Yep, that solved it! That makes sense.
Thankyou so much!
On Wed, Nov 2, 2011 at 12:08 AM, re.est <re.est1...@gmail.com> wrote:
> Hello,
>
> I added *8 in length for both encrypt/decrypt call to make it bit length.
> AES_cfb1_encrypt(data, ciphertext, length*8, &key, iv, &num,
> AES_ENCRYPT);
>
> As you can see, cfb128_1 has uses bit as length in API
> void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
> size_t bits, const void *key, .......
>
> unlike other cfb APIs.
>
>
>
>
>
> On 11/01/2011 09:48 PM, Ananthasayanan Kandiah wrote:
>
> Hi,
>
> I would be grateful if you could expand on this. I've tried simply placing
> the bit length for the AES_set_encrypt_key call and it still produces the
> same result.
>
>
> Thanks,
> Anantha
>
> On Tue, Nov 1, 2011 at 8:10 PM, re est <re.est1...@gmail.com> wrote:
>
>> Hi,
>>
>> I have tried your code and replaced the length param with bit length
>> (*8) instead.
>> It worked. It seems that there are inconsistent with the usage of API.
>>
>> - re.est
>>
>> On Sun, Oct 30, 2011 at 4:55 PM, Ananthasayanan Kandiah
>> <ananthasaya...@obtino.com> wrote:
>> > Hi,
>> >
>> > I'm trying to use AES-CFB1 through the "low-level" calls. Here's the
>> example
>> > program I have come up with:
>> >
>> > #include <stdio.h>
>> > #include <string.h>
>> > #include <openssl/aes.h>
>> > #include <openssl/bio.h>
>> >
>> > #define KEY_SIZE 16
>> >
>> > int main(void)
>> > {
>> > int i;
>> > AES_KEY key;
>> > BIO* bio_out;
>> >
>> > unsigned char key_data[KEY_SIZE] = {
>> > 0xfe, 0xec, 0x82, 0x17, 0xb5, 0x1, 0x98, 0x6b,
>> > 0x5e, 0xf1, 0xb8, 0x6, 0x52, 0x74, 0x2e, 0x52
>> > };
>> >
>> > unsigned char iv[AES_BLOCK_SIZE];
>> >
>> > unsigned char const iv_data[AES_BLOCK_SIZE] = {
>> > 0x10, 0x8a, 0xc9, 0x30, 0xb7, 0xf2, 0x35, 0x21,
>> > 0xfb, 0xac, 0x6b, 0xdf, 0x80, 0x95, 0xeb, 0x1e
>> > };
>> >
>> > char* data = "Internet is a wonderful mechanism for making a
>> fool "
>> > "of yourself in front of a very large audience";
>> >
>> >
>> > int length = (int) strlen(data);
>> >
>> > int num = 0;
>> >
>> > /* Allocate some space for the ciphertext and plaintext */
>> > char* ciphertext = (char*) malloc(sizeof(char) * length);
>> > char* plaintext = (char*) malloc(sizeof(char) * length);
>> >
>> > /* Copy the IV data to the IV array */
>> > memcpy(iv, iv_data, AES_BLOCK_SIZE);
>> >
>> > /* Set the encrypt key structure using the predefined key */
>> > AES_set_encrypt_key(key_data, KEY_SIZE * 8, &key);
>> >
>> > /* Carry out the encryption */
>> > AES_cfb1_encrypt(data, ciphertext, length, &key, iv, &num,
>> AES_ENCRYPT);
>> >
>> > /* Setup output */
>> > bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
>> >
>> > BIO_printf(bio_out, "Original plaintext: %s\n\n", data);
>> >
>> > BIO_printf(bio_out, "Ciphertext: ");
>> >
>> > /* Print out the ciphertext */
>> > for (i = 0; i < length; i++)
>> > BIO_printf(bio_out, "%02x", ((unsigned char*)ciphertext)[i]);
>> >
>> > BIO_printf(bio_out, "\n\n");
>> >
>> > /* Start the decryption process */
>> >
>> > /* First, copy the original IV data back to the IV array - as it was
>> > overwritten
>> > * during the encryption process
>> > */
>> > memcpy(iv, iv_data, AES_BLOCK_SIZE);
>> >
>> > /* Reset how far we've gone through the IV */
>> > num = 0;
>> >
>> > /* Carry out the decryption */
>> > AES_cfb1_encrypt(ciphertext, plaintext, length, &key, iv, &num,
>> > AES_DECRYPT);
>> >
>> > BIO_printf(bio_out, "Recovered plaintext: ");
>> >
>> > /* print out the plaintext */
>> > for (i = 0; i < length; i++)
>> > BIO_printf(bio_out, "%c", ((unsigned char*)plaintext)[i]);
>> >
>> > BIO_printf(bio_out, "\n\n");
>> >
>> > BIO_free(bio_out);
>> >
>> > free(ciphertext);
>> > free(plaintext);
>> >
>> >
>> > return 0;
>> > }
>> >
>> > When I run it, the output which I receive is:
>> >
>> > Original plaintext: Internet is a wonderful mechanism for making a
>> foolof
>> > yourself in front of a very large audience
>> >
>> > Ciphertext:
>> >
>> 92c0883c54eb8df072b43278000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>> >
>> 000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>> >
>> > Recovered plaintext: Internet is
>> >
>> >
>> >
>> d:\ananthasayanan\stuff\projects\programming\openssl\openssl-1.0.0d\demos\crypto\low_level\ciphers\symmetric\aes\aes_cfb
>> > 1_128\x64\Release>aes_cfb1_128.exe
>> > Original plaintext: Internet is a wonderful mechanism for making a fool
>> of
>> > yourself in front of a very large audience
>> >
>> > Ciphertext:
>> >
>> 92c0883c54eb8df072b43278000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>> >
>> 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>> >
>> > Recovered plaintext: Internet is
>> >
>> > As you can see, the ciphertext that is produced is only 12 bytes in
>> length.
>> > Hence, the recovered plaintext has only 12 characters. I have had a
>> look at
>> > the source-code for AES_cfb1_encrypt and the comment says that the input
>> > should be "packed". What does this mean? Am I doing something wrong or
>> is
>> > there a bug with AES-CFB1?
>> >
>> >
>> > Thanks,
>> > Anantha
>> >
>> >
>> ______________________________________________________________________
>> OpenSSL Project http://www.openssl.org
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>>
>
>
>
