Scott Timmerman is a member of the IBM Streams development team. In his presentation, Scott provides an introduction to user authentication with client certificates, discusses public key infrastructure terms and concepts, and demonstrates how to configure Streams to authenticate using client certificates.

1. © 2015 IBM Corporation
Streams Security
User Authentication with Client
Certificates
IBM Streams Version 4.1
Scott Timmerman
Streams Developement
stimmer@us.ibm.com

2. 2 © 2015 IBM Corporation
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3. 3 © 2015 IBM Corporation
Agenda
 Introduction to User Authentication with Client Certificates
 Public Key Infrastructure Terms and Concepts
 Demonstrate configuring Streams to authenticate using client certificates

4. 4 © 2015 IBM Corporation
Introduction to User Authentication with Client
Certificates
Client certificates provide another option for user authentication. InfoSphere
Streams 4.1 attempts user authentication as follows.
1.If configured, authenticates using a login module. If user can not authenticate,
continues to the next step.
2.If configured, authenticates using a client certificate. If user can not authenticate,
continues to the next step.
3.Uses default authentication method (PAM or LDAP) specified when domain was
created.
Benefits of user authentication using client certificates
 Enhanced user security
 No user password required
 User management alternative to PAM or LDAP
How does user authentication with client certificates work?
• Need to understand Public Key Infrastructure terms and concepts
• Demonstration provides a practical example.

5. 5 © 2015 IBM Corporation
Public Key Infrastructure Terms and Concepts
 Public Key Infrastructure (PKI) is a series of standards and processes used
to ensure secure electronic transfer of information. It is a system for
creation, storage and distribution of digital certificates based on public key
cryptography.
 Public Key Cryptography uses public and private keys for encrypting and
decrypting data.
– Public key is shared but the private key must be kept secret.
– Public and private keys are matched by an asymmetric mathematical
algorithm where the complexity ensures the practical impossibility of
determining the private key.
– Data is encrypted using one key and decrypted using the other.

6. 6 © 2015 IBM Corporation
Public Key Infrastructure Terms and Concepts
 Digital Certificate is an encoded file used to prove the identity of the owner.
The following are some of the contents of a X.509 v3 certificate.
– Version: Specification version of the certificate
– Serial number: Unique ID of the certificate
– Subject: Distinguished name of owning entity
– Issuer: Distinguished name of entity that issued the certificate
– Validity period: Start and end dates
– Subject Public Key Info: Public key & encryption algorithm
– X509v3 extensions:
• Basic Constraints: Identifies whether subject is a CA, etc.
• Authority Key ID: Derived from the public key of the Issuer
• Subject Key ID: Derived from the public key of the Subject
• Key Usage: Purpose of public key contained in the certificate
– X509v3 extended extensions:
• Extended Key Usage: Additional purposes of public key contain in the
certificate. (i.e. whether subject can be used for client authentication)

7. 7 © 2015 IBM Corporation
Public Key Infrastructure Terms and Concepts
 Certificate Authority (CA) is a trusted entity that has its own certificate and
does the following.
– Verifies the identity of a subject
• Anyone can create a certificate but a CA ensures the subject's identity
– Issues digital certificates
• Signs the digital certificate with the CA's private key
– Renews digital certificates
• Re-issues a certificate with new validity dates
– Revokes digital certificates
• Certificates that are no longer trusted are revoked
– Maintains a list of all certificates issued and revoked
 Certificate revocation status can be checked with the following methods.
– Certificate Revocation List (CRL)
• List of certificates revoked by a CA
• Must be created and available after a certificate has been revoked
– Online Status Protocol (OCSP)
• An OCSP response provides real time access to a certificate's revocation
status.

8. 8 © 2015 IBM Corporation
Demo
Outline
1.Obtain and verify the client and CA certificate
2.Add the CA certificate to the web management service (SWS) keystore
3.Setup Streams authorization for the certificate user
4.Setup client revocation
5.Enable client certificate authentication
6.Troubleshoot client certificate authentication problems (time permitting)
Setup and troubleshooting information for client certificate authentication is in
the InfoSphere Streams 4.1.0 Knowledge Center, see link below.
http://www.ibm.com/support/knowledgecenter/SSCRJU_4.1.0/com.ibm.streams.cfg.d
oc/doc/setting-up-certificate-authentication.html

9. 9 © 2015 IBM Corporation
Demo
1. Obtain and verify the client certificate and associated CA certificates.
a. Obtain certificates and CRL from the CA
root-ca.cert.pem Certificate of the CA that issued sub-ca certificate
sub-ca.cert.pem Certificate of the CA that issued streamsuser certificate
crl.pem Certificate revocation list generated by sub-ca
streamsuser.cert.good.pem Certificate of user issued by sub-ca (good)
streamsuser.cert.revoked.pem Certificate of user issued by sub-ca (revoked)
b. Display client and issuing CA certificate
$ openssl x509 -noout -subject -issuer -in streamsuser.cert.good.pem
subject=
/C=US/ST=MN/L=Rochester/O=Streams/OU=IBM/CN=streamsuser/emailAddress=stimmer@us.ibm.com
issuer= /C=US/ST=MN/O=Streams/OU=IBM/CN=StreamsSigner
$ openssl x509 -nout -subject -in sub-ca.cert.pem
subject= /C=US/ST=MN/O=Streams/OU=IBM/CN=StreamsSigner
c. Create a CA chain
$ cat sub-ca.cert.pem root-ca.cert.pem > ca-chain.cert.pem

10. 10 © 2015 IBM Corporation
Demo
(Step 1. continued)
d. Verify client certificate is associated with CA chain
$ openssl verify -CAfile ca-chain.cert.pem streamsuser.cert.good.pem
streamsuser.cert.good.pem: OK
$ openssl verify -CAfile ca-chain.cert.pem streamsuser.cert.revoked.pem
streamsuser.cert.revoked.pem: OK
e. Verify revocation status of client certificate
$ openssl verify -crl_check -CRLfile crl.pem -CAfile ca-chain.cert.pem streamsuser.cert.good.pem
streamsuser.cert.good.pem: OK
$ openssl verify -crl_check -CRLfile crl.pem -CAfile ca-chain.cert.pem streamsuser.cert.revoked.pem
streamsuser.cert.revoked.pem: C = US, ST = MN, L = Rochester, O = Streams, OU = IBM,
CN = streamsuser, emailAddress = stimmer@us.ibm.com
error 23 at 0 depth lookup:certificate revoked
2. Add the CA certificate that issued the client certificate to the Streams web management service (SWS)
truststore.
$ streamtool addcertificate -d stimmer-d1 --clientid StreamsSigner -f sub-ca.cert.pem
User:stimmer
Password:********
Trusted client certificate for StreamsSigner imported successfully for domain stimmer-d1.

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Demo
3. Setup Streams authorization for the certificate user.
Add certificate user to DomainAdministrator role
$ streamtool adduserdomainrole -d stimmer-d1 DomainAdministrator streamsuser
User:stimmer
Password:********
CDISC0150I The DomainAdministrator role was assigned to the following user: streamsuser. The role
applies to the stimmer-d1 domain.
4. Setup client certificate revocation checking.
The client certificate contains a URI to a CRL.
$ openssl x509 -noout -text -in streamsuser.cert.good.pem | grep -e CRL -e http
X509v3 CRL Distribution Points:
URI:http://streams107.rch.stglabs.ibm.com/certs/crl.pem
Therefore, use the default revocation settings in the Streams domain.
$ streamtool getdomainproperty -d stimmer-d1 security.revocationMethod security.revocationFile
security.revocationLdapUrl
User:stimmer
Password:********
security.revocationMethod=automatic
security.revocationFile=<undefined>
security.revocationLdapUrl=<undefined>

12. 12 © 2015 IBM Corporation
Demo
5. Enable client certificate authentication for the domain and attempt to authenticate.
Use the good certificate and notice that we are not prompted for a user so client authentication succeeded.
$ export STREAMS_X509CERT=/home/stimmer/demo/streamsuser.cert.good.pem
$ streamtool getdomainproperty -d stimmer-d1 security.revocationMethod security.revocationFile
security.revocationLdapUrl
security.revocationMethod=automatic
security.revocationFile=<undefined>
security.revocationLdapUrl=<undefined>
Use the revoked certificate and notice that we are prompted for a user so client authentication failed as
expected.
$ export STREAMS_X509CERT=/home/stimmer/demo/streamsuser.cert.revoked.pem
$ streamtool getdomainproperty -d stimmer-d1 security.revocationMethod security.revocationFile
security.revocationLdapUrl
CDISC5400E Unexpected error while performing certificate authentication. Cause: CDISA5089E An
unexpected error occurred. The error message is 'Authentication failed: The certificate with subject
(EMAILADDRESS=stimmer@us.ibm.com, CN=streamsuser, OU=IBM, O=Streams, L=Rochester, ST=MN,
C=US) has been revoked, revocation reason unknown.'.
User:stimmer
Password:********
security.revocationMethod=automatic
security.revocationFile=<undefined>
security.revocationLdapUrl=<undefined>

13. 13 © 2015 IBM Corporation
Questions?