Understanding setmqspl to set up AMS definitions.

At first glance, how difficult can it be to understand a command with only five operands? As I do not usually write about easy topics, you may be able to guess that there is some subtlety to it.

Background to AMS protection

There are three protection models in AMS. See the IBM Knowledge centre.

  1. Integrity.
  2. Encryption.
  3. Privacy = Encryption and Integrity.

Integrity

A checksum is made of the message contents, and the check sum is encrypted with the senders private key. The sender’s public key, the encrypted checksum, and the original payload are put into a message and put to a queue. This can be sent to a remote queue manager, or remain on the local queue manager. The recipient, performs the same checksum calculation on the original payload, decrypts the embedded checksum value (using information from the public certificate). If the checksums match – the messages is unchanged we have integrity

With Integrity, the getting queue manager knows the DN of the userid doing the signing.

With integrity, you need to specify which checksum technique to use, and at the getting end, you can optionally specify a list of authorised senders, and AMS will check the DN of the sender is in the list.

Confidentiality

The message contents are encrypted with a symmetric key. The key is then encrypted for the list of recipients, using the each recipient’s public key. A package of [(recipient, encrypted key) (recipient, encrypted key).. encrypted message] is put to a queue. When the message is got, the getter locates the (recipient, encrypted key) for it, uses its private certificate to decrypt the key to the data, and uses this to decrypt the message content.

With encryption you need to specify which encryption technique to use, and the list of recipients. For each recipient, AMS goes to the key store at the putting end to get the public certificate.

Privacy

A combination of Integrity and Confidentiality. The data is encrypted, and signed. The getting queue manager knows the DN of the sender.

setmqspl syntax

The syntax is

  • setmqspl
  • -m name queue manager name
  • -policy name the queue name – known as the policy name
  • -e value which cipher spec to use – or none
  • -r DN a list of 1 or more recipient’s DN
  • -s value the signing algorithm to use or none
  • -a DN a list of 0 or more acceptable signers DN values (the putter’s DN).

I’ll focus on the -e, -r, -s and -a values.

Looking at a distributed MQ environment, should make it clearer

We have a putter queue manager. Messages go to another queue manager (or stay on the same queue manager) where the messages are got.

Integrity

At the putting queue manager you need

  • setmqspl -m qmname -policy queuename -s algorithm
  • Pick an algorithm from MD5, SHA1, SHA256, SHA384, SHA512, where the SHAnnn are more secure (it is all relative) but MD5 may be faster. The algorithm you pick will be used.
  • -r and -a values are ignored from an integrity and signing perspective

At the getting end you need

  • setmqspl -m qmname -policy queuename -s algorithm <-a DN… >
  • You can specify any algorithm, (as long as the value is not NONE). This says expect a signed payload. The value is not used.
  • The -a DN1 -a DN2… the optional list of values are the authorised DNs from the certificate of the userid that put (and signed) the message. If none are specified, then no checking is done. If there is at least one specified, then the signer’s DN is checked. If it is in the list, the message is returned to the application, if it is not in the list, the message get is rolled back, or put on the SYSTEM.PROTECTION.ERROR.QUEUE queue.

Confidentiality

At the putting end you need

  • setmqspl -m qmname -policy queuename -e algorithm -r DN… .
  • Pick a digital encryption algorithm from RC2,DES,3DES,AES128,AES256 , where the AESnnn are better than the others. The algorithm you pick will be used.
  • The -r value is the DN of a potential recipient. The payload key is encrypted for each DN in the list.

At the getting end you need

  • setmqspl -m qmname -policy queuename -e algorithm .
  • You can specify any algorithm (as long as the value is not NONE), then this says expect an encrypted message. The value is not used.
  • Any -r DN values will be ignored, as they are not relevant. The recipients are identified by the presence of the encrypted key in the payload.

Privacy

See above under Integrity and Confidentially

Specifying a DN

The documentation says

  • DN attribute names must be in uppercase.
  • Commas must be used as a name separators.
  • To avoid command interpreter errors, place quotation marks around the DNs.
  • The attribute values in the DN are case sensitive so, for example, CN=USERID1 is different from CN=userid1.

There is a convention (not a standard as such) that there is a hierarchy in the terms, for example starting with CN= on the left, and C= on the right. Some key stores, such as RACF will arrange the parts of the DN into this order.

AMS allows blanks between parts, for example “CN=COLIN , O=SSS”. These padding blanks are not present in certificates, but significant blanks such as within “CN=COLIN PAICE” are kept.

When trying to resolve AMS “missing certificates” problems, I found it easier when I had the parts of the DN in the right order, and did not have extra blanks between terms. It means I could just cut and paste the DN when searching in the key store.

Brain check and reset, needed for AMS keystores on midrange.

I was working with AMS between midrange and z/OS and could not get my head around key store set up. The concept was relatively easy – it was the practice that made my head hurt.

I was reminded of a conversation with someone from MQ midrange development over the number of users that MQ should support, and whether a linked list, or binary tree would be better. The midrange guy said linked list would be OK, and easier to implement, I said a linked list would not scale. We had a break, and went for a coffee. I asked him “what do you call a large number of userids?” He replied “about 100”. “Ah, I see the problem. On z/OS 1000 is a small number of userids, and 100,000 is a large number of userids”. We then agreed the problem was too hard to solve.

I have the same sort of problem with AMS keystores. If you have 1000 client machines using MQ AMS, how do you keep the key store up to date? If someone joins the department, then the userid cannot use AMS until all of the key stores have been updated to include the userid’s public certificate.

Other applications using TLS and encryption have a key store to contain just your user’s private key information, and a trust store containing the public keys of users, or Certificate Authority (certificates you trust).
The theory being you create someone’s private key, once only, and the file with public keys can be downloaded whenever it changes, as part of the enterprise refresh of machines (think Microsoft updates which gets pushed to machines).

With AMS, there is a weakness, that only one key store is used which contains both the private, and the public keys. It is now harder to keep the key store current.

You cannot just download a key store for every one to use, as it would have all the private keys in it. (I could then use your private key, and pretend to be you.)

I had problems trying to come up with a process for updating all of the key stores, adding new certificates, and removing unwanted ones. This is where my brain had problems trying to find a solution. I gave up for the evening, and came back next morning when my brain had had a wake-up reset, and I could see a solution.

You download the public certificates file whenever there are update to it, then, on the client machine, you import the private key to this key store, rename the files ( current to old, new to current), restart the client, and then delete the old key store. This should be a simple process to implement.

If you allow a day for the change management process to approve the change to the key store, overnight download of the change, and a restart of the client at start of day, you should be able to get a change implemented in a couple of days!

Of course it is not that simple, as you have the .cms key stores used by C applications, and the Java keystores used by Java applications – so you have to worry about two keystores! But this is just a SMOP (a Small Matter Of Programming).

Overview and challenges of using end to end message encryption (AMS)

MQ provides end to end protection of messages. This covers

  • Integrity – where the message can still be read – but any changes to the message are detected. You can check the id of the person that sent it.
  • Encryption – where the payload is encrypted and only the ids with the correct private key can decrypt it.
  • Privacy – A combination of Integrity and Encryption, where only specified ids can decrypt it, and you can check the id of the person that signed it.

The messages are protected on the network, in memory and on disk. You do not need to use a channel with TLS for protection (but you may want to use TLS for authentication), as the data is protected before sending.

Any headers go as clear text, and there is additional data added to the payload containing information about the protection.

Background about encryption and signing of data

You may need to read some of the following section more than once, because it reference private keys and public keys and it is hard to work out what is happening.

The encryption techniques used are special. There is a private key and a public key. (Think of your passport as a private key, and your name and address is your public key). You can use functions

  • You do encrypt(private key, payload) to produce an encrypted payload, send it to me, and then I use decrypt(public key, encrypted payload) to recreate the original payload. I know it came from you, because I needed your public key to decrypt it.
  • I do encrypt(public key, payload) to produce an “encrypted” payload, and send it to you. Only you can use decrypt(private key, encrypted payload) with your private key to recreate the original payload.

With this

  • I can encrypt data using your public key that only someone with access to the private key (you) can decrypt
  • I encrypt with my private key, and anyone with my public key can decrypt it – and you know it came from me – because you needed my public key.

Signing is simply taking a checksum of the data, and encrypting the value with the signer’s key. When you come to check the signature, you do the same check sum calculation, decrypt the “signed” value using my public key, and the values should match. The payload would look something like “Signed by CN=Colin,O=SSS,C=GB” encrypted checksum=2294567, my certificate; followed by the original data.

We can take this further. I sign the data with my private key, and then encrypt the data(including the signed data) with your public key, (keep up at the back there – I said it was hard to follow). When you process it, only you can decrypt it because it needs your private key, and you can check the signed data, and see it came from me. I have sent the message encrypted, and have mutual authentication.

With encryption a symmetric key is used to encrypt the data, because it is faster, and about as secure as encryption with an asymmetric key. When trying to break into enciphered data, the more data you have, the easier it is to break. This is why you can reuse the symmetric key for multiple records, but you should change it, for example after 10 MB has been processed (I don’t know the best figure – it is all a matter of risk).

Sending a message, many to many.

Sending a message from one person to another person looks fairly easy. It gets a bit harder when you have potentially many people in my organisation who are allowed to send a protected message to your organisation, and there may be many people who are allowed to get, and decrypt it.

Let the people in my organisation be CN=A,O=MYORG, and CN=B, O=MYORG, and the people in your organisation be CN=X,O=YOURORG, CN=Z,O=YOURORG.

If person CN=A wants to send an encrypted message so it can be decrypted by CN=X or CN=Z the processing is as follows.

  • Do a checksum calculation on the record.
  • Encrypt this checksum using CN=A’s private certificate.
  • Put a new field of CN=A,O=MYORG|| encrypted checksum value, CN=A’s public certificate before the record.
  • Create a symmetric key.
  • Encrypt the (signed data and original payload) with the symmetric key.
  • Take the symmetric key and encrypt it for CN=X,O=YOURORG using CN=X’s public certificate. Create a field of the Distinguished Name || encrypted key.
  • Take the symmetric key and encrypt it for CN=Z,O=YOURORG using CN=Z’s public certificate. Create a field of the Distinguished Name || encrypted key.
  • Build a record of the two “encryption fields” and the encrypted data
  • Put the data in a message and send it to the recipient(s).

Getting an encrypted message

The person with CN=X gets the message.

  • Scan down the message looking for CN=X,O=YOURORG. If found then extract the encrypted symmetric key. Decrypt this value with the CN=X’s private key. This gives you the key that was used to encrypt the customer data.
  • Decrypt the message using the key you just decrypted.
  • Extract the first field and see it is signed data. We can see that the checksum was done by CN=A,O=MYORG.
  • Check this name with your list of IDs that can send you messages.
  • Validate the signer’s certificate. Either use a CA, or if the certificate was self signed, check with the copy in your trust store. Note this certificate includes the public key.
  • Take the checksum value in the message and decrypt it using CN=A,O=MYORG’s public key from the payload. Do the checksum of the remainder of the message and compare the values – they should match.

Setting up your enterprise

You need to know the list of potential recipients of messages for each queue.

At the receiving end, if you want to check the message came from an authorised id, you need to know the list of potential senders.

If you’ve managed to keep up so far – it gets worse!

The management of these lists can be difficult. If someone joins my team, I would need to tell the other organisations that they need to add CN=NEWPERSON, O=MYORG into their list of potential senders, (and remove CN=IVE_RETIRED, O=MYORG. It will take a week to get this change through their change management system. Until this is done, the message could be rejected as coming from an unauthorised person.

In the same way, you need to update the queue definitions to add CN=NEWPERSON, O=MYORG to each queue, and when people join or leave the other enterprises you’ll need to update your list of potential senders.

Do not worry too much – there is a solution, see below.

Creating the policies

With MQ, the security policy is defined using the SETMQ Security PoLicy command (setmqspl) for example to define a queue at MYORG to send message to YOURORG. The -a option is for who the message is for

setmqspl -m PRODA -p SENDQUEUE -s SHA256 -e AES128
-a "CN=X, O=YOOURORG"
-a "CN=Y, O=YOOURORG"
-a "CN=Z, O=YOOURORG"

At YOURORG for the GETQUEUE you need the following. The -r option is who you can receive a message from

setmqspl -m YOQM -p GETQUEUE 
-r "CN=A, O=MYORG"
-r "CN=B, O=MYORG"
-r "CN=JO, C=GB,O=SOMEOTHERORG"

To change an entry you have to run whole command, you cannot add one “-a” or “-r”. I would keep a file for these, update file, and process the whole file. For two queues – use two files.

You also have to consider how to update the definitions for multiple queue managers. On z/OS I would have the MQ commands inline, and use a variable queue manager name &QM, which you set in the JCL. For midrange you could have a shell script and pass the queue manager name as a parameter.

What keys do I need?

The encryption is done using RSA, and so needs a certificate with an RSA private key.

When the message is signed

Each id putting a message needs access to a private key – this could be one key shared by multiple users.

When getting a message that has been signed, the recipients will need to verify the certificate sent within the signing data; either a CA in the signing chain, or the public certificate (for self signed certificates).

When encrypting the message

The id putting the message needs access to the public key of each recipients in the list.

The id getting a message which has been encrypted, needs access to the private key.

Maintaining the public keys

For each person in the -r or -a list you will need the digital certificate, and public key in a keystore or a keyring ( on z/OS).

Each id on z/OS will need their own keyring. There is a keyring for the queue manager;s AMS address space with the public certificates on it.

On midrange MQ, each user has a keystore, with a combination of public keys, and private key(s).

Time to step back and think about what you want.

To me, it is clear that having every possible user having their own DN, and certificate quickly gets impractical. If you are working with people outside of your organisation do you want them to know the people’s names within your organisation?

You may want to have a departmental certificate for example CN=PAYROLL,O=MYORG, which members of your payroll team all use. You can control access to the queue using standard MQ security policies.

An intermediate configuration would be to have a proxy or server applications to change input messages from “partner protection” to “myorg protection”, and the reply messages changed from “myorg protection” to “partner protection”

  • You have an AMS protected input queue called EXTERNAL_IN. This has been configured to specify the DNs of the systems that can send you messages, so might specify CN=RECEIPTSPAYABLE,O=YOURORG as a valid sender.
  • If the get is successful, then put to a queue called INTERNAL_IN, specifying the DNs of the individuals in your Accounts department who are allowed to get one of the protected messages. If someone joins the Accounts department, you only need to change the configuration within your queue manager.
  • Someone (or an automated task) gets the message from INTERNAL_IN queue, it is decrypted automatically, the application does the processing and puts a message the AMS protected queue YOUR_BANK_INTERNAL, where it is encrypted by AMS.
  • Another proxy/server application in your enterprise gets the messages from YOUR_BANK_INTERNAL, checks the DN of the sender, and that they were authorised to put messages to the queue.
  • The server then puts to YOUR_BANK_EXTERNAL, using a DN of “CN=PAYROLL,O=MYORG”, and it is encrypted for the recipient.

This way you can isolate internal processing and external processing. Updating the internal list is within your control. You should not need to update the external lists (and certificates) once established.

Handling whoops’s

Some problems will result in the messages removed from the queue and put to a special error queue. You need to have a process in place to handle this. I had messages put to this queue when a userid tried to get an encrypted message, but the message had not been encrypted for this userid’s DN.

Using runamscred to encrypt the passwords in the keystore.conf file.

If you are using AMS on midrange, your keystore.conf can contain plaintext passwords to the Java private keys and keystores. This is not very secure.

You can encrypt these passwords using runamscred which takes the file, encrypts the passwords and updates the file. For example

Before

JKS.keystore = /home/colinpaice/ssl/ssl2/trust.jks
JKS.certificate = testuser
JKS.encrypted = no
JKS.keystore_pass = zpassword
JKS.key_pass = zpassword
JKS.provider = IBMJCE
amscred.keyfile=/home/colinpaice/mqamsclient/encryption.key

After

JKS.keystore = /home/colinpaice/ssl/ssl2/trust.jks
JKS.certificate = testuser
JKS.encrypted=yes
JKS.keystore_pass=<AMS>1!cu891gavGZlmnYY2DyLgbA==!W3mhqtHazVx/QDWKW/daJg==
JKS.key_pass=<AMS>1!XFS5rLL4JtlSUaAH5DdwCg==!Q6aC1547gtoqi9Q0Twlogw==
JKS.provider = IBMJCE
amscred.keyfile=/home/colinpaice/mqamsclient/encryption.key

This is documented (not very clearly) here.

The steps are

  • Create a file with a string in it. The documentation has Th1sIs@n3Ncypt|onK$y as an example.
  • Update your keystore.conf file to add a line to point to this file
    • amscred.keyfile=/home/colinpaice/mqamsclient/encryption.key .
  • This line is needed when you have Java programs.
  • Encrypt the passwords with
    • /opt/mqm/java/bin/runamscred -f keystore.conf -sp 1
  • This uses the amscred.keyfile entry to locate the encryption key. You can use -sf to specify a different file, but as the file has to have the amscred.keyfile statement. You might just as well use it, and be sure it works.!
  • The command changes JKS.encrypted to yes, and changes the passwords.

Systems management

Because the command changes the file contents, you may want to have a secure master file, master.conf, with the password in plain text in it. Make sure this file is secure (perhaps on a secure machine).

To manage the passwords

  • copy the file cp master.conf ks.conf.
  • encrypt the passwords using /opt/mqm/java/bin/runamscred -f ks.conf -sp 1.
  • send the ks.conf and the encryption key file to your end users.

pkcs11? pkcs12? .cms? .jks? .p12? .nss? which type of keystore should I use?

There are at least four types of keystore, and after an email exchange with someone, it became clear that the different types of keystore and how to use them, are not widely understood. It is one of those topics, that once you are an expert, this topic is obvious still difficult to understand. When you have little knowledge and just want to get a job done, it can be very confusing.

I’ve learned a lot from writing this post

  • There is no one tool to manage all your keys and certificate
  • You may need one keystore for your queue manager, another keystore for your C clients, another keystore for your Java clients, a keystore for a web browser and something else for curl!
  • You might need to use 3 tools to manage your keystores!

This post has sections on

This post started off as a few lines, then I though I had better explain the pre-req knowledge, and then the pre-req knowledge to the the pre-req knowlegde. I hope it provides a clear story.

What’s the difference between a trust store and a key store – when they are both called key stores?

You need a store to contain the certificates needed to check any certificates sent to the application. These are usually certificate authority certificates, but can also be self signed certificates. This store is known as a trust store – it is used to check that a certificate is trusted. None of this data is confidential, most of the information is in the public domain. One trust store could be shared by all applications, which makes the maintenance of it much easier than a trust store for each application/server.

You need a store to keep the private key used for encryption/decryption, this is known as the key store. This needs to be kept confidential. The keystore may have just one private key. You can use smart keys, or external keystores such as special USB devices.

Some products use just one store with the trust store and the private certificates combined. They also call this the keystore. If you want to isolate the keystores, you need multiple stores. This, in turn, means that if you update one trust certificate, you have multiple stores to update.

What does a store contain?

A keystore can contain

  • private information – such as you secret key which you use for encryption and decryption
  • public information, such as your Distinguished Name (CN=colin,O=SSS), and they key needed to encrypt data for me
  • trust data, if you send me a public key – can I validate it has not been tampered with?

What format is this data in?

This data is typically in one of three formats

  • Plain text
  • Binary
  • Binary portable (64 bit encoding)

Plain text

If you print a certificate or key, it comes out like

Certificate:
  Data:
    Version: 3 (0x2)
      Serial Number: 379 (0x17b)
      Signature Algorithm: ecdsa-with-SHA256
      Issuer: C=GB, O=SSS, OU=CA, CN=SSCA256
      Validity
        Not Before: Feb  9 09:35:07 2021 GMT
        Not After : Apr  9 17:40:01 2022 GMT
        Subject: C=GB, O=cpwebuser, CN=ecec
        Subject Public Key Info:
          Public Key Algorithm: id-ecPublicKey
            Public-Key: (256 bit)
            pub:
               04:5d:15:78:83:e0:ab:af:78:69:2f:14:51:fe:29:
            ...
                ASN1 OID: prime256v1
                NIST CURVE: P-256
...

Binary

The data is encoded using Abstract Syntax Notation(asn). For example you get a string of fields like

  • The following fields are a sequence
  • of length 24
  • it is a string format
  • the first item has length 8
  • the attribute type is 06 03 55 04 06 which means Country
  • the attribute value is GB
  • the second item is …

This would describe the C=GB in C=GB, O=SSS, OU=CA, CN=SSCA256.

Binary portable (base 64 encoding)

With the binary format, the data is a hex string, which is not very portable. For example if you FTP it to a remote site, you may get data conversion, and new lines changed. Often the data is converted to an intermediate form called base 64 encoding. Every 3 hex characters are converted to 4 “printable” characters A-Z,a-z,0-9 and some special characters.

The file looks like

-----BEGIN CERTIFICATE-----
MIICDjCCAbSgAwIBAgICAXswCgYIKoZIzj0EAwIwOjELMAkGA1UEBhMCR0IxDDAK
BgNVBAoMA1NTUzELMAkGA1UECwwCQ0ExEDAOBgNVBAMMB1NTQ0EyNTYwHhcNMjEw
...
hEzE3hSzUvbfLUKnua64AiEAnyKhrmBjXCVQ834VfjhNHYqjaN1PzXBE8Cv3jlWJ
9bA=
-----END CERTIFICATE-----

What are the keystore types?

When Secure Sockets Layer was being developed each major player came up with their own format for storing the certificate and key information.

  • Java had files with type .jks (java key store) for example keystore.jks
  • IBM had files with type cms (certificate management system) with file types like zzserver.crl, zzserver.kdb, zzserver.rdb, zzserver.sth. It also uses intermediate files such as .arm, which has base 64 encoding of a certifcate, as shown above.
  • Netscape had files in a NSS database, for example files in the directory /home/colinpaice/.pki/nssdb, are files cert9.db and key4.db. key4 is the keystore database (storing keys), and cert9 is the trust store database (storing certificates).
  • OpenSSL developed .p12 files which can contain certificates and keys. It also has .pem (base 64 encoded) and .der (binary) files for individual certificate, private key, and public key files .
  • Windows has .pfx files.
  • Smart cards where the keystore is on a special USB type device or other external Hardware Security Module, each have their own format keystore.

Standards were developed to work with keystores

When can different keystore types be used?

With C programs on mid range and z/OS, IBM products use GSKIT from IBM. On z/OS you can store them in the z/OS security manager (for example RACF) or on the Hardware Security Module in the processor.

Java program can use most types of keystore. You may need to configure the java.security configuration file with an entry like

  • security.provider.X=com.ibm.security.cmskeystore.CMSProvider
  • security.provider.Y=com.ibm.crypto.pkcs11impl.provider.IBMPKCS11Impl /home/colinpaice/mq/nitrokey.cfg

The first line includes support for cms files, the second includes support for a pkcs11 external keystore on an HSM (including its configuration file).

For Java programs, you configure the keystore using start-up options. The following example defines the keystore as an external USB HSM keystore, and the trust store is a openssl .p12 store.

-Djavax.net.ssl.keyStore=NONE
-Djavax.net.ssl.keyStoreType=pkcs11
-Djavax.net.ssl.keyStorePassword=12345678

-Djavax.net.ssl.trustStore=/home/colinpaice/ssl/ssl2/mytrust.p12
-Djavax.net.ssl.trustStorePassword=password
-Djavax.net.ssl.trustStoreType=pkcs12

These definitions along with the java.security, and its override, show the keystore is a pkcs11, and there is an entry in the java.security (above) pointing to the configuration file /home/colinpaice/mq/nitrokey.cfg for the pkcs11 definition. You can override or extend the options in the java.security file using configuration using

-Djava.security.properties=/home/colinpaice/mq/colin.java.properties

Do these keystores share information?

No, if you have a keystore (or a USB HSM) it shares no information with any other keystore. For example you could unplug the USB keystore, take it to another machine and plug it in, and the certificate etc will be available. You could send a .jks file, to yet another machine, and it could be used.

What can you use to administer the keystore.

IBM provided

You can use GSKCapiCmd_64 from IBM GSKIT to manage certificates and keys.

MQ has runmqakm as a command line tool which invokes GSKCapiCMD_64 under the covers.

You can also use the MQ command strmqikm to have a GUI to manage your keys and certificates. strmqikm just invokes the GSKIT ikeyman program.

These solutions feel a little dated, as I could not find if they support modern certificates capabilities; OCSP, and elliptic curves. They had a few bugs as well.

I’ve used openssl to create the “modern” private key and certificates, then imported them into the keystores using the IBM tools.

Oracle provided

With Java there is keytool. This supports a variety of keystores (depending on what has been configured in its java.security file), including

  • Java Key Stores .jks. This keystore can only be processed by java
  • Java Cryptography Extension KeyStore – a stronger version of .jks. This keystore can only be processed by java
  • pkcs12 .p12 and .pfx. These keystores can be used by Java, C and other languages, with the right API. For example Curl uses a C api to access the keystores.
  • pkcs11 – keystores on smart devices
  • nss – netscape security.

It does not support cms format keystores used by GSKIT.

Openssl

This is open source and is active, keeping up with the trends in security. Openssl deals with the building blocks; private keys, certificates etc but does not handle keystores very well. You can create manage certificates, but you may need other tools to put them into keystores.

opensc for managing smart keys and other pkcs#11 devices

(Opensc is open Smart Card.) If you have a smart key, or external keystore on an HSM, there may be hardware specific libraries for accessing the keystore, or the open source code may be supported. This can provide drivers for other tools, such as the java tools. You can also use pkcs11-tool to directly administer keys and certificates on an HSM device.

Other tools

  • pk12util from Netscape is used to mange keys in the NSS keystore databases
  • certutil from Netscape is used to manage keys and certificate in the NSS database.
  • Firefox and Chrome browsers can be used to update the NSS keystore used by the browsers.

What tool would I use when?

Creating the private key

  • When using a smart device, for example an external keystore on an USB, use the device driver or pkcs11-tool -keypairgen
  • To generate an elliptic curve, use openssl ecparam
  • To generate an RSA, use openssl genpkey
  • Use keytool keypairgen to generate an elliptic or RSA key
  • runmqakm and strmqikm(ikeyman) do not seem to support elliptic curves, but support RSA keys as part of a certificate request (see below)

Create a certificate request

The certificate request takes (or creates) the public key, creates a certificate with the DN ( eg CN=Colin,C=GB,O=SSS and creates the certificate request file.

  • openssl req takes a file from the keypairgen
  • keytool can create a certificate request, I could not see how to use the keypair gen private key as part of this
  • runmqakm and strmqikm (ikeyman) can create a request, but I do not think it supports all flavours of private key.

Sign a request

I expect most people will want a tool which you can run as a script

  • openssl ca – you can include the optional attributes, with this.
  • keytool – I could not see how to use this to sign a certificate. The documentation suggest using openssl x509.
  • runmqakm – you can use runmqakm -cert -sign .
  • strmqikm (ikeyman) I could not see how to sign a request using this, and it is a GUI.

Receive the signed certificate into the keystore

  • When using a smart device, for example an external keystore on an USB, use the device driver or pkcs11-tool –write-object
  • Use openssl pkcs12 to create a pkcs12 (.p12) keystore using the private key and signed certificate
  • Use keytool -importcert. This can support most keystore types, depending on the configuration in the java.security file.
  • runmqakm and strmqikm (ikeyman) import ( receive) the certificate and store it in the keystore.

Update the browser’s keystore

The browsers have an nss format store.

  • pk12util -i …imports a .p12 keystores into the nss “sql:” keystore. The sql: keystore is a Netscape internal format store. (you use certutil … to remove entries from the nss keystore).
  • You can use the browser’s facilities to import certificates and keys into the browsers (nss) keystore.

Receiving a public certificate into a keystore.

If you have a Certificate Authority or a self signed certificate you want to put into your trust store.

  • When using a smart device, for example an external keystore on an USB, use the device driver or pkcs11-tool –write-object
  • Openssl is not very good at adding new entries to an existing .p12 file
  • runmqakm -cert -add -file ca256.pem…
  • strmqikm, select Signer Certificates, then select Add
  • Use keytool -importkeystore.  To import a .p12 store, or a .pem file I have a shell script

ks=” -destkeystore mytrust.p12″
dest=”-deststoretype pkcs12 -deststorepass password”
src=”-srcstoretype PKCS12 -srcstorepass password”
keytool -importkeystore $ks $dest -srckeystore ca1024.p12 $src
or
keytool -import $ks $dest -file carsa1024.pem 

Which keystore should I used for which application?

All applications can use smart cards and external keystores through the standard key stores.

  • A queue manager on midrange uses cms format files, so you need to use the runmqakm or strmqikm similar files
  • A queue manager on z/OS can use the z/OS security manager (eg RACF), or the cms keystore files.
  • Firefox and Chrome browsers use the NSS format keystores.
  • Java clients can use a variety of keystores, .jks, .p12, smart cards
  • A C, .Net etc client use cms format keystores
  • Curl can use .pem files (from openssl) and .p12 files
  • A web server has trust stores, and keystores. You configure the supported formats in the java.security file. It can use jks, .p12 and smart cards.

Summary

It all looks a bit of a mess, and you need to know a lot to get your job done.

Debugging external smart cards and external pkcs11 keystores.

There is an open source package (opensc) which provides access to smart cards and external keystores. It provides some good tools for diagnosing problems.

There is a wiki with good information.

Opensc return codes are here, and the printable text is here

Monitor traffic to and from the device.

You can monitor the traffic to and from the device by using an intermediate “spy” module which displays the traffic.

In your configuration (for example a CCDT), where you specified the name of the module /usr/lib64/pkcs11/opensc-pkcs11.so, replace this with /usr/lib64/pkcs11/pkcs11-spy.so. Specify the environment variable

export PKCS11SPY=/usr/lib/x86_64-linux-gnu/pkcs11/opensc-pkcs11.so

The spy module is invoked, prints out the parameters, and then invokes the module specified in the environment variable.

The output is like

19: C_Login
2021-03-10 14:22:47.947
[in] hSession = 0x21fc030
[in] userType = CKU_USER
[in] pPin[ulPinLen] 00000000021fb2a0 / 8
00000000 5B C7 E7 BB E5 FC 6A BE […..j.
Returned: 160 CKR_PIN_INCORRECT

Detailed internal trace

You can specify the environment variable OPENSC_DEBUG to give a very detailed trace. The higher the number the more detailed the trac.

export OPENSC_DEBUG=9

and use unset OPENSC_DEBUG to reset it.

You can use OPENSC_CONF to specify a configuration file with more parameters, such as file name for the output.

The output from this trace (showing a logon with pin number 12345678) is like

0x7f96e2dca740 14:13:16.756 [opensc-pkcs11] framework-pkcs15.c:1494:pkcs15_login: pkcs15-login: userType 0x1, PIN length 8
0x7f96e2dca740 14:13:16.756 [opensc-pkcs11] pkcs15-pin.c:301:sc_pkcs15_verify_pin: called
….
0x7f96e2dca740 14:13:16.757 [opensc-pkcs11] reader-pcsc.c:283:pcsc_transmit: reader ‘Nitrokey Nitrokey HSM (DENK01051600000 ) 00 00’
0x7f96e2dca740 14:13:16.757 [opensc-pkcs11] reader-pcsc.c:284:pcsc_transmit:
Outgoing APDU (13 bytes):
00 20 00 81 08 31 32 33 34 35 36 37 38 . …12345678

GSKIT return codes

If you are using the MQ C Client interface, this uses GSKIT. There is documentation for the z/OS version, and the return codes are here.

Getting a Java program to use a TLS MQ channel, and use an external USB keystore.

This project started off trying to get a java program to use an HSM (external keystore on a USB). This was not well documented, so I have documented my path.

I had set up my keystore on the USB HSM device as described here. This post covers the MQ side of it.

MQ provides some JMS samples.

I could use JmsBrowser using local bindings with the jms.sh script.

. /opt/mqm/java/bin/setjmsenv64
java -Djava.library.path=/opt/mqm/java/lib64 JmsBrowser -m QMA -d CP0000

To use a client channel (QMACLIENT) was easy, the program is configured to allow a channel name to be passed as a parameter using the -l option.

. /opt/mqm/java/bin/setjmsenv64
java -Djava.library.path=/opt/mqm/java/lib64 JmsBrowser -m QMA -d CP0000 -h localhost -p 1414 -l QMACLIENT

To use a TLS channel (QMAQCLIENTTLS) proved harder

. /opt/mqm/java/bin/setjmsenv64
java -Djava.library.path=/opt/mqm/java/lib64 JmsBrowser -m QMA -d CP0000 -h localhost -p 1414 -l QMAQCLIENTTLS

This gave me

CC=2;RC=2397;AMQ9641: Remote CipherSpec error for channel ‘QMAQCLIENTTLS’ to host ”. [3=QMAQCLIENTTLS]

It was hard to find where to specify the CipherSpec. The documentation said “Using the environment variables MQCHLLIB to specify the directory where the table is located, and MQCHLTAB to specify the file name of the table.” I tried this and got the same error.

I collected a trace using the Java option -Dcom.ibm.msg.client.commonservices.trace.status=ON , but the trace showed the cipher spec was null.

I gave up with this program and used an enhanced version of the program. JMS programs can use JNDI as a file repository of configuration information and the program can extract the information. For example you can configure Connection Factories(cf) which are MQ connections, and Q objects – which are queues.

Use JNDI to store parameters

JMS programs can use a JNDI interface to access configuration parameters stored in an external file.
I used this article to get me started.

My JMSAdmin.config had

INITIAL_CONTEXT_FACTORY=com.sun.jndi.fscontext.RefFSContextFactory
PROVIDER_URL=file:///home/colinpaice/mq/JNDI-Directory
SECURITY_AUTHENTICATION=none

I used the following commands to define a connection factory called CF1, using the channel, QMACLIENT, and a queue reference called MYQUEUE pointing to queue CP0000.

mkdir JNDI-Directory
/opt/mqm/java/bin/JMSAdmin -v -cfg JMSAdmin.config
define cf(CF1) transport(client) channel(QMACLIENT)
define q(MYQUEUE) queue(CP0000)
end

I used a bash script to run the program, using the JmsJndiBrowser sample (JmsBrowser with JNDI support).

. /opt/mqm/java/bin/setjmsenv64
java -Djava.library.path=/opt/mqm/java/lib64 JmsJndiBrowser -i file:///home/colinpaice/mq/JNDI-Directory -c CF1 -d MYQUEUE

This failed with

JMSCMQ0001: IBM MQ call failed with compcode ‘2’ (‘MQCC_FAILED’) reason ‘2400’ (‘MQRC_UNSUPPORTED_CIPHER_SUITE’).

Which was a surprise to me. I looked in the trace, and there was nothing obviously wrong. The channel was not configured for TLS.

I used the following command in the JMS Admin tool, to specify a TLS channel and configure the cipher suite

alter cf(CF1) channel(QMAQCLIENTTLS) SSLCIPHERSUITE(ANY_TLS12)

Note. If I displayed cf(CF1) it gave me SSLCIPHERSUITE(*TLS12).

This gave me unable to find valid certification path to requested target, which was good progress because it meant the cipher spec had been accepted.

I added in the Java parameters to identify the key store and trust store

. /opt/mqm/java/bin/setjmsenv64

kss=”-Djavax.net.ssl.keyStore=/home/colinpaice/ssl/ssl2/ecec.p12″
ksp=”-Djavax.net.ssl.keyStorePassword=password”
kst=”-Djavax.net.ssl.keyStoreType=pkcs12″
tss=”-Djavax.net.ssl.trustStore=/home/colinpaice/ssl/ssl2/dantrust.p12″
tsp=”-Djavax.net.ssl.trustStorePassword=password”
tst=”-Djavax.net.ssl.trustStoreType=pkcs12″
ks=”$kss $ksp $kst”
ts=”$tss $tsp $tst”

java $ks $ts -Djava.library.path=/opt/mqm/java/lib64 JmsJndiBrowser -i file:///home/colinpaice/mq/JNDI-Directory -c CF1 -d MYQUEUE

and it worked successfully.

Use the pkcs11 HSM external keystore.

I changed the file to specify the external keystore (with format pkcs11) on a USB device rather than a file on disk (format pkcs12).

kss=”-Djavax.net.ssl.keyStore=NONE”
kst=”-Djavax.net.ssl.keyStoreType=pkcs11″
ksp=”-Djavax.net.ssl.keyStorePassword=12345678″

but this gave

find /java.security.KeyStoreException: pkcs11 not found
java.security.NoSuchAlgorithmException: pkcs11 KeyStore not available

You have to tell Java where to find the pkcs11 code. This is configured in the java.security file. You can find it using find $JAVA_HOME/ -name java.security . This gave me the file name /usr/lib/jvm/java-8-oracle/jre/lib/security/java.security

It had the list of security providers,

security.provider.1=sun.security.provider.Sun
security.provider.2=sun.security.rsa.SunRsaSign
security.provider.3=sun.security.ec.SunEC
security.provider.4=com.sun.net.ssl.internal.ssl.Provider
security.provider.5=com.sun.crypto.provider.SunJCE
security.provider.6=sun.security.jgss.SunProvider
security.provider.7=com.sun.security.sasl.Provider
security.provider.8=org.jcp.xml.dsig.internal.dom.XMLDSigRI
security.provider.9=sun.security.smartcardio.SunPCSC

and is missing an entry for pkcs11.

You can edit this file, or override it. To override it, create a file like colin.java.properties with

security.provider.10=SunPKCS11 /home/colinpaice/mq/nitrokey.cfg

where

  • .10 is the next in sequence after the .9 in the java.security file
  • SunPKCS11 says use the Sun module.
  • /home/colinpaice/mq/nitrokey.cfg use this configuration file for the pkcs11 device.

Tell Java to use this override file, by using the Java option -Djava.security.properties=/home/colinpaice/mq/colin.java.properties.

The configuration file name for the pkcs11 is /home/colinpaice/mq/nitrokey.cfg with content

name = nitrokey
library = /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so
slot=0

With these parameters the output from the JmsJndiBrowser command was

Initial context found!
Browse starts
No more messages
SUCCESS

Success – and it only took me half a day! The hardest part was known what to specify for the security.provider…… parameter.

Using the runmqakm commands and an HSM (but not strmqikm).

I tried to use strmqikm but it gave an exception.

You can use some of the runmqakm commands you know and love, to access a certificate with an HSM. For example

The command to list the database available to the runmqakm command,

runmqakm -keydb -list -crypto /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so

Gives

/usr/lib/x86_64-linux-gnu/opensc-pkcs11.so : UserPIN (mytoken)

You can then use the token label UserPIN (mytoken) and password to use the key store, for example

runmqakm -cert -list all -crypto /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so
-tokenlabel “UserPIN (mytoken)” -pw 12345678

gives

Certificates found
* default, - personal, ! trusted, # secret key
-	my_key3

and

runmqakm -cert -details -crypto /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so
-tokenlabel “UserPIN (mytoken)” -pw 12345678
-label my_key3

displays the details of the certificate with label my_key3.

If the -tokenlabel was wrong or the -pw was wrong, I got the unhelpful messages

  • CTGSK3026W The key file “pkcs11” does not exist or cannot be read.
  • CTGSK2137W The label does not exist on the PKCS#11 device.

Create your certificate request

The following command create a new RSA private-public key pair and a PKCS10 certificate request. The documentation for runmqakm says it supports RSA. If you want to use an Elliptic Curve you will need to use an alternative method, for example openssl.

runmqakm -certreq -create -crypto /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so
-tokenlabel “UserPIN (mytoken)” -pw 12345678
-dn “cn=colin,o=SSS” -file runmq.csr -label runmqlab -size 1024

Sign it

openssl ca -config openssl-ca-user.cnf -policy signing_policy -md sha256 -cert carsa1024.pem -keyfile carsa1024.key.pem -out runmq.pem -in runmq.csr

Store it back into the HSM keystore

I could not get the runmqakm command to receive the signed certificate and store it into the HSM keystore.

runmqakm -cert -receive -crypto /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so -tokenlabel “UserPIN (mytoken)” -file runmq.pem -pw 12345678

It failed with

CTGSK3034W The certificate request created for the certificate is not in the key database.

I could use

openssl x509 -inform pem -outform der -in runmq.pem -out runmq.der
pkcs11-tool –write-object runmq.der –type cert –label “runmqlab” -l –pin 12345678

The openssl command converts the file from .pem format, to .der format as .der format is required by pkcs11-tool.

Using strmqikm – the theory

If you want to use the strmqikm GUI, you have to configure the java.security file. For example edit /opt/mqm/java/jre64/jre/lib/security/java.security and add the next security.provider in the list.

security.provider.12=com.ibm.crypto.pkcs11impl.provider.IBMPKCS11Impl /home/colinpaice/mq/nitrokey.cfg

Where /home/colinpaice/mq/nitrokey.cfg is the configuration file, with

name = nitrokey
library = /usr/lib/x86_64-linux-gnu/opensc-pkcs11.so
slot=0

You can then use Ctrl+O, which brings up a pop up with “Key database type”. In this list should be PKCS11Config, if not check your java.security file. Select this, leave File Name and Location empty, and click “OK”. It pops up “Open Cryptographic Token” with the “Token Label” value taken from the configuration file name = nitrokey. This is strange as the runmqakm command uses a TokenLabel of “UserPIN (mytoken)”.

In practice…

I then got an exception java.lang.RuntimeException: PKCS11KeyStore.java: findSigner(): Failure while executing cobj.getX509Certificate(certFactory, session), and strmqikm ended.

Using a hardware security module USB as a keystore for a browser.

Background to certificates and keystores

When using TLS(SSL) you have two keystores

  • A keystore for holding the public part and private key of your certificate
  • A trust store which holds the public keys of certificate sent to you which you need to authenticate.

Your certificate has two parts

  • The private key which contains information needed to encrypt information you send. This needs to be kept private.
  • The public part,which has information that is needed to decrypt information you have encrypted, along with information such as your Distinguished Dame (DN) such as CN=ColinPaice C=GB,O=StromnessSoftware

The process of creating a signed certificate is

  • Create a private key and public key. This can be done using an external device Hardware Security Module (HSM), such as the Nitrogen HSM USB, or software, for example using OPENSSL. This produces a private key file, and a certificate request file containing the public information.
  • Send the public information to your certificate authority which signs it, and returns it
  • Import the signed public certificate into your keystore.

Creating a certificate using an HSM as the key repository

I used openssl to process my certificates, I’ve discussed the openssl setup here.

I use a bash script because it is easy to parametrize, and makes it easy to rerun until it works. I’ll give the script, then explain what it does

  • enddate=”-enddate 20240130164600Z”
  • name=”hw”
  • rm $name.key.pem
  • rm $name.csr
  • rm $name.pem
  • ca=”carsa1024″
  • pkcs11-tool –keypairgen –key-type rsa:2048 –login –pin 648219 –label “my_key3”
  • OPENSSL_CONF=eccert.config openssl req -new -engine pkcs11 -keyform engine -key label_my_key3 -out $name.csr -sha256 -subj “/C=GB/O=HW/CN=colinpaice” -nodes
  • openssl ca -config openssl-ca-user.cnf -policy signing_policy -md sha256 -cert $ca.pem -keyfile $ca.key.pem -out $name.pem -in $name.csr $enddate
  • openssl x509 -inform pem -outform der -in $name.pem -out $name.der
  • pkcs11-tool –write-object $name.der –type cert –label “my_key3” -l –pin 648219

What does the script do ?

enddate=”-enddate 20240130164600Z”

This sets the end date for the certificate – the end date is set when it is signed.

name=”hw”

This is used within the script to ensure the correct files are being used.

Remove old intermediate files
  • rm $name.key.pem
  • rm $name.csr
  • rm $name.pem
ca=”carsa1024″

Define the name of the CA files to use at signing time. The $ca.pem and $ca.key.pem are both needed.

pkcs11-tool –keypairgen –key-type rsa:2048 –login –pin 648219 –label “my_key3”
  • pkcs11-tool use this tool
  • –keypairgen to create a key pair (private and public pair)
  • –key-type rsa:2048 use this key type and key length
  • –login –pin 648219 login with the pin number
  • –label “my_key3” use this label to identify the key
OPENSSL_CONF=eccert.config openssl req -new -engine pkcs11 -keyform engine -key label_my_key3 -out $name.csr -sha256 -subj “/C=GB/O=HW/CN=colinpaice”
  • OPENSSL_CONF=eccert.config this sets up the openssl config file. Having -config eccert.config does not work. See here.
  • openssl
  • req this is to create a certificate requests – create a .csr.
  • -new it is a new request
  • -engine pkcs11 use the named engine, pkcs11, defined to the system
  • -keyform engine this says use the engine (HSM). Other choices are der and pem
  • -key label_my_key3 go to the engine and look for the my_key3 label
  • -out $name.csr create this request file with this name.
  • -sha256 using this signature
  • -subj “/C=GB/O=HW/CN=colinpaice” the name to go in the certificate. It uses colinpaice as the certificate will be used to authenticate with the mq web server, and this is the userid the mq web server should use.

Send the .csr file to the CA for signing (which is the same machine in my case).

openssl ca -config openssl-ca-user.cnf -policy signing_policy -md sha256 -cert $ca.pem -keyfile $ca.key.pem -out $name.pem -in $name.csr $enddate
  • openssl ca Use this command to sign the certificate
  • -config openssl-ca-user.cnf use this configuration file
  • -policy signing_policy use this policy within the config file
  • -md sha256 use this for the message digest
  • -cert $ca.pem use the public certificate of the CA
  • -keyfile $ca.key.pem use this private key of the CA to encrypt information about the csr request’s certificate
  • -out $name.pem whee to store the output
  • -in $name.csr the input .csr request
  • $enddate specify the certificate expiry date – set at the top of the script

Send the signed certificate back to the requester.b

openssl x509 -inform pem -outform der -in $name.pem -out $name.der

The pkcs11-tool uses .der files so convert the .pem file to .der format

  • openssl x509
  • -inform pem input format
  • -outform der output format
  • -in $name.pem hw.pem
  • -out $name.der hw.der
pkcs11-tool –write-object $name.der –type cert –label “my_key3” -l –pin 648219

Read the signed certificate and write it to the HSM

  • pkcs11-tool
  • –write-object $name.der write onto the HSM the file hw.der coverted above
  • –type cert import type (cert|pubkey|privkey)
  • –label “my_key3” use this name
  • -l –pin 648219 and logon with this pin number

Define the HSM to Chrome browser

Stop the browser because you need to update the keystore.
The command was issued in the home directory, because key store is in the home directory/.pki .

modutil -dbdir sql:.pki/nssdb/ -add “my_HSM” -libfile opensc-pkcs11.so

  • modutil use this command
  • -dbdir sql:.pki/nssdb/ to up date this keystore (in ~)
  • -add “my_HSM” give it this name
  • -libfile opensc-pkcs11.so and use this file to communicate to it

Display the contents of the browser’s keystore

modutil -dbdir sql:.pki/nssdb/ -list

This gave me

Listing of PKCS #11 Modules
 NSS Internal PKCS #11 Module
...
 Mozilla Root Certs
 library name: /usr/lib/x86_64-linux-gnu/nss/libnssckbi.so
...
my_HSM
 library name: opensc-pkcs11.so
    uri: pkcs11:library-manufacturer=OpenSC%20Project;library-description=OpenSC%20smartcard%20framework;library-version=0.17
  slots: 1 slot attached
 status: loaded
 slot: Nitrokey Nitrokey HSM (DENK01051600000         ) 00 00
 token: UserPIN (SmartCard-HSM)
   uri: pkcs11:token=UserPIN%20(SmartCard-HSM);manufacturer=www.CardContact.de;serial=DENK0105160;model=PKCS%2315%20emulated 

Restart the browser.

Use an URL which needs a certificate for authentication.

The browser prompts for the pin number (twice), and displays the list of valid certificate CNs. Pick one. When I connected to the mqweb server, I had 3 certificates displayed. I had to remember which one I wanted from the Issuer’s CN and serial number. For example

SubjectIssuerSerial
colinpaiceSSCARSA1024019c
ibmsys1SSCARSA1024019a
170594SSCARSA10240197
Select a certificate

(Having a CA just for HSM keys, such as SSSCAHSM would make it more obvious.)

Setting up digital certificates for identification in your enterprise.

You can use digital certificate for authentication, for example you can logon onto the MQ Web server using a certificate to identify you, and you do not have to enter a userid or password.

Many systems have Multi Factor Authentication (MFA) to logon which usually means you authenticate with something you have, and with something you know. Something you have is the private certificate, something you know is userid and password.

At the bottom I discuss having an external device for your keystore to make your keystore more secure.

General background and information

  • Your certificate has a private key (which should not leave your machine), and a public part, which anyone can have.
  • You can have a key store which has your private key in it. This is often just a file which could be copied to another machine. This is not a very secure way of keeping your certificates, as there is usually a stash file with the password in it, which could easily be copied along with the keystore.
  • You have a trust store which contains the public part of the certificates you want to validate (demonstrate trust) with. This is usually a set of Certificate Authority public keys, and any self signed certificates. The information in these certificates is commonly available and can be world read. You will want to protect this for write, so people cannot insert CAs from the bad guys.
  • You can use Hardware Security Module, a piece of hardware which can store your private keys, and does encryption for you. This is a secure way of keeping your certificates. You need physical access to the machine to be able to physically access the HSM hardware.
  • Certificates are based on trust. When I create a public certificate, I can get this signed by a Certificate Authority. When I send my public certificate to you, and you have the same Certificate Authority, you can check what I sent you using the Certificate Authority. My public certificate give information on how to decrypt stuff I send you.
  • When a connection is made between a client and a server. The server sends down its certificate for the client to validate and accept, and the client can then send up a certificate for the server to validate and accept. This is known as the handshake
  • A certificate has a Distinguished Name. This is like “CN=COLIN,OU=TEST,O=SSS.ORG” so my Common Name is COLIN, The Organizational Unit is TEST, and my Organization is SSS.ORG.
    • Some products like the mid-range MQ Web Server map the CN to a userid.
    • As part of the logon a client or server can check the certificate sent to it, for example allow any certificate with OU=TEST, and O=SSS.ORG.

Planning for TLS and certificate

Consider a simple scenario of two MQ Servers, and people from my.org and your.org want to work with MQ. Leaving aside the task of creating the certificate, you need to decide

  • What name hierarchy you want, for example CN=”COLIN PAICE”, OU=TEST, C=GB, O=SSS.ORG,
    • do you want to have a CN with a name in it, or a userid, or a personnel number. This is used by the MQWeb as a userid. You could have CN=MQPROD1, etc to give each server its own CN.
    • Do you want to have the country code in it C=GB? What happens if someone moves country. You might decide to have servers with CN=MQPROD1,OU=PROD… or OU=TEST… .
  • What CA hierarchy do you want. You could have a CA for OU=PROD, O=SSS.ORG at the PROD level, or CN=CA,O=SSS.ORG at the organisation level. Some servers can check the issuer is OU=PROD, O=SSS.ORG and so only allow certificates signed by that CA. Someone connecting with a certificate signed with OU=TEST,O=SSS.ORG would not be allowed access.
  • You could give each server the same DN, for example CN=MQSERVER,OU=PROD,O=SSS.ORG, or individual ones CN=MQSERVER1,OU=PROD,O=SSS.ORG
  • You can have a server check that a certificate is still valid by using Online Certificate Status Protocol (OCSP). After the handshake, a request goes to a remote server asking if the certificate is still valid. Ive written a blog post Are my digital certificates still valid and are they slowing down my channel start? z/OS does not support OCSP. MQ on z/OS supports a LDAP repository of Certificate Revocation Lists. If you intend to use OCSP you need to set up the OCSP infrastructure.
  • With the MQ mover, you can set up CHLAUTH records to allow or disallow DN’s or CA certificates.
  • The clients from my.org have a DN like CN=COLIN,OU=TEST,O=myorg.com. The clients from your.org have a DN like CN=170594,c=GB,o=your.org. You cannot have one string (SSLPEER) to allow both format certificates.
    • For connections to the chinit(mover) you can use CHLAUTH to give find grained control.
    • For the MQWeb on z/OS you can control which certificates (or Issuers) map to a userid.
    • For mid-range MQWEB you have no control beyond a successful handshake. CN=COLIN,o=MY.ORG, and CN=COLIN,o=YOUR.ORG would both map to userid COLIN even though they are from different organisations. The CN is used as a userid, and you map userids or groups to security profiles.

Setting up your certificates

As your private key should not leave your machine, the standard way of generating a certificate is

  • The client machine creates a certificate request. This has the public certificate, and the private key.
  • The public certificate is sent to the appropriate authority (a department in your organization) which signs the certificate. Signing the certificate consists of doing a check sum of the public certificate, encrypting the check sum value, and packaging the public certificate, the encrypted checksum, and the CA public certificate into one file. This file is sent back to the requester
  • The originator reads the package stores it in a keystore, and uses this as its public key.
  • Often this request for a certificate is allowed only when the machine is connected locally to the network, rather than over the internet. This means people need to bring their portable machines into the office to renew a certificate.

If you create the private certificate centrally and email it to the end user, someone who is snooping on the email will get a copy of it!

A machine can have more than one keystore and a keystore can have one or more certificates. With some servers you can configure the default certificate to use. If not they the “best” certificate is chosen. This could depend on the strength and selection of the cipher specs.

What if’s

Once you have set up your certificate strategy it is difficult to change it, so it is worth setting up a prototype to make sure the end to end solutions work, then throwing the prototype away and starting again.

You need to consider how to solve problems like

  • What if someone leaves my organisation, how do I inactivate the certificate
  • What happens of someone loses their laptop, how do I inactivate the certificate
  • Certificates have expiry dates. What do I need to do to renew the certificate before it expires – for example you could email the owner and tell them to bring the laptop to the office to renew the certificate
  • What happens if a CA expires?
  • Someone joins the department how do I update the access lists. Usually this is done using a repository like LDAP.
  • Are the CHLAUTH records restrictive enough to prevent the wrong people from getting access, but broad enough that you do not need to change them when someone joins the organisation.
  • What if you open up your business to a new organisation with a different standard of DN? What do you need to change to support it.

Use of physical keystores.

You can have a physical keystore to store your private key. This can range from a USB device up to integrated devices.
With these people cannot just copy the keystore and stash file, they need physical access to the device.

You need to plan how these will be used in your organisation for example you have two machines for HA reasons. Each has a USB store. Does each machine need its own private key? How do you handle disaster recovery when someone loses/breaks the keystore.

Physical keystores can have have a secure export and import capability. You configure a key onto the device, for example saying it needs 3 partial keys, needing three people to enter their portion of it. When you export the key, it comes out encrypted.

In this scenario the configuration process could be

  • Configure the first device. 3 people enter their password.
  • Create a private key
  • Export the private key and send it to the second machine. It is encrypted so can safely be sent.
  • Go to the second machine, and configure the second device.
  • As before, the three people have to configure the device.
  • Import the encrypted certificate to the device
  • Go the the next machine etc.
  • In some cases you can say that n out of m people are required to configure the device. So any 3 out of a team of 6 is enough.