NIST SP 800-90A DRBG
基础
Recommendation for Random Number Generation Using Deterministic Random Bit Generators
non-deterministic random bit generators (NRBGs) 纯物理实现，不可预测
Deterministic Random Bit Generators (DRBGs) 使用算法生成
概要
初始化，reseed，生成随机数
{ internal state value, entropy input, additional input (optional) } => seed
initial_working_state = Instantiate_algorithm ( entropy_input , nonce , personalization_string, security_strength).
DRBG Instantiation : initialize with seed1 -> reseed with seed2 -> ...
Reseed_function ( state_handle, prediction_resistance_request, additional_input )
prediction_resistance_request: ( status , entropy_input) = Get_entropy_input ( security_strength , min_length , max_length)
Generate_function ( state_handle, requested_number_of_bits, requested_security_strength , prediction_resistance_request, additional_input)
类型
Hash_DRBG : hash函数用于instantiate, reseed and generate functions; 注意每次只使用同一种hash函数。
HMAC_DRBG : HMAC函数用于instantiate, reseed and generate functions; 注意有一个HMAC_DRBG_Update更新K, V；而K, V是用于hmac生成随机数的输入参数。
DRBG Mechanism Based on Block Ciphers
CTR_DRBG uses an approved block cipher algorithm in the counter mode，注意CTR_DRBG也有CTR_DRBG_Update更新K，V。而K，V是用于aes之类的算法生成随机数的输入参数。
Dual_EC_DRBG 由于后门问题，业界不推荐使用。
