated	Negotiated	Negotiated	Negotiated
All	`ANY_TLS12_OR_HIGHER` ⁴ ⁵ ⁷	N/A	Negotiated	Negotiated	Negotiated	Negotiated	Negotiated
All	`ANY_TLS12` ⁸	N/A	TLS 1.2	Negotiated	Negotiated	Negotiated	Negotiated
All	`ANY` ⁹	N/A	Negotiated	Negotiated	Negotiated	Negotiated	Negotiated
CipherSpecs for TLS 1.3
All	`TLS_AES_128_GCM_SHA256`⁴	1301	TLS 1.3	GCM	AES-128 with GCM (128)	Yes	No
All	`TLS_AES_256_GCM_SHA384`⁴	1302	TLS 1.3	GCM	AES-256 with GCM (256)	Yes	No
All	`TLS_CHACHA20_POLY1305_SHA256⁴`	1303	TLS 1.3	POLY1305	CHACHA20 (256)	No	No
	`TLS_AES_128_CCM_SHA256`	1304	TLS 1.3	CBC-MAC	AES-128 with CTR (128)	Yes	No
	`TLS_AES_128_CCM_8_SHA256` ¹¹	1305	TLS 1.3	CBC-MAC	AES-128 with CTR (128)	Yes	No
CipherSpecs for TLS 1.2
All	`TLS_RSA_WITH_AES_128_CBC_SHA256`¹⁰	003C	TLS 1.2	SHA-256	AES (128)	Yes	No
All	`TLS_RSA_WITH_AES_256_CBC_SHA256` ¹⁰ ¹²	003D	TLS 1.2	SHA-256	AES (256)	Yes	No
All	`TLS_RSA_WITH_AES_128_GCM_SHA256` ¹⁰ ¹³	009C	TLS 1.2	SHA-256 and AEAD GCM	AES (128)	Yes	No
All	`TLS_RSA_WITH_AES_256_GCM_SHA384`¹⁰ ¹² ¹³	009D	TLS 1.2	SHA-384 and AEAD GCM	AES (256)	Yes	No
All	`ECDHE_ECDSA_AES_128_CBC_SHA256` ¹⁰	C023	TLS 1.2	SHA-256	AES (128)	Yes	No
All	`ECDHE_ECDSA_AES_256_CBC_SHA384` ¹⁰ ¹²	C024	TLS 1.2	SHA-384	AES (256)	Yes	No
All	`ECDHE_RSA_AES_128_CBC_SHA256` ¹⁰	C027	TLS 1.2	SHA-256	AES (128)	Yes	No
All	`ECDHE_RSA_AES_256_CBC_SHA384` ¹⁰ ¹²	C028	TLS 1.2	SHA-384	AES (256)	Yes	No
	`ECDHE_ECDSA_AES_128_GCM_SHA256` ¹² ¹³	C02B	TLS 1.2	SHA-256 and AEAD GCM	AES (SHA384)	Yes	128 bit
	`ECDHE_ECDSA_AES_256_GCM_SHA384` ¹² ¹³	C02C	TLS 1.2	SHA-384 and AEAD GCM	AES (SHA384)	Yes	192 bit
All	`ECDHE_RSA_AES_128_GCM_SHA256` ¹³	C02F	TLS 1.2	SHA-256 and AEAD GCM	AES (128)	Yes	No
All	`ECDHE_RSA_AES_256_GCM_SHA384` ¹² ¹³	C030	TLS 1.2	AEAD AES-128 GCM	AES (SHA384)	Yes	No
Notes: For a list of platforms covered by each platform icon, see Release and platform icons in the product documentation. Specifies whether the CipherSpec is FIPS-certified on a FIPS-certified platform. See Federal Information Processing Standards (FIPS) for an explanation of FIPS. The ANY_TLS13_OR_HIGHER alias CipherSpec negotiates the highest level of security that the remote end will allow but will only connect using a TLS 1.3 or higher protocol. To use TLS 1.3, or the ANY CipherSpec, on IBM MQ for z/OS, the operating system must be z/OS 2.4 or later. To use TLS 1.3, or the ANY CipherSpec, on IBM i the underlying operating system version must support TLS 1.3. See System TLS support for TLSv1.3 for more information. The ANY_TLS13 alias CipherSpec represents a subset of acceptable CipherSpecs that use the TLS 1.3 protocol, as listed in this table for each platform. The ANY_TLS12_OR_HIGHER alias CipherSpec negotiates the highest level of security that the remote end will allow but will only connect using a TLS 1.2 or higher protocol. The ANY_TLS12 CipherSpec represents a subset of acceptable CipherSpecs that use the TLS 1.2 protocol, as listed in this table for each platform. The ANY alias CipherSpec negotiates the highest level of security that the remote end will allow. These CipherSpecs are not enabled on IBM i 7.4 systems that have System Value QSSLCSLCTL set to *OPSSYS. These CipherSpecs use an 8-octet Integrity Check Value (ICV) instead of a 16-octet ICV. This CipherSpec cannot be used to secure a connection from the IBM MQ Explorer to a queue manager unless the appropriate unrestricted policy files are applied to the JRE used by the Explorer. Following a recommendation by GSKit, TLS 1.2 GCM CipherSpecs have a restriction which means that after 2ˆ24.5 TLS records are sent, using the same session key, the connection is terminated with message AMQ9288E. This GCM restriction is active, regardless of the FIPS mode being used. To prevent this error from happening, avoid using TLS 1.2 GCM Ciphers, enable secret key reset, or start your IBM MQ queue manager or client with the environment variable `GSK_ENFORCE_GCM_RESTRICTION=GSK_FALSE` set. For GSKit libraries, you must set this environment variable on both sides of the connection, and apply it to both client to queue manager connections and queue manager to queue manager connections. Note that this setting affects unmanaged .NET clients, but not Java or managed .NET clients. For more information, see AES-GCM cipher restriction. This restriction does not apply to IBM MQ for z/OS.

Using TLS 1.3 in IBM MQ

From IBM MQ 9.2.0, the product supports TLS 1.3 on all platforms. Before IBM MQ 9.2.0, TLS 1.3 support was available on AIX®, Linux®, and Windows for Continuous Delivery from IBM MQ 9.1.4.

Queue managers that are created at IBM MQ 9.2.0 or later support TLS 1.3 by default. Queue managers migrated from earlier versions of IBM MQ need to have TLS 1.3 enabled. You can enable TLS 1.3 on migrated queue managers by setting the AllowTLSV13=TRUE property:

For IBM MQ for Multiplatforms queue managers, edit the qm.ini file and add the AllowTLSV13=TRUE property under the SSL stanza (link to
```
SSL:   
  AllowTLSV13=TRUE 
```
For IBM MQ for z/OS queue managers, edit the QMINI data set specified in the queue manager startup JCL and add the AllowTLSV13=TRUE property under the TransportSecurity stanza
```
TransportSecurity: 
    AllowTLSV13=TRUE
```

When TLS 1.3 is enabled, and in accordance with the TLS 1.3 specification, any attempt to communicate with a weak CipherSpec, regardless of whether they are enabled in IBM MQ or not, is rejected. The CipherSpecs that TLS 1.3 considers weak are CipherSpecs that meet one or more of the following criteria:

Uses the SSL 3.0 protocol.
Uses RC4 or RC2 as the Encryption algorithm.
Has a encryption key size (bit) equal to or less than 112.

These restrictions are flagged with Note ^[3] in Table 1 of Deprecated CipherSpecs.

If you need to continue using such CipherSpecs, then you must disable TLS 1.3 mode:

Edit the queue manager's qm.ini file and change the setting of the AllowTLSV13 property to:
```
SSL:   
  AllowTLSV13=FALSE
```
Edit the QMINI data set of the queue manager and change the setting of the AllowTLSV13 property to:
```
TransportSecurity: 
    AllowTLSV13=FALSE
```

IBM MQ MQI client and TLS 1.3

When using the IBM MQ MQI client, the value of AllowTLSV13 is inferred unless it is explicitly specified in the SSL stanza of the mqclient.ini file that is being used by the application.

If any weak CipherSpecs are enabled, AllowTLSV13 is set to FALSE and no TLS 1.3 CipherSpecs can be used.
Otherwise, AllowTLSV13 is set to TRUE and the new TLS 1.3 CipherSpecs and alias CipherSpecs can be used.

Default CipherSpec values enabled in IBM MQ

In default configuration for a new IBM MQ queue manager, IBM MQ provides support for the TLS 1.2 and TLS 1.3 protocols and various cryptographic algorithms using CipherSpecs. For compatibility purposes, IBM MQ can also be configured to use SSL 3.0 and TLS 1.0 protocols and a number of cryptographic algorithms that are known to be weak or susceptible to security vulnerabilities. The list of CipherSpecs that are enabled in default configuration may change by applying maintenance.

It is possible to configure IBM MQ to restrict or permit the use of CipherSpecs using the following controls:

Only permit FIPS 140-2 compliant CipherSpecs using SSLFIPS.
Only permit NSA Suite B compliant CipherSpecs using SUITEB.
Permit a custom list of CipherSpecs using AllowedCipherSpecs.
Permit a custom list of CipherSpecs using the AMQ_ALLOWED_CIPHERS environment variable.
Permit the use of deprecated CipherSpecs using AllowWeakCipher or the AMQ_SSL_WEAK_CIPHER_ENABLE environment variable.
Permit the use of deprecated CipherSpecs using DD statements in the CHINIT JCL.

Note: If you specify a custom list of CipherSpecs using AllowedCipherSpecs or AMQ_ALLOWED_CIPHERS this overrides enablement of any deprecated CipherSpecs. Note that when using either NSA Suite B or FIPS 140-2 restrictions in combination with a custom CipherSpec list, you must ensure the custom list only contains CipherSpecs permitted by the Suite B or FIPS 140-2 settings.