JobCrypter is a threat that belongs to the groups of ransomware. It is designed to affect files on the infected system and encrypt them demanding payment for the restoration. JobCrypter originates in France, however it has already spread around the world. JobCrypter works in the similar way with other ransomware: it detects the files with most popular extensions and encrypts them adding .locked extension, after which the malware creates a text file.
CryptoLocker is a ransomware that squeezes money from users by encrypting the personal files with AES-265 and RSA algorithms. After the installation CryptoLocker inserts a randomly named executable file into %AppData% or %LocalAppData% folders. This executable is created for detecting the files for enciphering. It will change the extension of your media files and documents to .7z. CryptoLocker affects executables to prevent you from using the shadow copies.
UltraCrypter is updated version of previously described CryptXXX virus, that can be called CryptXXX 3.0 ransomware. Malware developers made some crucial changes, that are not very pleasant for potential victims. It still uses AES CBC 256-bit encryption algorithm, but now it adds .cryp1 extension to encrypted files. Ransom is 1.2 Bitcoins (around 500$). Bad news are, that now decryptors for CryptXXX does not work. That means the only chance to decrypt UltraCrypter-affected files is if you have external backup or enabled Windows service that will store previous versions of your files.
DMA-Locker or MadLocker is a ransomware that silently sneaks into your PC and makes it a disaster. After it has found a way to get on your computer, DMA-Locker starts searching the hard drives for important and mostly used files. Alongside with it, the ransomware displays a notification with detailed explanation of what has happened and with instruction for the user. It states that the files were hijacked and encrypted with unique code, which makes them unacceptable without Master Key that can be purchased.
.777 is file extension of files encrypted by recently appeared ransomware called 777 Virus or 777 Ransomware, that targets computers running Windows OS. Malware uses asymmetric encryption and generates two decryption keys (private and public). Hackers ask for ransom of $500 or $1500 to decrypt files. Usually users have to pay in BitCoins. Users need to send an e-mail to email@example.com to receive message like shown below, with instructions to pay the ransom.