Case data encryption - digital envelope technology
such as A to transfer an article can not be described to B, not in clear text transmission, but the article can not be described by a relatively large number of high-definition picture without code, content is large. At this time, the digital envelope techniques may be employed.
(1) the data content can not be described by the article "symmetric encryption" encryption, symmetric encryption to generate the ciphertext data content. - generating a symmetric key []
(2) B of the asymmetric public key encryption to A, to retain their own private key, A] to [symmetric key encrypted with the public
(3) A ciphertext encrypted data with [ ] symmetric key data to the network B
(. 4) B is decrypted by the private key of the asymmetric key [], then [] decrypt the symmetric key is not described in the article, Hey Hey. . .
Digital encryption drawback:
if C as a senior good father, do not want B to see the indescribable article then hey hey, the information C intercept A, the article will not be described modified to health inspirational good text, use [good father symmetric key] encryption inspirational ciphertext formed article, while giving good father [] symmetric key encrypted with the public key to B, after the inspirational ciphertext with a public key encryption symmetric key] [Papa transmitted through the network to the B, B, and decrypts come out. Since B inspirational reading, he got a job IT.
I made up a piece.
such as A to transfer an article can not be described to B, not in clear text transmission, but the article can not be described by a relatively large number of high-definition picture without code, content is large. At this time, the digital envelope techniques may be employed.
(1) the data content can not be described by the article "symmetric encryption" encryption, symmetric encryption to generate the ciphertext data content. - generating a symmetric key []
(2) B of the asymmetric public key encryption to A, to retain their own private key, A] to [symmetric key encrypted with the public
(3) A ciphertext encrypted data with [ ] symmetric key data to the network B
(. 4) B is decrypted by the private key of the asymmetric key [], then [] decrypt the symmetric key is not described in the article, Hey Hey. . .
Digital encryption drawback:
if C as a senior good father, do not want B to see the indescribable article then hey hey, the information C intercept A, the article will not be described modified to health inspirational good text, use [good father symmetric key] encryption inspirational ciphertext formed article, while giving good father [] symmetric key encrypted with the public key to B, after the inspirational ciphertext with a public key encryption symmetric key] [Papa transmitted through the network to the B, B, and decrypts come out. Since B inspirational reading, he got a job IT.
I made up a piece.