Statement of the NSA on the use of hash functions

Hash functions are functions where a fixed length output is assigned to any input. The function should have the property of unidirectionality and inconsistency.
Due to the rapid development in the area of crypto-analysis of hash functions (collision finding for some hash functions) and these functions are used in a number of security applications (e.g. electronic signature, etc.) as well as in many cryptographic products, the NSA issues the following statement:

  1. It is recommended to continue not to use hash function with output less than 160 bits (e.g. hash function MD4, MD5, RIPEMD, HAVAL-128, etc.).
  2. It is recommended that the preparation for the transition from the SHA-1 hash function to the new generation of SHA-2 class hash functions (SHA-224, SHA-256, SHA-384 and SHA-512) be started without delay within 3-5 years.
  3. it is recommended to examine all security applications and cryptographic products using hashing functions and to expertly assess the impact of the latest cryptoanalytical attacks on their security.