I have some plain text encrypted with Triple XOR and then Triple DES. I also have the key. How do I manage to uncover the plain text?
Here is a handy tool: Online decrypt tool
Related
I'm doing a CTF challenge and I got the text file with the flag but it's encrypted in XOR.
I've been looking everywhere trying to find how to decrypt it and I just can't figure it out.
0x3bc10x3cca0x26d40x12d80x2e50x3cdb0x18f20x1a9d0x29f20x149a0x7cd0
and i belive this is a key = 5DAD
I tried to remove the 0x and decrypt it in python scripts I found but nothing works.
What am I missing?
i have to create an aes-256 key and store it in a .pem file. I am using RAND_bytes() to simply create a 256 bit random key. After this how can i save this to a pem file.
I have looked at Reading and writing rsa keys to a pem file in C and openssl pem. But i am not working with RSA keys.
I suspect my task is much simpler like create pem from base64 but not much help.
PS: This key will be used to encrypt a self signed digital certificate.
EDIT: looking around more i found that i could use bio to covert to pem, something likePEM_write_bio_PrivateKey but it takes EVP_PKEY format as argument. So how can i convert char buf to EVP_PKEY. i found d2i_PublicKey but it involves RSA and am unsure how RSA would fit into picture here.
AES key is just a random byte array. You can simple store the bytes in a file without any structure.
You can convert aes key to .pem by using PEMWriter class of bouncyCastle library.
http://www.bouncycastle.org/documentation.html
i'm using this portion of code
char encrypted_text[1024];
RSA_public_encrypt(sizeof(message), message, encrypted_text, rsa, RSA_PKCS1_OAEP_PADDING);
printf("encrypted text: %s\n", encrypted_text);
and the optput is something like this:
�v0��뷾��s�E�Z��N\����6~��:�&���� /����~ͯ���L��d�Ǡ��
E��[�h�U.vH2F1Qb^)�g� ,a�Ҩ�x vU|�>�ˢ=W�ő��
�\��g
it's possible to eliminate � symbols??
The string isn't printing well because it's binary data, not text. It's not meant to be human readable.
A common way to make binary data text-friendly is to base64 encode it. Base64 encoding converts binary data into a string of ASCII characters. The encoded text still isn't human readable, so it'll still look like gobbledygook when you print it, but it'll at least be easy on the eyes, easy to paste into text files, easy to e-mail around.
See this Stack Overflow question for ways to do base64 encoding/decoding in C.
I have a problem with encrypting a string.
I have the command to encrypt a file using OpenSSL.
But I wanted to know the encrypt the string not the File.
The command for encrypting a file is:
system("openssl des3 -e -nosalt -in %s -out %s -k %s > /tmp/sys; cat /tmp/sys", src, dest, key);
where src and dest are the two file names.
what are the options available with OPEN SSL.
In above in and out are options for encrypting a text file.
I need the option to encrypting character array variable.
As pointed out on another question (by someone who dug through the code more than I did):
https://opensource.conformal.com/viewgit/?a=viewblob&p=cyphertite&h=899259f8ba145c11087088ec83153db524031800&hb=6782c6839d847fbed0aed8c55917e78b5684110f&f=cyphertite/ct_crypto.c
has the code you need to use OpenSSL natively to perform encryption/decryption in your app.
Happy hacking!
I have a text file that I have to sign with RSA private key and then append this signature and do an AES encryption over this "text file+signature".
For demonstration reasons I am testing such an encrypted file.
I am writing a simple program in C to do the following:
First do an RSA sign(1024 bit) on a text file.
Then append the signature to the text file
Then do an AES encryption over the file.
Then perform the AES decryption
Then remove the 128 byte signature from the file.
Then do an RSA verification of the original text file and the text file after decryption.
Here are my questions:
Is it a good idea to append a binary signature to a text file?
If no what is the general way this is done?
I tried a simple program to do the above but I always get one or two junk characters on AES decryption and therefore RSA verification fails.
Do please suggest.
an AES decrypt of such a file and then remove the 128 byte(1024 bit modulus) signature.
The ad-hoc standard for embedding crypto information in text files was introduced by Privacy Enhanced Mail some time ago: Basically the binary information is encoded in base-64 and appended to the text file along with a header line to identify the "snip" point for the added content.
Here is a sample of what it typically looks like (this chunk would be added to the end of the existing text file)
-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 4,ENCRYPTED
Content-Domain: RFC822
DEK-Info: DES-CBC,F8143EDE5960C597
Originator-ID-Symmetric: linn#zendia.enet.dec.com,,
Recipient-ID-Symmetric: linn#zendia.enet.dec.com,ptf-kmc,3
Key-Info: DES-ECB,RSA-MD2,9FD3AAD2F2691B9A,
B70665BB9BF7CBCDA60195DB94F727D3
Recipient-ID-Symmetric: pem-dev#tis.com,ptf-kmc,4
Key-Info: DES-ECB,RSA-MD2,161A3F75DC82EF26,
E2EF532C65CBCFF79F83A2658132DB47
LLrHB0eJzyhP+/fSStdW8okeEnv47jxe7SJ/iN72ohNcUk2jHEUSoH1nvNSIWL9M
8tEjmF/zxB+bATMtPjCUWbz8Lr9wloXIkjHUlBLpvXR0UrUzYbkNpk0agV2IzUpk
J6UiRRGcDSvzrsoK+oNvqu6z7Xs5Xfz5rDqUcMlK1Z6720dcBWGGsDLpTpSCnpot
dXd/H5LMDWnonNvPCwQUHt==
-----END PRIVACY-ENHANCED MESSAGE-----