Abstract: A system and method for efficient transfer of encrypted data over a low-bandwidth network. A backup server and a client computer are coupled to one another via a first network. The backup server is coupled to a remote data storage via another network, such as the Internet, also referred to as a cloud. The backup server encrypts received data for backup from the client computer. Cryptography segment and sub-segment sizes may be chosen that are aligned on a byte boundary with one another and with selected backup segment and sub-segment sizes used by backup software on the remote data storage. A selected cryptography algorithm has a property of allowing a given protected sub-segment with the cryptography sub-segment size to be decrypted by initially decrypting an immediate prior protected sub-segment that has the same cryptography sub-segment size. Therefore, the size of data transmitted via the cloud may be smaller than the cryptography segment size.

Abstract: A system and method for efficient transfer of encrypted data over a low-bandwidth network. A backup server and a client computer are coupled to one another via a first network. The backup server is coupled to a remote data storage via another network, such as the Internet, also referred to as a cloud. The backup server encrypts received data for backup from the client computer. Cryptography segment and sub-segment sizes may be chosen that are aligned on a byte boundary with one another and with selected backup segment and sub-segment sizes used by backup software on the remote data storage. A selected cryptography algorithm has a property of allowing a given protected sub-segment with the cryptography sub-segment size to be decrypted by initially decrypting an immediate prior protected sub-segment that has the same cryptography sub-segment size. Therefore, the size of data transmitted via the cloud may be smaller than the cryptography segment size.