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Aug
2
awarded  Commentator
Aug
2
comment Encrypt array of int for individual retrieval
This is a very complete answer, thank you. Your reference to cryptographic terms, especially ciphertext indistinguistability, is extremely helpful.
Aug
2
accepted Encrypt array of int for individual retrieval
Jul
31
comment Why does .NET's ECB mode implementation append a constant block to my ciphertext?
You are absolutely correct. Thanks! With Padding mode set to None, I'm able to decrypt a single block. As a side note, it also now refuses to encrypt a partial block, which I don't require.
Jul
31
awarded  Scholar
Jul
31
awarded  Supporter
Jul
31
accepted Why does .NET's ECB mode implementation append a constant block to my ciphertext?
Jul
31
comment Why does .NET's ECB mode implementation append a constant block to my ciphertext?
And thanks for the DES reminder.
Jul
31
comment Why does .NET's ECB mode implementation append a constant block to my ciphertext?
You are correct, mike! Further, it was able to deduce the correct length of the final block. The last byte must be the length of the final block, so it requires an extra block to represent it.
Jul
31
comment Why does .NET's ECB mode implementation append a constant block to my ciphertext?
@mikeazo: sure, make me fix my writeBlocks function! ;) just a moment...
Jul
31
revised Why does .NET's ECB mode implementation append a constant block to my ciphertext?
added 25 characters in body
Jul
31
asked Why does .NET's ECB mode implementation append a constant block to my ciphertext?
Jul
31
revised Encrypt array of int for individual retrieval
added 4 characters in body
Jul
31
comment Encrypt array of int for individual retrieval
@fgrieu: p.s. I like your comment about it being unnecessarily complex. thanks for suggesting what would have been a better solution if I didn't mind managing session state. keep in mind, a common ASP.NET method to manage session state is to encrypt the whole session cache, send it to the client, and return it for decryption with each request. Not less complex than my current plan after all, although it is a more generic solution. :)
Jul
31
comment Encrypt array of int for individual retrieval
@fgrieu: also, I've implemented the whole application without state so far. I'm trying to keep it that way. Currently, all interactions will survive an application restart. Also, across multiple users and potentially multiple active search results, caching result list indexes (especially if they have to be persisted to the DB) will get to be a bit of a load.
Jul
31
comment Encrypt array of int for individual retrieval
@fgrieu: yeah, the URLs need to be persistent for bookmarking items and e-mailing item links. it isn't on a server farm yet, but I hope it will be someday.
Jul
31
comment Encrypt array of int for individual retrieval
2^16 on the MAC is sufficient to trigger an account abuse alarm, and I'll also implement an item retrieval quota lower than 2^16/month, to ensure that the "surjective" quality cannot be mapped by inspecting items from the result list.
Jul
31
awarded  Student
Jul
31
comment Encrypt array of int for individual retrieval
Thanks for the 3DES info, and for reviewing my design. If I don't get other answers I'll proceed with it. I suppose I could increase the block size without further-increasing the wire-size if I return pairs of IDs in addition to the already-described design.
Jul
31
awarded  Editor