MBEDTLS_CTR_DRBG_H macro

\file ctr_drbg.h This file contains definitions and functions for the CTR_DRBG pseudorandom generator. CTR_DRBG is a standardized way of building a PRNG from a block-cipher in counter mode operation, as defined in NIST SP 800-90A: Recommendation for Random Number Generation Using Deterministic Random Bit Generators. The Mbed TLS implementation of CTR_DRBG uses AES-256 (default) or AES-128 (if \c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled at compile time) as the underlying block cipher, with a derivation function. The security strength as defined in NIST SP 800-90A is 128 bits when AES-128 is used (\c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY enabled) and 256 bits otherwise, provided that #MBEDTLS_CTR_DRBG_ENTROPY_LEN is kept at its default value (and not overridden in mbedtls_config.h) and that the DRBG instance is set up with default parameters. See the documentation of mbedtls_ctr_drbg_seed() for more information.