Digital Envelopes

PKCS# 7 will digital envelopes as defined in terms of text, and to make the following interpretation: digital envelope contains encrypted content and encrypted for encryption this content key. Although often use the recipient's public key encryption keys to encrypt ", "but this is not necessary, can also use the sender and the receiver Shared symmetric key gets to encryption. When the recipient receive digital envelopes, first gets with your private key or decryption, get "Shared key encryption keys", again use this key unlock, original for.

Detailed information

Application and application methods

Digital envelopes are public-key cryptosystem in actually of an application, are using encryption techniques to ensure that only the specific provisions of the recipient can read communication content.

In digital envelope, information sender use semmetry key to encrypt information content, then will the symmetry with the recipient's key public-key encryption (this part to call the number envelope), will it and after together encrypted information sent to the recipient, receiving FangXianYong corresponding private key open digital envelopes, get symmetric key, then use the symmetric key unlock encrypted information. This technology security quite high. Digital envelopes mainly include digital envelope packing and digital envelopes dissembling, digital envelope packing is to use each other's public key will encryption/decryption key encryption process, only each other private key to the encrypted data (communication key) reduction; Digital envelopes dissembling is to use the private key will encrypt data declassified process.

Key replacement

Digital envelopes function similar to ordinary envelopes, ordinary envelope in legal constraints to ensure that only the recipient can read the content of the letter; Digital envelopes used the cipher technology guarantee prescribed receive talents can only reading information content. Digital envelopes adopted a symmetric cryptosystem and public-key cryptosystem. Information sender, first using randomly generated symmetric password encrypted message recipient, reuse encrypted password encrypted symmetrical, was called the symmetric password after digital envelope. In the message, if the receiving party declassified information, must first with their own decrypted digital envelopes, get symmetric password, can use semmetry password decryption information received. This helps to ensure that the data transmission authenticity and integrity.

In some important e-commerce transactions key must be replaced regularly, in order to solve the key problems, each replacement with symmetrical encryption technology and public key technical advantages, it overcomes the secret key encryption secret key distribution difficulties and public key encryption of problem, use longer encrypted two levels to obtain public key encryption technology flexibility and secret key technical efficiency. Information on use of a password sender to encrypt messages, thereby ensuring only prescribed intended recipients can read the content of the letter. Adopting digital envelopes technology, even encrypt files by others, because those illegal intercepts intercepts sender cannot get the communication of keys, so impossible to classify documents."