You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
54 lines
1.2 KiB
54 lines
1.2 KiB
3 years ago
|
package crypto
|
||
|
|
|
||
|
|
import (
|
||
|
|
"crypto/rsa"
|
||
|
|
// #nosec
|
||
|
|
//
|
||
|
|
// Allowing sha1 because it is used in MTProto itself.
|
||
|
|
"crypto/sha1"
|
||
|
|
"math/big"
|
||
|
|
)
|
||
|
|
|
||
|
|
// RSAKeyBits is RSA key size.
|
||
|
|
//
|
||
|
|
// Can be used as rsa.GenerateKey(src, RSAKeyBits).
|
||
|
|
const RSAKeyBits = 2048
|
||
|
|
|
||
|
|
const (
|
||
|
|
rsaLen = 256
|
||
|
|
rsaWithHashLen = 255
|
||
|
|
rsaDataLen = rsaWithHashLen - sha1.Size
|
||
|
|
)
|
||
|
|
|
||
|
|
// RSAPublicDecrypt recovers the message digest from the raw signature
|
||
|
|
// using the signer’s RSA public key.
|
||
|
|
//
|
||
|
|
// See also OpenSSL’s RSA_public_decrypt with RSA_NO_PADDING.
|
||
|
|
func RSAPublicDecrypt(pub *rsa.PublicKey, sig []byte) ([]byte, error) {
|
||
|
|
k := pub.Size()
|
||
|
|
if k < 11 || k != len(sig) {
|
||
|
|
return nil, rsa.ErrVerification
|
||
|
|
}
|
||
|
|
|
||
|
|
c := new(big.Int).SetBytes(sig)
|
||
|
|
e := big.NewInt(int64(pub.E))
|
||
|
|
m := new(big.Int).Exp(c, e, pub.N)
|
||
|
|
|
||
|
|
return m.Bytes(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func rsaEncrypt(data []byte, key *rsa.PublicKey) []byte {
|
||
|
|
z := new(big.Int).SetBytes(data)
|
||
|
|
e := big.NewInt(int64(key.E))
|
||
|
|
c := new(big.Int).Exp(z, e, key.N)
|
||
|
|
res := make([]byte, rsaLen)
|
||
|
|
c.FillBytes(res)
|
||
|
|
return res
|
||
|
|
}
|
||
|
|
|
||
|
|
func rsaDecrypt(data []byte, key *rsa.PrivateKey, to []byte) bool {
|
||
|
|
c := new(big.Int).SetBytes(data)
|
||
|
|
m := new(big.Int).Exp(c, key.D, key.N)
|
||
|
|
return FillBytes(m, to)
|
||
|
|
}
|