Patent ID: 7133524
Filing Date: 2006-11-07
Classification: H04L

Abstract:
1. A key installation system comprising a storage section and an LSI, wherein the storage section stores: a first encrypted key obtained by encrypting a final secret key using a first internal key; and a second encrypted key obtained by encrypting a second internal key using the first encrypted key, and the LSI stores a third encrypted key obtained by encrypting the first internal key using the second internal key, and receives the first and second encrypted keys from the storage section, the LSI comprising: a first decrypting circuit for decrypting the input second encrypted key using the input first encrypted key as key to output a key which is equivalent to the second internal key; a second decrypting circuit for decrypting the third encrypted key using the output of the first decrypting circuit as key to output a key which is equivalent to the first internal key; and a third decrypting circuit for decrypting the input first encrypted key using the output of the second decrypting circuit as key to generate a key which is equivalent to the final secret key.