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Java Forum / Security / March 2005Java encryption <--> .NET encryption
Hajo, I need to exchange encypted data between .NET and Java environments. The first problem I encountered is that symmetric ciphers in .NET needs initialization vector and Java counterparts don't. Can some one point me out the place where I can find any practise and patterns for encrypted communication between Java and .NET ? thanks for any info Gawel A bit of discussion and some sample code for this for 3DES case: http://www.jensign.com/JavaScience/dotnet/NetDESEncrypt - Mitch Gallant > Hajo, > I need to exchange encypted data between [quoted text clipped - 11 lines] > > Gawel > A bit of discussion and some sample code for this for 3DES case: > http://www.jensign.com/JavaScience/dotnet/NetDESEncrypt At first glance looks great. Thanks for it. Did you do similar comparison with RSA ? Gawel http://www.jensign.com/JavaScience/dotnet/RSAEncrypt - Mitch > > A bit of discussion and some sample code for this for 3DES case: > > http://www.jensign.com/JavaScience/dotnet/NetDESEncrypt [quoted text clipped - 3 lines] > > Gawel > http://www.jensign.com/JavaScience/dotnet/RSAEncrypt Hajo, have you ever exchange RSA public key using Base64 between Java and .NET? I have no problem with exchanging of symmertic key(AES, DES) but for RSA I got modulus can not be negative exception. I think it is connected with bytes order but I do not know what is going on. regards Gawel >> http://www.jensign.com/JavaScience/dotnet/RSAEncrypt > [quoted text clipped - 5 lines] > not be negative exception. I think it is connected with bytes > order but I do not know what is going on. I found the reason of problem. I have 1024 bit RSA. Modulus in java has 129 bits and privateExponnet has 129 bits but in .NET modulus has 128 bits and private exponent has 128 bits. Java adds leading 0 to modulus and privateExponent. When you add this 0 all is ok. Can you explain it ? regards Gawel Shouldn't be a problem .. after all Modulus is simply a number and same with exponent. That extra 0 is a leading 0 in Big Endian number so has no significance. If you are careless with interpreting your bits in swapping from little to big Endian .. it could cause a problem. I think that "artifact" is documented in some of my C# source code :-) - Mitch > >> http://www.jensign.com/JavaScience/dotnet/RSAEncrypt > > [quoted text clipped - 16 lines] > > Gawel Hajo, > Shouldn't be a problem .. after all Modulus is simply a number and > same with exponent. That extra 0 is a leading 0 in Big Endian number > so has no significance. if you encode base64 key then it has :) >If you are careless with interpreting your bits > in swapping from little to big Endian .. it could cause a problem. > I think that "artifact" is documented in some of my C# source code :-) Exactlly but in context of .NET and CryptoAPI. Gawel wrote: >>>>http://www.jensign.com/JavaScience/dotnet/RSAEncrypt >>> [quoted text clipped - 16 lines] >> >>Gawel One more thing. In this article you mentioned that RSA is not in JCE. But here I see RSA: http://java.sun.com/j2se/1.4.2/docs/guide/security/jce/JCERefGuide.html#AppA Can you explain me whre is the truth :) Gawel Pre JSE 1.5 RSA was only available for digital signature (not for encryption/enveloping). However, provider was updated in JSE 1.5 to include RSA encryption capability: http://java.sun.com/j2se/1.5.0/docs/guide/security/enhancements15.html - Mitch Gallant > One more thing. > In this article you mentioned that RSA [quoted text clipped - 4 lines] > > Gawel > A bit of discussion and some sample code for this for 3DES case: > http://www.jensign.com/JavaScience/dotnet/NetDESEncrypt I implemented AES using your pattern and all works great except 256 bit keys. In this case I got exception about not supported key length and in documentation is written that JCE implementation of AES suppoerts 128, 192 and 256 bit keys. One more thing, you can add to your article that decrypted .NET bytes needs to be converted into String in Java using following statement: string plainDotNetText = new String(decryptedBytes, "UTF-16LE"); thanks once again for help Gawel Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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