Friends,
I'm trying to verify that my encryption and decryption routines work ok. One
way I do it is to encrypt the data and save it to a file. The I feed the
encrypted file to my decryption routine and write the decrypted data to
another file. I compare the original data and the contents of the decrypted
file and they are same. So the routines work fine in tandem.
Another method I want to use it to encrypt the data and save it to a file.
Then I feed the encrypted file to Openssl command line to decrypt.
I get my encrypted data in the file rgconf_encrypted. Then I run the
following command:
openssl enc -d -aes-256-cbc -in rgconf_encrypted
I enter the decryption password "As different as chalk and cheese" which I
used to encrypt the data. But I get the error "bad magic number".
Am I missing something here ? I need to be able to use a simple phrase as my
encryption password so I can decrypt it on command line as well. Please
provide any pointers on what could be wrong here.
Below is the code for my encryption routine.
Thanks,
Kunal
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int encrypt(void)
{
EVP_CIPHER_CTX ctx;
unsigned char ibuf[1024],obuf[1024];
int rfd, wfd,ilen,olen,tlen;
unsigned char key32[] = "As different as chalk and cheese";
unsigned char iv[] = "As dark as pitch";
EVP_CIPHER_CTX_init(&ctx);
if(!EVP_CipherInit_ex(&ctx, EVP_aes_256_cbc(),NULL,key32, iv,AES_ENCRYPT) )
{
console_printf("Couldnt initialize cipher\n");
return 1;
}
/* read the original contents that are stored in file /etc/rgconf */
if((rfd = open("/etc/rgconf",O_RDONLY) ) == -1) {
console_printf("Couldnt open input file\n");
return 1;
}
/* open a file /et.rgconf_encrypted to store encrypted data */
if((wfd = creat("/etc/rgconf_encrypted",0644) ) == -1) {
console_printf("Couldn't open output file for writing\n");
return 1;
}
while((ilen = read(rfd,ibuf,1024) ) > 0) {
if(EVP_CipherUpdate(&ctx,obuf,&olen,ibuf,ilen)){
write(wfd,obuf,olen);
}
else {
console_printf("Encryption error\n");
return 1;
}
}
if(!EVP_CipherFinal_ex(&ctx,obuf+olen,&tlen)) {
console_printf("Trouble with padding the last block\n");
return 1;
}
write(wfd,obuf+olen,tlen);
EVP_CIPHER_CTX_cleanup(&ctx);
close(rfd);
close(wfd);
console_printf("AES 256 CBC encryption complete\n");
return 0;
}
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