[erlang-questions] blowfish cbc mode decrypt

[Bogdan Andu]

hi,

I really need some pointers about this issue

as i tried all kinds of combinations of IV and body
to be decrypted.

Am i missing something or there is a bug in cipher
blowfish_cbc ?



On Thu, Nov 5, 2015 at 3:51 PM, Bogdan Andu <bog495@REDACTED> wrote:

>  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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