zer.ooo/service
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Actually make Padding work

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This commit is contained in:
eater 2019-08-11 15:24:04 +02:00
parent c537f79ccc
commit a683caaf76
Signed by: eater
GPG key ID: 656785D50BE51C0A
2 changed files with 31 additions and 14 deletions
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29
crypto.go
View file

@ -43,7 +43,7 @@ func DecryptAndVerify(input []byte, key *rsa.PrivateKey, pub *rsa.PublicKey, sig
body := make([]byte, len(encBody)) body := make([]byte, len(encBody))
dec := cipher2.NewCBCDecrypter(cipher, iv) dec := cipher2.NewCBCDecrypter(cipher, iv)
dec.CryptBlocks(body, encBody) dec.CryptBlocks(body, encBody)
err = json.Unmarshal(unpad(body), v) err = json.Unmarshal(Unpad(body), v)
if err != nil { if err != nil {
return err return err
@ -112,16 +112,16 @@ func EncryptAndSign(v interface{}, key *rsa.PrivateKey, pub *rsa.PublicKey, sign
enc := cipher2.NewCBCEncrypter(cipher, iv) enc := cipher2.NewCBCEncrypter(cipher, iv)
enc.CryptBlocks(encBody, body) enc.CryptBlocks(encBody, body)
copy(pad(encBody), encBody[len(encBody):]) copy(encBody[len(encBody):], Pad(encBody))
writer.Write([]byte(hex.EncodeToString(encBody))) writer.Write([]byte(hex.EncodeToString(encBody)))
return nil return nil
} }
func pad(body []byte) []byte { func Pad(body []byte) []byte {
rest := len(body) % 8 rest := len(body) % 8
if rest == 0 { if rest == 0 {
padLen := getPad(body) padLen := GetPad(body)
if padLen != 0 { if padLen != 0 {
return []byte{8, 8, 8, 8, 8, 8, 8, 8} return []byte{8, 8, 8, 8, 8, 8, 8, 8}
} }
@ -129,36 +129,37 @@ func pad(body []byte) []byte {
return []byte{} return []byte{}
} }
pad := make([]byte, rest) padLen := 8 - rest
pad := make([]byte, padLen)
for i := 0; i < rest; i++ { for i := 0; i < padLen; i++ {
pad[i] = byte(rest) pad[i] = byte(padLen)
} }
return pad return pad
} }
func getPad(body []byte) int { func GetPad(body []byte) int {
lastIndex := len(body) - 1 lastIndex := len(body) - 1
padLen := body[lastIndex] padLen := int(body[lastIndex])
if 1 < padLen && padLen < 9 { if 1 < padLen && padLen < 9 {
isPadding := true isPadding := true
for i := byte(0); i < padLen; i++ { for i := 0; i < padLen; i++ {
if body[-i] != padLen { if body[lastIndex-i] != byte(padLen) {
isPadding = false isPadding = false
break break
} }
} }
if isPadding { if isPadding {
return int(padLen) return padLen
} }
} }
return 0 return 0
} }
func unpad(body []byte) []byte { func Unpad(body []byte) []byte {
return body[:len(body)-getPad(body)] return body[:len(body)-GetPad(body)]
} }

16
crypto_test.go
View file

@ -8,6 +8,22 @@ import (
"testing" "testing"
) )
func TestPadding(t *testing.T) {
x := []byte{0, 0, 0}
x = append(x, service.Pad(x)...)
padLen := service.GetPad(x)
if padLen != 5 {
t.Errorf("Failed adding/measuring padding, Pad(%v, len=%d)", x, padLen)
}
y := service.Unpad(x)
if len(y) != 3 {
t.Errorf("Failed padding and unpadding, Pad(%v), Unpad(%v)", x, y)
}
}
func TestSingleRound(t *testing.T) { func TestSingleRound(t *testing.T) {
keyA, _ := rsa.GenerateKey(rand.Reader, 4096) keyA, _ := rsa.GenerateKey(rand.Reader, 4096)
keyB, _ := rsa.GenerateKey(rand.Reader, 4096) keyB, _ := rsa.GenerateKey(rand.Reader, 4096)