41 lines
639 B
Go
41 lines
639 B
Go
package crypto
|
|
|
|
import (
|
|
"crypto/sha1"
|
|
"encoding/hex"
|
|
"strings"
|
|
)
|
|
|
|
func twosComplement(p []byte) []byte {
|
|
carry := true
|
|
for i := len(p) - 1; i >= 0; i-- {
|
|
p[i] = byte(^p[i])
|
|
if carry {
|
|
carry = p[i] == 0xff
|
|
p[i]++
|
|
}
|
|
}
|
|
return p
|
|
}
|
|
|
|
// AuthDigest stolen from https://gist.github.com/toqueteos/5372776
|
|
func AuthDigest(elems ...[]byte) string {
|
|
h := sha1.New()
|
|
for _, elem := range elems {
|
|
h.Write(elem)
|
|
}
|
|
hash := h.Sum(nil)
|
|
|
|
negative := (hash[0] & 0x80) == 0x80
|
|
if negative {
|
|
hash = twosComplement(hash)
|
|
}
|
|
|
|
res := strings.TrimLeft(hex.EncodeToString(hash), "0")
|
|
if negative {
|
|
res = "-" + res
|
|
}
|
|
|
|
return res
|
|
}
|