mirror of
https://github.com/PretendoNetwork/friends.git
synced 2026-08-01 23:54:32 -05:00
58 lines
1.3 KiB
Go
58 lines
1.3 KiB
Go
package utility
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import (
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"crypto/aes"
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"crypto/cipher"
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"encoding/hex"
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"fmt"
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"github.com/PretendoNetwork/friends/globals"
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"github.com/PretendoNetwork/nex-go/v2/types"
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)
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func ccmDecrypt(key, nonce, ciphertext []byte) ([]byte, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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L := 15 - len(nonce)
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counter := make([]byte, aes.BlockSize)
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counter[0] = byte(L - 1)
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copy(counter[1:1+len(nonce)], nonce)
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stream := cipher.NewCTR(block, counter)
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padded := make([]byte, aes.BlockSize+len(ciphertext))
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copy(padded[aes.BlockSize:], ciphertext)
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out := make([]byte, len(padded))
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stream.XORKeyStream(out, padded)
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return out[aes.BlockSize:], nil
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}
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func DecryptMiiData(miiData types.Buffer) ([]byte, error) {
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if len(miiData) < 0x70 {
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return nil, fmt.Errorf("Mii data length is incorrect: %d", len(miiData))
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}
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nonce := miiData[:8]
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ciphertext := miiData[8 : 8+0x58]
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key, err := hex.DecodeString(globals.Config.MiiDecryptKey)
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if err != nil {
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return nil, err
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}
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content, err := ccmDecrypt(key, append(append([]byte{}, nonce...), 0, 0, 0, 0), ciphertext)
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if err != nil {
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return nil, err
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}
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result := make([]byte, 0, len(content)+len(nonce))
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result = append(result, content[:12]...)
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result = append(result, nonce...)
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result = append(result, content[12:]...)
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return result, nil
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}
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