NIST says agencies should begin move to stronger hashing tools
The National Institute of Standards and Technology is urging agencies to begin migrating away from the flawed SHA-1 hashing algorithm in favor of stronger algorithms.
A family of Secure Hashing Algorithms has been approved under Federal Information Processing Standard 180-2 for federal use to create a secure message digest'or a hash'of digital documents. Any alterations in the document will result in a different hash, so it can be used to time stamp, sign or otherwise authenticate a document. Like any cryptographic function, an algorithm's strength lies in its ability to resist attacks from increasingly powerful computers, and SHA-1 has been around since 1994.
Researchers reported last year that they had broken SHA-1 for some functions, prompting concern about its continued use.
'Due to advances in computing power, NIST already planned to phase out SHA-1 in favor of the larger and stronger hash functions (SHA-224, SHA-256, SHA-384 and SHA-512) by 2010,' NIST said at that time, and advised agencies to 'develop plans on a timely basis for an orderly transition.'
NIST strengthened its recommendation Wednesday, saying 'federal agencies should stop using SHA-1 for digital signatures, digital time stamping and other applications that require collision resistance as soon as practical.'
After 2010, SHA-1 can be used only for hash-based message authentication codes, key derivation functions and random number generators.
'Regardless of use, NIST encourages application and protocol designers to use the SHA-2 family of hash functions for all new applications and protocols,' NIST said.
William Jackson is a senior writer of GCN and the author of the CyberEye blog.