Special encryption tools are developed in order to protect digital data stored in computer systems. Unfortunately, these tools are also used by computer crimes perpetrators in order to make digital evidence inaccessible to law enforcement. Correct application of modern cryptography often makes analysis of digital evidence technically impossible. Legal solutions to this problem are not fully effective and often violate the right against forced selfincrimination. It is crucial to develop tactics and techniques of digital evidence preservation and analysis that will allow, in certain circumstances, to obtain the data in unencrypted form. It is possible especially when the perpetrator failed to comply with all safety precautions concerning data encryption.