Method and a device for encryption of images

A method of decoding image data of an image comprising the steps of:

• receiving an image bit stream comprising header information and independently decodable coding units of said image, said header information identifying first image data of said image as not encrypted and second image data of said image as encrypted;
• decoding all of at least one independently decodable coding unit of said first image data identified by said header information as not encrypted;
• sending a request for a decryption key for decrypting at least one independently decodable coding unit of said second image data identified by said header information as encrypted;
• receiving a decryption key upon said request;
• receiving upon said request at least one independently decodable coding unit of said second image data;
• decrypting said at least one upon said request received independently decodable coding unit of said second image data with said received decryption key.

A device for decoding image data of an image comprising:

• means for receiving an image bit stream of header information and independently decodable coding units of said image, said header information identifying first image data of said image as not encrypted and second image data of said image as encrypted;
• means for decoding all of at least one independently decodable coding unit of said first image data identified by said header information as not encrypted;
• means for sending a request for a decryption key for decrypting at least one independently decodable coding unit of said second image data identified by said header information as encrypted;
• means for receiving a decryption key upon said request;
• and
• means for decrypting at least one independently decodable coding unit of said second image data with said received decryption key.

A device for decoding image data of an image comprising:

• means for receiving an image bit stream of header information and independently decodable coding units of said image, said header information identifying first image data of said image as not encrypted and second image data of said image as encrypted;
• means for decoding all of at least one independently decodable coding unit of said first image data identified by said header information as not encrypted;
• means for sending a request for a decryption key for decrypting at least one independently decodable coding unit of said second image data identified by said header information as encrypted;
• means for receiving a decryption key upon said request;
• and
• means for receiving upon said request at least one independently decodable coding unit of said second image data;
• means for decrypting said at least one received independently decodable coding unit of said second image data with said received decryption key.

A device for encoding image data of an image comprising:

• means for sending encoded image data of said image in a bit stream;
• means for inserting header information in said image data bit stream, said header information identifying first image data as not encrypted, said header information identifying second image data as encrypted;
• means for sending condition information that includes a cost for decrypting second image data of said image;
• means for receiving a request for a decryption key for decrypting second image data of said image;
• means for sending a decryption key for decrypting the second image data of said image.