The basic concepts of encryption and related terms
Encryption technology classification
Symmetric encryption techniques and principles and implementation
Principle and asymmetric encryption technology
PGP algorithm
Encryption Summary: Information is an important resource in today's society; information the user needs is confidential, complete and true; modern information systems must have the information technology security measures; information is encrypted information security group to measure the One
Encryption: the plaintext into cipher text under the control of a particular key and algorithm
Encryption security services: confidentiality, integrity, non-repudiation
Academic language password: plaintext, ciphertext, algorithms, keys, encryption, decryption
The basic idea of encryption: displacement, displacement
Displacement and replacement are reversible, easy recovery information
Displacement, replacement used in modern cryptographic algorithms
The principle of symmetric encryption algorithms: a traditional password encryption & private key encryption algorithm // symmetric encryption process is fast
Symmetric encryption key length from 40bits to 168bits
Famous encryption algorithms:
DES / 3DES // IBM developed a block or a block cipher key is fixed 56bit, insecure, operation of the DES block 64bit ciphertext block, the DES algorithm is performed three times, called 3DES, increased encryption complexity (each different encrypted key control)
IDEA International Data Encryption Algorithm // packet is 64 bits, the key length is 128 bits, software faster than DES
RC series (RC2, RC4, RC5) // key length, packet length, the number of iterations can be considered set
CAST
Blowfish / Twofish // variable length key, the encryption process is less than 5KB storage
AES Advanced Encryption Standard
Asymmetric cryptography: public key encryption late appearance ratio of the private key
Private key encryption using the same key to encrypt and encryption information; key encryption uses two keys, one for encryption and one for encryption. And can not be deduced from each other. // save the private key needs security, public disclosure, encryption is slow, you can use them in conjunction with symmetric encryption
The famous private key encryption algorithm:
RSA // key length of 512 to 2048 (more than 8000), DES slower than the software implementation of RSA 100 times ... At present the main features of the RSA encryption and digital signatures
DH // solve the problem of key release, to achieve key exchange in IPsec
// PGP e-mail encryption software is based on RSA can provide encryption services, but also provide a digital signature.
// encryption technology confidentiality, integrity and authentication of the sender of the data source.
// hash function MD5 and SHA
// digital envelope
//digital signature
// integrity verification = HASH function, WinMD5 tool
//Authentication