[erlang-questions] blowfish cbc mode decrypt

[Bogdan Andu]

 Data to be decrypted (arrived on socket, etc) is:
<<IvSpec:8/binary, IV:8/binary, Rest/binary>> = EncryptedData

IV is ectracted form the 8-byte prepanded value preceding
IvSpec which has the value RandomIV.

decryption of Rest should be initialized with IV.


On Thu, Nov 5, 2015 at 3:38 PM, Radoslaw Gruchalski <radek@REDACTED>
wrote:

> You say your data is:
>
> <<IvSpec>> == <<RandomIv>>
>
> But you read:
>
> Is your data <<IvSpec:8/binary, IV:8/binary, Rest/binary>>
>
> Should it not be just:
>
> <<IV:8/binary, Rest/binary>>
>
> ?
>
> Sent from Outlook <http://aka.ms/Ox5hz3>
>
> _____________________________
> From: Bogdan Andu <bog495@REDACTED>
> Sent: Thursday, November 5, 2015 2:26 p.m.
> Subject: [erlang-questions] blowfish cbc mode decrypt
> To: Erlang <erlang-questions@REDACTED>
>
>
>
> Hi,
>
> I have a stream of data called EncryptedData (with randomiv header
> specification).
> I want to decrypt  using:
> crypto:block_decrypt(blowfish_cbc, hexstr2bin(Key), IV, Rest).
>
> where:
>
> EncryptedData is formatted as follows:
> <<IvSpec:8/binary, IV:8/binary, Rest/binary>>
>
> IvSpec == <<"RandomIV">>
>
> However the decryption does not works and garbage is generated
> (the function  ) .
>
> What could be done given the fact that IV is an 8-byte quantity
> the Key is formatted according to crypto test suites and is 16 bytes long
>
> Am I missing something?
>
> Thanks,
>
> Bogdan
>
>
>
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