On Mon, Dec 17, 2012 at 11:50 PM, jeetendra gangele <gangele...@gmail.com> wrote: > U mean to say I can generate 64 bytes and then I can ignore last 8 > bytes? so I will get 56 bytes. > This value then I have to use as secret key for ECDH https://www.google.com/#q=truncated+hash
Be careful of ECDH because its anonymous or non-authenticated. NIST Special Publication 800-56A, Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography, might help guide you. Jeff > On 18 December 2012 09:57, Jeffrey Walton <noloa...@gmail.com> wrote: >> On Mon, Dec 17, 2012 at 11:16 PM, jeetendra gangele >> <gangele...@gmail.com> wrote: >>> Hi, >>> Do we have support for 448 bit hash value generation in openssl.? >>> I looked into the header file and I did not find functiobn related to that. >>> >>> Actually I need to compute shared key for ecdh and that should be 56 Bytes >>> long. >>> I could genearte the 20 byte 32 bytes but I need 56 bytes only. >> 448 bits is 56 bytes. You will have to use a smaller hash and iterate >> in a KDF-like fashion; or a larger hash and truncate. ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
