Avoiding encryption of certain blocks in a deduplication vault

A method for avoiding encryption of certain blocks during a backup of a source storage into a deduplication vault storage, the method comprising:

• seeding the deduplication vault storage with common plain text blocks, the seeding the deduplication vault storage including:
• identifying an encrypted block stored in the deduplication vault storage that corresponds to multiple source storages;
• designating the encrypted block as a common block;
• obtaining a plain text block that corresponds to the encrypted block;
• replacing the encrypted block with the corresponding plain text block in the deduplication vault storage;
• and
• storing a hash value of the corresponding plain text block in a database or hash table such that the hash value is associated with the corresponding plain text block;
• and
• for each allocated plain text block in the source storage at a point in time, performing the following steps:
• analyzing the allocated plain text block to determine if the allocated plain text block is already stored in the deduplication vault storage;
• if the allocated plain text block is not stored in the deduplication vault storage, encrypting the allocated plain text block and analyzing the encrypted block to determine if the encrypted block is already stored in the deduplication vault storage;
• and
• if neither the allocated plain text block nor the encrypted block is already stored in the deduplication vault storage, storing the encrypted block in the deduplication vault storage.