Cryptanalysis of AES repeated text

Networking/Security Forums -> Cryptographic Theory and Cryptanalysis - Internal and Transmission Security

Author: robyg72Location: Milan PostPosted: Fri Oct 22, 2010 11:59 am    Post subject: Cryptanalysis of AES repeated text
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Dear all,

Iím Roberto Garavaglia, a software developer. I apologize for my bad English.

I would like to ask you a counsel about an AES encrypted text.
My application log in an encrypted text file to avoid to be read from competitors Wink
The text is like following rows:

YdGJzX77cA0skGONkzDMF6oZckHx1s0J8WONDG9PtvzFw2dzo+K/usbtOFx3YoUSFNkuJEL4GE+UY1Ep7VLPWm8cn/LJp/lSQOjswmfDJhibZ8hf3hIQbci0GDWSEPqm/Lo+XGgZT57v1GK43FPWZnv4G86woC3c0OgnFJZgZ16QNaFVlY50fGUJj0QekXDu94POqelufthAIkGpqrq9J6Mu6uZdCV6qwxxomQ0N0zA=

YdGJzX77cA0skGONkzDMF85G75aIcHmwHchz1FF++PPU4sr2Oo85ILRDijOQjDY9mM70BttB8rUj7CbpxW3FCwDHPIvYYLx7wdwQnx2kEBTO1vYBtSRj7VV/BFh2coT0K/jzks400g8FcHw+sHx85RbFskRUuvvI30hnWWPQYE9eGoAF6w17i57Qav2zk8hcWAk5bp1vg0S6CiCeVy+S5Rc49JysQmf2n7bJ6Hfg5Oo=

YdGJzX77cA0skGONkzDMFzomJ+YzVuOfhsNf2aiIu9pNm3TXrNkZGXs3+LWFe8f+BdbSQrZEW/BoFso/OY2LkCvovYJJD+wO5fnCYWKqicmNYN8faY8WOdUj5FS/xFpZXzVfecmqyqYnZXGETsSCQ8by66UzrNpwzhb5EPd39jhpsSNUfQf15Etk0Xa/eV6B1J6myM40SAbsYfmZrMn1yfblogL7R0F3h+af+XqVDp4=

As you can see in bold there is a repeated structure of text. This is the da and time...
Do you think that this can be a simplification for who want to decrypt the text?

Thank you very much and best regards!
Roberto Garavaglia

Author: rasmusbergpalm PostPosted: Fri Oct 29, 2010 1:27 pm    Post subject:
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You could use AES in 'Counter' mode http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
To ensure that your ciphertext all become different.

Cheers, Rasmus.

Author: robyg72Location: Milan PostPosted: Fri Oct 29, 2010 2:12 pm    Post subject:
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Thank you Rasmus!!!!
Very useful!

Regards, Roberto



Networking/Security Forums -> Cryptographic Theory and Cryptanalysis - Internal and Transmission Security


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