Security experts will tell you that no proprietary software is safe. Corporations can collude with the government to introduce backdoors, and Microsoft is known to have a cozy relationship with law enforcement. They provide software like COFEE https://en.wikipedia.org/wiki/Computer_Online_Forensic_Evidence_Extractor Open source software is safer because it can be reviewed by independent experts. TrueCrypt is open source. GPG is open source. BitLocker is not open source, and some of the Windows ports of GPG may not be open source, so be careful, and choose open source security solutions over proprietary ones.