Paper 2010/162

1024XKS - A High Security Software Oriented Block Cipher Revisited

Dieter Schmidt


The block cipher 1024 has a key schedule that somehow resembles that of IDEA. The user key is cyclicly shifted by a fiexed amount to form the round keys. In the key schedule of IDEA this has lead to weak keys. The primitive key schedule from 1024 may lead also to attacks with related keys. Although to the knowlegde of the author weak keys or attacks with related keys have not yet been published, there is a need to put things right. The new one-way key schedule of 1024XKS (eXtended Key Schedule) has pseudo-random round keys, which are obtained by using the cipher as randomizer.Apart from that, the user key has now to sizes, 2048 bit and 4096 bit. Also the order of the s-boxes have been changed to thwart attacks based on symmetry

Available format(s)
Secret-key cryptography
Publication info
Published elsewhere. Unknown where it was published
high security encryptionblock cipherrelated keyweak key
Contact author(s)
dieterschmidt @ usa com
2010-03-28: received
Short URL
Creative Commons Attribution


      author = {Dieter Schmidt},
      title = {1024XKS -  A High Security Software Oriented Block Cipher Revisited},
      howpublished = {Cryptology ePrint Archive, Paper 2010/162},
      year = {2010},
      note = {\url{}},
      url = {}
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