Problems implementing Rijndael

[Ignacio De Marco]

I'm not very familiar with C, so I would like to ask you how can use
the algorithm Rijndael, suppousing that I want two simple functions (in C ANSI)
implementing the CBC or ECB Modes (is the same for me, because I have
both implementations in Delphi, but i need the same implementations in
C for an AS400) with an interface similiar to this (in Object Pascal):

function Encrypt(PlainTe xt: string; Key: string): string

function Decrypt(Encrypt edText: string; Key: string): string


Thanks in regard,

Ignacio De Marco.
Mercado Abierto Electrónico S.A.

https://www.mae.com.ar

[dbtid]

Re: Problems implementing Rijndael

Ignacio De Marco wrote:
[color=blue]
> I'm not very familiar with C, so I would like to ask you how can use
> the algorithm Rijndael, suppousing that I want two simple functions (in C ANSI)
> implementing the CBC or ECB Modes (is the same for me, because I have
> both implementations in Delphi, but i need the same implementations in
> C for an AS400) with an interface similiar to this (in Object Pascal):
>
> function Encrypt(PlainTe xt: string; Key: string): string
>
> function Decrypt(Encrypt edText: string; Key: string): string
>
>
> Thanks in regard,
>
> Ignacio De Marco.
> Mercado Abierto Electrónico S.A.
> www.mae.com.ar[/color]

This is close to topical, so...

Object Pascal implements Strings as a sort of record
type, in operation similar to this:
Type String = record
length: byte;
bytes: array of char;
end;

C doesn't implement strings this way, so you have two choices:

a) build a type of your own that does something similar
b) pass the length of PlainText, Key and EncryptedText to the
appropriate functions, and then provide a way to get the
length of the result. You might do such like this

int Encrypt (void *PlainText, unsigned long ptLength,
void *Key, unsigned long kLength,
void **EncryptedStri ng, unsigned long *esLength);

int Decrypt (void *EncryptedText, unsigned long etLength,
void *Key, unsigned long kLength,
void **DecryptedStri ng, unsigned long *dsLength);

The last two parameters in each case are for you to return
a value to the caller.

e.g. in Encrypt, you would do something like
*EncryptedStrin g = encrypted_buffe r;
*esLength = encrypted_buffe r_len;


HTH

[Ivan Voras]

Re: Problems implementing Rijndael

Ignacio De Marco wrote:
[color=blue]
> I'm not very familiar with C, so I would like to ask you how can use
> the algorithm Rijndael, suppousing that I want two simple functions (in C ANSI)
> implementing the CBC or ECB Modes (is the same for me, because I have
> both implementations in Delphi, but i need the same implementations in
> C for an AS400) with an interface similiar to this (in Object Pascal):
>
> function Encrypt(PlainTe xt: string; Key: string): string
>
> function Decrypt(Encrypt edText: string; Key: string): string[/color]

What do you mean? Do you:

a) have C implementation( s) and want to use them in Delphi?
b) have Delphi implementation( s) with above declaration(s) and want to
use them in C?
c) none of the above, you just want an Rijndael implementation in C, no
matter how and which?

[Stephen Sprunk]

Re: Problems implementing Rijndael

"Ignacio De Marco" <ignaciodemarco @gmail.com> wrote in message
news:c4857042.0 409021032.27704 bdc@posting.goo gle.com...[color=blue]
> I'm not very familiar with C, so I would like to ask you how can use
> the algorithm Rijndael, suppousing that I want two simple functions (in C
> ANSI)
> implementing the CBC or ECB Modes (is the same for me, because I have
> both implementations in Delphi, but i need the same implementations in
> C for an AS400) with an interface similiar to this (in Object Pascal):
>
> function Encrypt(PlainTe xt: string; Key: string): string
>
> function Decrypt(Encrypt edText: string; Key: string): string[/color]

Take a look at OpenSSL's AES implementation.

S

--
Stephen Sprunk "Those people who think they know everything
CCIE #3723 are a great annoyance to those of us who do."
K5SSS --Isaac Asimov