ref: 74d91a0021de012908cfdb35fb61a1473a376130
dir: /lib/crypto/hmac.myr/
use std use "sha256" use "hash" pkg crypto = type hmac(@h) :: hash @h = struct inner : @h outer : @h ;; const hmacsha256 : (key : byte[:], msg : byte[:] -> byte[32]) const hmacsha224 : (key : byte[:], msg : byte[:] -> byte[28]) generic hmacinit : (hmac : hmac(@h)#, key : byte[:] -> void) generic hmacadd : (hmac : hmac(@h)#, msg : byte[:] -> void) generic hmacfin : (hmac : hmac(@h)#, dst : byte[:] -> void) ;; const hmacsha256 = {key, msg var hmac : hmac(sha256) var r : byte[32] hmacinit(&hmac, key) hmacadd(&hmac, msg) hmacfin(&hmac, r[:]) -> r } const hmacsha224 = {key, msg var hmac : hmac(sha224) var r : byte[28] hmacinit(&hmac, key) hmacadd(&hmac, msg) hmacfin(&hmac, r[:]) -> r } generic hmacinit = {hmac : hmac(@h)#, key :: hash @h /* for now, max block size is 128 bytes */ var k : byte[128], ik : byte[128], ok : byte[128] var hashsz, blksz hashsz = impl(Hashsz, @h) blksz = impl(Blocksz, @h) std.slfill(k[:blksz], 0) if key.len > blksz /* abuse the inner hasher a bit */ hinit(&hmac.inner) hadd(&hmac.inner, key) hfin(&hmac.inner, k[:hashsz]) else std.slcp(k[:key.len], key) ;; for var i = 0; i < blksz; i++ ik[i] = k[i] ^ 0x36 ok[i] = k[i] ^ 0x5c ;; hinit(&hmac.inner) hinit(&hmac.outer) hadd(&hmac.inner, ik[:blksz]) hadd(&hmac.outer, ok[:blksz]) } generic hmacadd = {hmac, msg hadd(&hmac.inner, msg) } generic hmacfin = {hmac : hmac(@h)#, dst :: hash @h hfin(&hmac.inner, dst) hadd(&hmac.outer, dst) hfin(&hmac.outer, dst) }