System and method for decrypting content samples including distinct encryption chains

摘要

Embodiments may be configured to receive a protected version of content that includes multiple encrypted content samples. In various embodiments, each encrypted content sample includes multiple encrypted blocks. For a given encrypted content sample, different sets of encrypted blocks in that sample may form different encryption chains. The protected version of the content may further include decryption information for decrypting the encrypted content samples. The decryption information may include at least some initialization vectors generated dependent upon non-content information that is not included in the protected version of the content. The non-content information may be from a different protected version of the content. Embodiments may be configured to use the decryption information to decrypt one or more of the encrypted content samples.

主权项

1. A computer-implemented method, comprising:
receiving a protected version of content that comprises multiple encrypted content samples, each encrypted content sample comprising multiple encrypted blocks, for a given encrypted content sample, different sets of the encrypted blocks in that sample forming different encryption chains, the protected version of the content further comprising decryption information for decrypting the encrypted content samples, the decryption information including at least some initialization vectors generated dependent upon non-content information not included in the protected version of the content, said non-content information being from a different protected version of the content, and at least one of the initialization vectors included in the decryption information corresponding to a discarded encrypted block; and using the decryption information to decrypt one or more of the encrypted content samples.