mirror of https://github.com/mautrix/go.git
61 lines
1.5 KiB
Go
61 lines
1.5 KiB
Go
// Copyright (c) 2024 Sumner Evans
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package aescbc
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import (
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"crypto/aes"
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"crypto/cipher"
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"maunium.net/go/mautrix/crypto/pkcs7"
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)
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// Encrypt encrypts the plaintext with the key and IV. The IV length must be
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// equal to the AES block size.
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//
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// This function might mutate the plaintext.
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func Encrypt(key, iv, plaintext []byte) ([]byte, error) {
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if len(key) == 0 {
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return nil, ErrNoKeyProvided
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}
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if len(iv) != aes.BlockSize {
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return nil, ErrIVNotBlockSize
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}
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plaintext = pkcs7.Pad(plaintext, aes.BlockSize)
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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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cipher.NewCBCEncrypter(block, iv).CryptBlocks(plaintext, plaintext)
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return plaintext, nil
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}
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// Decrypt decrypts the ciphertext with the key and IV. The IV length must be
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// equal to the block size.
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//
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// This function mutates the ciphertext.
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func Decrypt(key, iv, ciphertext []byte) ([]byte, error) {
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if len(key) == 0 {
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return nil, ErrNoKeyProvided
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}
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if len(iv) != aes.BlockSize {
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return nil, ErrIVNotBlockSize
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}
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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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if len(ciphertext) < aes.BlockSize {
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return nil, ErrNotMultipleBlockSize
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}
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cipher.NewCBCDecrypter(block, iv).CryptBlocks(ciphertext, ciphertext)
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return pkcs7.Unpad(ciphertext), nil
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}
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