Cryptographic Choices

aCrypt first used Twofish, one of the Advanced Encryption Standard (AES) candidate algorithim. This algorithm was designed by Counterpane systems and Bruce Schneier. Since October 2000, aCrypt uses Rijndael, the AES winning algorithm. The random number generator uses Knuth's additive generator. The key length is currently hard-coded to 128 bits, a length that is generally considered to be unbreakable by brute force in the current stated of the technology. This limit was also chosen to comply with the current French legislation. Please remember that the strength of a symmetric cryptographic algorithm such as the one used by aCrypt depends only on the secrecy of the password. Do not send it along the attached file !

Other Safety Considerations

As developers of IDA Pro, the leading malware analysis tool, we are very much aware of the fact that executable attachments are a vector for viruses, worms and trojans. Therefore the auto-extractible aCrypt executable is self-checking at different levels : it is designed to warn you if it has been modified, corrupted or infected by a virus. Please note that a attacks directed specifically against any software are always possible : that's why we are not going to tell you that there will never be any risk. As a general rule

• always use a virus scanner, update frequently.
• aCrypt will warn you if it has been modified in any way.
• do not run executable attachments from unknown sources.
• do not hesitate contacting us if you suspect foul play.

aCrypt is developed by DataRescue as a public service. DataRescue develops and publishes the world's most advanced disassembler.