srvdav/vendor/github.com/abbot/go-http-auth/md5crypt.go

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package auth
import "crypto/md5"
import "strings"
const itoa64 = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
var md5_crypt_swaps = [16]int{12, 6, 0, 13, 7, 1, 14, 8, 2, 15, 9, 3, 5, 10, 4, 11}
type MD5Entry struct {
Magic, Salt, Hash []byte
}
func NewMD5Entry(e string) *MD5Entry {
parts := strings.SplitN(e, "$", 4)
if len(parts) != 4 {
return nil
}
return &MD5Entry{
Magic: []byte("$" + parts[1] + "$"),
Salt: []byte(parts[2]),
Hash: []byte(parts[3]),
}
}
/*
MD5 password crypt implementation
*/
func MD5Crypt(password, salt, magic []byte) []byte {
d := md5.New()
d.Write(password)
d.Write(magic)
d.Write(salt)
d2 := md5.New()
d2.Write(password)
d2.Write(salt)
d2.Write(password)
for i, mixin := 0, d2.Sum(nil); i < len(password); i++ {
d.Write([]byte{mixin[i%16]})
}
for i := len(password); i != 0; i >>= 1 {
if i&1 == 0 {
d.Write([]byte{password[0]})
} else {
d.Write([]byte{0})
}
}
final := d.Sum(nil)
for i := 0; i < 1000; i++ {
d2 := md5.New()
if i&1 == 0 {
d2.Write(final)
} else {
d2.Write(password)
}
if i%3 != 0 {
d2.Write(salt)
}
if i%7 != 0 {
d2.Write(password)
}
if i&1 == 0 {
d2.Write(password)
} else {
d2.Write(final)
}
final = d2.Sum(nil)
}
result := make([]byte, 0, 22)
v := uint(0)
bits := uint(0)
for _, i := range md5_crypt_swaps {
v |= (uint(final[i]) << bits)
for bits = bits + 8; bits > 6; bits -= 6 {
result = append(result, itoa64[v&0x3f])
v >>= 6
}
}
result = append(result, itoa64[v&0x3f])
return append(append(append(magic, salt...), '$'), result...)
}