Multi-node encryption and key delivery

A source device that is configured to encrypt content material for communication to a plurality of destination devices, each destination device of the plurality of destination devices having a private key and a public key of a public-private key pair, the source device comprising:

• a key generator that is configured to generate a plurality of keys based on the public keys of the plurality of destination devices,
• the plurality of keys including:
• a session key for encrypting the content material, and
• a plurality of partial keys corresponding to the plurality of destination devices, each partial key being configured to provide a decryption key corresponding to the session key when combined with the private key of each corresponding destination device and a public group key, and
• an encrypter that is configured to encrypt the content material based on the session key to create encrypted content material.

A method for decrypting encrypted content material from a source device that is encrypted based on a plurality of public keys, the method comprising:

• receiving the encrypted content material,
• receiving a first key that corresponds to a public key that is associated with the source device,
• receiving a second key that is based on a subset of the plurality of public keys, and
• creating a decryption key that is based upon the first key, the second key, and a private key of a public-private key pair whose corresponding public key is included in the plurality of public keys and is not included in the subset of the plurality of public keys, and
• decrypting the encrypted content material based on the decryption key.

A destination device comprising

• a receiver that is configured to receive encrypted content material, a first key, and a second key,
• the encrypted content material being encrypted based on a session key that is based on a plurality of public keys,
• the first key corresponding to a public group key, and
• the second key being based on a subset of the plurality of public keys,
• a key generator that is configured to create a decryption key based on the first key, the second key, and a private key of a public-private key pair whose corresponding public key is included in the plurality of public keys and is not included in the subset of the plurality of public keys, and
• a decrypter that is configured to decrypt the encrypted content material based on the decryption key.