DKIM for JavaMail is a small JAR that can be easily implemented in existing Java projects using JavaMail for sending DKIM signed emails.
This github repository replaces the original repository at http://dkim-javamail.sourceforge.net See http://sourceforge.net/p/dkim-javamail/discussion/893011/ for old forum posts.
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a project using JavaMail: http://java.sun.com/products/javamail/ (DKIM for JavaMail was tested with version JavaMail 1.4.1 but should be compatible with older versions too, see TODO below)
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a DKIM key setup:
There are test keys in the keys/ directory but be aware to use those only for your tests.
You need:
a) a private key on your hard disc (e.g. in keys/); you can generate a new key by
openssl genrsa -out private.key.pem
DKIM for JavaMail needs the private key in DER format, you can transform a PEM key with openssl:
openssl pkcs8 -topk8 -nocrypt -in private.key.pem -out private.key.der -outform der
b) a public key in your DNS; here is a sample ressource record with selector "default": default._domainkey IN TXT "v=DKIM1; g=*; k=rsa; p=MIG...the_public_key_here...AQAB" (see http://www.ietf.org/rfc/rfc4871.txt for details)
You can use openssl to get a public key from the private key:
openssl rsa -inform PEM -in private.key.pem -pubout
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if you want to run the examples provided in DKIM for JavaMail you have to
a) configure the config file test.properties (see comments inside)
b) run
ant runTests
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add DKIMforJavaMail.jar to your classpath
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see the example files in test/de/agitos/dkim/* : it's very simple to implement, enjoy!
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DKIM for JavaMail is in principal compatible with all libraries using JavaMail, an example for Apache Commons Email should be added to this project
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test of DKIM for JavaMail with older JavaMail versions, maybe a JAR for Java 1.4; I will do this if needed upon request
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verification functionality could be added; this has minor priority at time, I will do this if needed upon request (there will be other libraries doing this maybe)
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the optional public key check before sending should be fully implemented; this is out of the DKIM basic functionality and therefore isn't mandatory
1.0, 2008-11-30
1.1, 2009-04-13 Bugfix line-encoding before body canonicalization on *nix systems Added partial line-folding of the DKIM-Signature header field
1.2, 2009-05-10 Bugfix in signing mime messages that are loaded by an InputStream, Added a MimeMessageTest for testing the signing of loaded mime messages.
1.3, 2009-07-29 Changed the insertion of the DKIM-Signature header to the top most position when sending mail. This is compatible with the Yahoo! DKIM verifier.
http://www.dkim.org/deploy/ : DKIM implementations On this website you can find most MTA-DKIM implementations and complementary products and services.
http://java.sun.com/products/javamail/ : Sun JavaMail API
http://www.agitos.de/dkim-for-java-mail-open-source-library-2.html Florian Sager, sager@agitos.de, 22.11.2008