75 lines
1.3 KiB
Go
75 lines
1.3 KiB
Go
package crypto
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"encoding/hex"
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"github.com/aead/cmac"
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)
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func Create_k1() (string, error) {
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// 16 bytes = 128 bits
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b := make([]byte, 16)
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_, err := rand.Read(b)
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if err != nil {
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return "", err
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}
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str := hex.EncodeToString(b)
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return str, nil
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}
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// decrypt p with aes_dec
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func Aes_decrypt(key_sdm_file_read []byte, ba_p []byte) ([]byte, error) {
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dec_p := make([]byte, 16)
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iv := make([]byte, 16)
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c1, err := aes.NewCipher(key_sdm_file_read)
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if err != nil {
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return dec_p, err
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}
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mode := cipher.NewCBCDecrypter(c1, iv)
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mode.CryptBlocks(dec_p, ba_p)
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return dec_p, nil
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}
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func Aes_cmac(key_sdm_file_read_mac []byte, sv2 []byte, ba_c []byte) (bool, error) {
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c2, err := aes.NewCipher(key_sdm_file_read_mac)
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if err != nil {
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return false, err
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}
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ks, err := cmac.Sum(sv2, c2, 16)
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if err != nil {
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return false, err
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}
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c3, err := aes.NewCipher(ks)
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if err != nil {
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return false, err
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}
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cm, err := cmac.Sum([]byte{}, c3, 16)
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if err != nil {
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return false, err
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}
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ct := make([]byte, 8)
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ct[0] = cm[1]
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ct[1] = cm[3]
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ct[2] = cm[5]
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ct[3] = cm[7]
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ct[4] = cm[9]
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ct[5] = cm[11]
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ct[6] = cm[13]
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ct[7] = cm[15]
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res_cmac := bytes.Compare(ct, ba_c)
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if res_cmac != 0 {
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return false, nil
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}
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return true, nil
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}
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