Patent ID: 7124302

Claim:
A virtual distribution environment comprising a host processing environment comprising: a central processing unit; main memory operatively connected to said central processing unit; mass storage operatively connected to said central processing unit and said main memory, said mass storage comprising: a secure storage area storing information at least some of which is encrypted, said information including one or more applications programs, each of said applications programs comprising one or more applications modules; a non-secure storage area storing information; programming which controls said host processing environment so as to load said applications modules from said secure storage area into said main memory, said programming further comprising programming which decrypts said applications modules during said loading process; and programming which removes at least certain of said application modules from said main memory as soon as execution of each said application module has at least temporarily completed, even if the area of said main memory occupied by said application module is not yet required for other information, wherein the duration of residency of at least certain applications modules in an unencrypted state in said main memory is limited so as to render analysis of said applications modules more difficult; wherein said secure storage area stores at least two encrypted applications modules, one of said encrypted applications modules having been encrypted using a first encryption key, and a second of said encrypted applications modules having been encrypted using a second encryption key different from said first encryption key.