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encryption key & IV are only the state at start
of encryption, this state evolves during encryption, so that if you store
only the key and IV at the beginning of first packet, you must decrypt in
same order as when you encrypted, this way the state evolves equivalently and it
works
Regards
Armel
----- Original Message -----
Sent: Tuesday, September 07, 2004 2:13
PM
Subject: RE: 3 des implementation - help
needed
Thanks. I have tried
the same. And end up in same results,
But if I decrypt
buffers (sizes of 4352, 2048, 1024) in the same sequence as that of
encryption. It is giving proper output. ( it is matching with the original
buffer).
What could be the
reason?
-----Original
Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Tuesday, September 07, 2004 1:56
PM
To:
[EMAIL PROTECTED]
Subject: Re: 3 des implementation - help
needed
p.s. out must be
allocated char[(i_len+(8-i_len%8))]
BOOL
SSL_encrypt_key(EVP_CIPHER_CTX ctx, char *in, char *out, int i_len,int *o_len
){
int o_final_len;
EVP_EncryptUpdate(&ctx,out, o_len, in, i_len);
EVP_EncryptFinal(&ctx,out+*o_len, &o_final_len);
*o_len+=o_final_len;
return SUCCESS;
}
BOOL
SSL_decrypt_key(EVP_CIPHER_CTX ctx,char *in, char *out,
int i_len,int *o_len){
int o_final_len;
EVP_DecryptUpdate(&ctx,out, o_len, in, i_len);
EVP_DecryptFinal(&ctx,out+*o_len, &o_final_len);
*o_len+=o_final_len;
return SUCCESS;
}
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----- Original Message -----
Sent:
Tuesday, September 07, 2004 9:29 AM
Subject: 3 des
implementation - help needed
Hi.,
I am planning to use 3 des implementation. I am encrypting the chunk
of data (1024/2048/4352 bytes) with randomly generated keys and vectors. I
have stored the keys and vectors in non volatile memory or a file. During
decryption I have taken the key and vector from the file or non volatile
memory. The first 8 bytes are overwritten. Means the decrypted data is not
matching!!!
In this
case I am having two applications which are running independently. I have
used EVP_des_ede3_cfb() – cipher for encryption.
I would
like to know that apart from key and vector used for encryption do I need to
store something else also for decryption?
P.S: If
I have a sample application in which decryption and encryption are not done,
in that case Unencrypted data is matching with the original
one!!
Thanks.,
Sakthi
S G
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