Java Security: SunJSSE and TLSAES


TLSAES defines AES ciphersuites for TLS, and from TLS version 1.1, the AES cipher suites are merged in TLS specification. The AES supports key lengths of 128, 192 and 256 bits.  However, the TLSAES specification only defines ciphersuites for 128 and 256 bits keys.
In Java security context, there is a important concept, "jurisdiction policy". The JCA framework includes an ability to enforce restrictions regarding the cryptographic algorithms and maximum cryptographic strengths available to applets/applications in different jurisdiction contexts (locations). Any such restrictions are specified in "jurisdiction policy files".

Due to import control restrictions by the governments of a few countries, the jurisdiction policy files shipped with the JDK from Sun Microsystems specify that "strong" but limited cryptography may be used. An "unlimited strength" version of these files indicating no restrictions on cryptographic strengths is available for those living in eligible countries (which is most countries). But only the "strong" version can be imported into those countries whose governments mandate restrictions. The JCA framework will enforce the restrictions specified in the installed jurisdiction policy files. 

According to the default jurisdiction policy, AES_128 is the "strong" cryptography, but AES_256 is one of "unlimited strength" cryptographies, which means that AES_256 cannot be used with the default installed JDK jurisdiction policy files.

From JDK1.4.2, the SunJSSE provider supports a number of AES_128 and AES_256 cipher suites. In 1.4.2, AES_256 cipher suites were not enabled, even if the unlimited strength JCE jurisdiction policy files were installed.  From J2SE 5.0, AES_256 cipher suites are enabled automatically if the unlimited strength JCE jurisdiction policy files are installed.

OK, then here comes the conclusion now:
  1. For JDK 1.4.2, one need to explicit set the AES cipher suites in the codes in order to get it enabled. 
  2. For AES_128 cipher suites, one can use it with the default installed JDK.
  3. TLS does not define AES_192 cipher suites.
  4. For AES_256 cipher suites, one need to use the "unlimited strength" jurisdiction policiy files.

For JDK 6, the "unlimited strength" jurisdiction policiy files could be downloaded from "Other Downloads" on http://java.sun.com/javase/downloads/index.jsp, and there is a README file inside, which describe the export/import issues, and how to install the additional policies. Please DO read the export/import lines and make sure you are allowed to use those "unlimited strength" policies.

Linkage to the blog entry at blogs.Sun.COM

Popular posts from this blog

TLS Server Name Indication Extension and Unrecognized_name

Image
Heavy Pond, Jianfengling National Forest Park, Ledong, Hainan, China It's getting hot that some TLS/HTTPS server failed with "unrecognized_name". For example, the Adobe AIR 3 Code Signing Certificate Problem , the ADT handshake alert , and the jarsigner issue with timestamp.geotrust.com , etc. This entry will discussion some background of the "unrecognized_name" alert, and the TLS Server Name Indication (SNI) extension. Background "Unrecognized_name" is an error alert, define by RFC4366 .  In section 4 of RFC4366 : - "unrecognized_name": this alert is sent by servers that receive a server_name extension request, but do not recognize the server name. This message MAY be fatal. And in section 3.1 of of RFC4366 : If the server understood the client hello extension but does not recognize the server name, it SHOULD send an "unrecognized_name" alert (which MAY be fatal). From above sections, we see that "unrecognized...
Read more

Java™ SE 7 Release Security Enhancements - Weak Cryptography Control

Weak cryptographic algorithms can now be disabled in Java SE 7 release. The MD2 Message-Digest Algorithm was disabled by default in Sun PKIX provider and SunJSSE provider. The MD2 algorithm is a cryptographic hash function developed by Ronald Rivest in 1989 , and was published in 1992 as an Informational RFC (RFC 1319) .; RFC 6149 moves RFC 1319/MD2 to historic status, "Since its publication, MD2 has been shown to not be collision-free, albeit successful collision attacks for properly implemented MD2 are not that damaging. Successful pre-image and second pre-image attacks against MD2 have been shown." Although MD2 is no longer considered secure, it remains in use in public key infrastructures as part of certificates generated with MD2 and RSA. An a countermeasure of the vulnerability, Java SE has disabled MD2 algorithm in certification path building and validation. You may wonder, Java SE has disabled MD2 algorithm in certification path building and validation in ...
Read more

JEP 115: AES-GCM CipherSuites in JDK 8

Image
Chengdu, China RFC 5288 describes the use of AES in Galois Counter Mode ( GCM ) (AES-GCM) with various key exchange mechanisms as a cipher suite for TLS. AES-GCM is an authenticated encryption with associated data (AEAD) cipher (as defined in TLS 1.2 ) providing both confidentiality and data origin authentication. Java SE had already defined the AES-GCM interfaces in Java SE 7 .  In the coming Java SE 8, as an implementation of JEP 115 , AES-GCM algorithms is implemented in SunJCE provider, and AES-GCM cipher suites are implemented in SunJSSE provider. The following SSL/TLS AEAD/GCM cipher suites, in preference order, are enabled by default in SunJSSE provider for TLS version 1.2: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (RFC 5289) TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (RFC 5289) TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (RFC 5289) TLS_RSA_WITH_AES_256_GCM_SHA384 (RFC 5288) TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384 (RFC 5289) TLS_ECDH_RSA_WITH_AES_...
Read more