pass: pass.go annotate

Update to new crypto import path. Our the Go crypto library is now located at golang.org/x/crypto, so we need to update to use that instead of Google Code.

paddy@0	1 package pass
paddy@0	2
paddy@0	3 import (
paddy@0	4 "crypto/rand"
paddy@0	5 "crypto/subtle"
paddy@0	6 "hash"
paddy@0	7 "time"
paddy@0	8
paddy@2	9 "golang.org/x/crypto/pbkdf2"
paddy@0	10 )
paddy@0	11
paddy@0	12 func Create(h func() hash.Hash, iters int, passphrase []byte) (result, salt []byte, err error) {
paddy@0	13 salt = make([]byte, 32)
paddy@0	14 _, err = rand.Read(salt)
paddy@1	15 if err != nil {
paddy@0	16 return []byte{}, []byte{}, err
paddy@0	17 }
paddy@0	18 result = Check(h, iters, passphrase, salt)
paddy@0	19 return result, salt, err
paddy@0	20 }
paddy@0	21
paddy@0	22 func CalculateIterations(h func() hash.Hash) (int, error) {
paddy@0	23 hashInstance := h()
paddy@0	24 salt := make([]byte, 32)
paddy@0	25 _, err := rand.Read(salt)
paddy@0	26 if err != nil {
paddy@0	27 return 0, err
paddy@0	28 }
paddy@0	29 iter := 2048
paddy@0	30 var duration time.Duration
paddy@0	31 for duration < time.Second {
paddy@0	32 iter = iter * 2
paddy@0	33 timeStart := time.Now()
paddy@0	34 pbkdf2.Key([]byte("password1"), salt, iter, hashInstance.Size(), h)
paddy@0	35 duration = time.Since(timeStart)
paddy@0	36 }
paddy@0	37 return iter, nil
paddy@0	38 }
paddy@0	39
paddy@0	40 func Check(h func() hash.Hash, iters int, passphrase, salt []byte) []byte {
paddy@0	41 hashInstance := h()
paddy@0	42 return pbkdf2.Key(passphrase, salt, iters, hashInstance.Size(), h)
paddy@0	43 }
paddy@0	44
paddy@0	45 func Compare(candidate, expectation []byte) bool {
paddy@0	46 candidateConsistent := make([]byte, len(candidate))
paddy@0	47 expectationConsistent := make([]byte, len(candidate))
paddy@0	48 subtle.ConstantTimeCopy(1, candidateConsistent, candidate)
paddy@0	49 subtle.ConstantTimeCopy(1, expectationConsistent, expectation)
paddy@0	50 return subtle.ConstantTimeCompare(candidateConsistent, expectationConsistent) == 1
paddy@0	51 }

pass

pass/pass.go