400 in various embodiments the fifth portion 422 may contain data recording the decryption state journaling data temporary data used in the decryption and combinations thereof fig5 a 5 d illustrate the decryption of the virtual disc image 406 u2032 408 u2032 of a virtual disc 400 when booted from a virtual machine fig5 a is identical with fig4 e in a first step the virtual machine boots on the virtual disc 400 and boots into the virtual disc master boot record 410 next the master boot record 410 loads the decryption program 412 the decryption program 412 then requests cryptographic credentials or a password for use for decrypting the encrypted virtual disc image 406 u2032 408 u2032 in fig5 b the decryption process is illustrated two different views of the virtual disc 400 are shown blocks labeled 500 are decrypted blocks of the second part of the virtual disc image blocks labeled 502 are encrypted blocks of the second part of the virtual disc image in the top view shown in fig5 b only the block labeled 4 is a decrypted block 500 the remainder of the second part of the virtual disc image is encrypted the bottom part of fig5 b shows that all blocks of the second part of the virtual disc image 408 are decrypted blocks 500 fig5 c shows further progress in decrypting the virtual.