Ransomware Encryption

posted on July 6th, 2014 by in Audio


Ransomware uses asymmetric encryption. When an attacker sends a message with encryption key value, user must give decryption key to decrypt the data, so learning about ransomware is important to be prevented against these attacks.

The value of encryption key is usually in the range from 35 to 58 bytes.

Any plaintext in the message is changed.

Message encrypted with symmetric cipher will have some header information like user name, encrypted password, and or comments that are used to display the message.

The value of encrypted header is usually a 64-bit integer.

Messages encrypted with symmetric cipher will have some key and symmetric key values like message content, encrypted message header, encrypted content of message header, and encrypted key.

The symmetric key value is normally encrypted with symmetric cipher with key length from 22 to 64 bytes.

This way attacker can not decrypt the header data after encrypted message header and content.

Encrypted data is only readable if user has given decryption key.

Cryptographic algorithm used to encrypt and decrypt symmetric cipher messages.

Encryption key should be set to “A” for AES and “B” for Twofish.

If the message does not have the correct encryption key, messages will be decrypted by a not even considered attacker.

The cipher is used for symmetric cipher messages.

Symmetric cipher for symmetric encryption is AES or Twofish with “A” encryption key and “B” decryption key.

Symmetric encryption works in which first user encrypts a message with her private key.

User later puts the message in the public key.

An attacker who doesn’t know public key encrypts the message with a randomly generated key, then sends the message with a not even considered adversary.

And the asymmetric encryption algorithm of symmetric cipher, decryption key and cipher block size (CBC) is chosen randomly.

If the public key is not properly created, symmetric encryption can not work.

AES encryption works in which first user encrypts the message with her private key.

AES encryption is one of the most used symmetric encryption algorithms in this malware class.

Symmetric encryption is applied symmetrically with same key.

The asymmetric key is asymmetric encryption algorithm.

Symmetric key can be created in two ways: symmetric-key cryptosystem or symmetric-key private key-generator.

S-box is the most popular encryption algorithm for symmetric encryption.

Symmetric key cryptosystem is composed of two keys public key and private key.

Public key is shared by user and decryptor.

The private key is secret and not ever shared with user.

When decrypting, public key is exchanged with the private key.

PuTTY’s symmetric cipher Cryptographic algorithm used to encrypt and decrypt symmetric cipher messages.

Cryptographic algorithm used to encrypt and decrypt symmetric cipher messages.

Encryption key should be set to “A” for AES and “B” for Twofish.

If the message does not have the correct encryption key, messages will be decrypted by a not even considered attacker.


bubble Comments Off

Comments are closed.