i need to encrypt an input of 16 bytes with a plain key of 16 bytes with 2 method of encryption CBC and ECB.
i have 2 files with :
1.txt : CB18D7B3101924314051647990A9C4E1
2.txt : 0000000000000000F05FBEFD564A164D
i need after encrypt the second key with the first key , to have a 3.txt file with result
like :
3.txt : D057E1DB9458102CFD06AFCA5504E598
thanks to help me with a program or command to do that.
It seems that the question is how to encrypt the data 2 with the key 1 to obtain the encrypted data 3. Further it looks like the encryption method is CAST, see:CAST.
Where:
1: CB18D7B3101924314051647990A9C4E1
2: 0000000000000000F05FBEFD564A164D
3: D057E1DB9458102CFD06AFCA5504E598
The methods ECB and CBC can not both be used at the same time. See Block cipher mode of operation.
Related
I am using OpenSSL to encrypt my data. Assuming I have 3 rows of data(for simplicty)
0123456789
987654321
121212121
After encrypting, I get
Salted__èøm¬è!^¬ü
?‘¡ñ1•yÈ}, .◊¬ó≤|Úx$mø©
However, when I copy using my Mac's CMD+ C, then I paste in another file to be decrpyted, i get this error
bad decrypt
0076160502000000:error:1C80006B:Provider routines:ossl_cipher_generic_block_final:wrong final block length:providers/implementations/ciphers/ciphercommon.c:429:
However if I did not copy and paste the encrpyted data, it can be decrypted properly. I believe is due to the spacings changed.. Is it that we cannot copy the data to another file to be decrpyted and MUST use the exact file that was encrpyted?
Implement the Caesar Cipher algorithm to encrypt and decrypt a file contents using C language. The cipher basic all use algorithm . Your program should have two C files named encrypt.c and decrypt.c that contains encrypt() and decrypt() functions correspondently for the purpose. In the encryption.c file, use the main() function to take input from a “input.txt” file and store the encrypted message to “enc_msg.txt” file. In the decryption.c file, use the main() function to take input from a “enc_msg.txt” file and store the decrypted message to “dec_msg.txt” file and print the decrypted message in console output as well. The key is 3.
Thanks
Create two .c files encrypt.c and decrypt.c
Create sample data input.txt file
Run your encrypt program to create output file enc_msg.txt from input.txt file
Run your decrypt program to create output file dec_msg.txt from input enc_msg.txt file
So you need to create 3 files encrypt.c decrypt.c and input.txt
And running your programs will generate two more files enc_msg.txt and dec_msg.txt
I am trying to decrypt programmatically encrypted file using OpenSSL. OpenSSL was used to encrypt the file and I know both the function and the key that was used:
//This declaration is just figurative
const char keybuf = "12345678";
// Prepare the key for use with DES_cfb64_encrypt
DES_cblock key2;
DES_key_schedule schedule;
// keybuf is the string key used as password
memcpy(key2, keybuf, 8);
DES_set_odd_parity(&key2);
DES_set_key_checked(&key2, &schedule);
int n = 0;
DES_cfb64_encrypt( ..., ..., length, &schedule, &key2, &n, DES_ENCRYPT );
First I converted the file to binary from base64 (which is how it's packed):
cat data.b64 | base64 --decode > data.cr
Now when I run command line on encrypted data (assuming des-cfb is algorighm I need):
openssl enc -d -des-cfb -in data.cr -out data.decr -k 12345678
this is what I get:
bad magic number
So what I'm doing wrong here? Maybe I converted the file wrongly from base64?
Which openssl command is equivalent to DES_cfb64_encrypt function?
None
The CFB mode is a parametrized mode and the 64 in DES_cfb64_encrypt sets the size of the shift register or segment to 64 bit. The commandline interface only supports 3 segment sizes for CFB mode which are 1 bit, 8 bit and size of the cipher block size (64 bit for DES). Those three parametrized modes are incompatible between each other and they cannot be used to decrypt ciphertexts that were encrypted with CFB-64.
I am looking at this page on how to validate HMAC implementation on a platform: http://csrc.nist.gov/groups/STM/cavp/
Test Vectors:
HMAC Test Vectors - These files provide an electronic version of the test vectors
that can be used to informally verify the correctness of an HMAC algorithm
implementation using the HMACVS. However, use of these vectors does not
take the place of validation obtained through the Cryptographic Algorithm
Validation Program (CAVP).
So I open up the file and view the test values:
http://pastebin.com/phJ4C0Fx
it is thousands of lines long but this is the start.
I focus on the first values:
[L=20]
Count = 0
Klen = 10
Tlen = 10
Key = 82f3b69a1bff4de15c33
Msg = fcd6d98bef45ed6850806e96f255fa0c8114b72873abe8f43c10bea7c1df706f10458e6d4e1c9201f057b8492fa10fe4b541d0fc9d41ef839acff1bc76e3fdfebf2235b5bd0347a9a6303e83152f9f8db941b1b94a8a1ce5c273b55dc94d99a171377969234134e7dad1ab4c8e46d18df4dc016764cf95a11ac4b491a2646be1
Mac = 1ba0e66cf72efc349207
My understanding is that with a key and value that openssl would get the mac, however I am not getting the same mac as that above?
echo -n "<Msg here>" | openssl sha1 -hmac "82f3b69a1bff4de15c33"
(stdin)= 981c64f70b07634e01b3800447e6431dddb42530
Any ideas on what I am doing wrong? i am also just guessing sha1, other values don't match either, I don't know how to take from the file what way I should be doing this. The various lengths, and the count. How do I use this information?
I'm trying to decrypt a XOR encrypted file, after running the key length test using xortool I got this key: "fallen"..
# python xortool.py -c 00 /cygdrive/c/Users/Me/Desktop/ch3.bmp
The most probable key lengths:
1: 10.6%
3: 11.6%
6: 18.5%
9: 8.8%
12: 13.8%
15: 6.6%
18: 10.4%
24: 8.1%
30: 6.4%
36: 5.2%
Key-length can be 3*n
1 possible key(s) of length 6:
fallen
Whatever is there a way to decipher the file (a bmp file) and get the original one, using tools like openssl or gpg?? Do they have a XOR operation?
Neither OpenSSL nor GPG have such XOR functionality that I'm aware of, however writing a program to do it yourself should be trivial.
Given that you know that the file is a .bmp, you should be able to use this fact to decrypt the file quite easily, especially given that .bmp files have a well defined structure. For example, the first two bytes when decrypted should be 0x42, 0x4D (that's ASCII BM), and the following 4 bytes are the (big-endian) size of the entire file in bytes, so you should be able to get at least 6 bytes of the key immediately.
Since you already have xortool, just use xortool-xor from the xortool distribution:
python xortool/xortool-xor -s fallen /cygdrive/c/Users/Me/Desktop/ch3.bmp > decoded.bmp
Also note that xortool itself saves the decoded output in the xortool_out folder, so after using xortool to find the key, you could just do:
mv xortool_out/0_fallen decoded.bmp