All three types of cryptography schemes have unique function mapping to specific．For example,the symmetric key approach（本题）is typically used for the encryption of data providing（ ）,whereas asymmetric key cryptography is maidy used in key（ ）and nonrepudiation,thereby providing confidentiality and authentication．The hash（ ）（noncryptic）,on the other hand,does not provide confidentiality but provides message integrity,and cryptographic hash algorithms provide message（ ）and identity of peers during transport over insecure channels．

All three types of cryptography schemes have unique function mapping to specific．For example,the symmetric key approach（本题）is typically used for the encryption of data providing（ ）,whereas asymmetric key cryptography is maidy used in key（ ）and nonrepudiation,thereby providing confidentiality and authentication．The hash（ ）（noncryptic）,on the other hand,does not provide confidentiality but provides message integrity,and cryptographic hash algorithms provide message（ ）and identity of peers during transport over insecure channels．