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55 lines
1.3 KiB
55 lines
1.3 KiB
package crypto |
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import ( |
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"crypto/aes" |
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"io" |
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"github.com/gotd/ige" |
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"github.com/gotd/td/bin" |
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) |
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func countPadding(l int) int { return 16 + (16 - (l % 16)) } |
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// encryptMessage encrypts plaintext using AES-IGE. |
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func (c Cipher) encryptMessage(k AuthKey, plaintext *bin.Buffer) (EncryptedMessage, error) { |
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offset := len(plaintext.Buf) |
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plaintext.Buf = append(plaintext.Buf, make([]byte, countPadding(offset))...) |
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if _, err := io.ReadFull(c.rand, plaintext.Buf[offset:]); err != nil { |
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return EncryptedMessage{}, err |
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} |
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messageKey := MessageKey(k.Value, plaintext.Buf, c.encryptSide) |
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key, iv := Keys(k.Value, messageKey, c.encryptSide) |
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aesBlock, err := aes.NewCipher(key[:]) |
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if err != nil { |
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return EncryptedMessage{}, err |
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} |
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msg := EncryptedMessage{ |
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AuthKeyID: k.ID, |
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MsgKey: messageKey, |
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EncryptedData: make([]byte, len(plaintext.Buf)), |
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} |
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ige.EncryptBlocks(aesBlock, iv[:], msg.EncryptedData, plaintext.Buf) |
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return msg, nil |
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} |
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// Encrypt encrypts EncryptedMessageData using AES-IGE to given buffer. |
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func (c Cipher) Encrypt(key AuthKey, data EncryptedMessageData, b *bin.Buffer) error { |
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b.Reset() |
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if err := data.EncodeWithoutCopy(b); err != nil { |
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return err |
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} |
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msg, err := c.encryptMessage(key, b) |
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if err != nil { |
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return err |
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} |
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b.Reset() |
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if err := msg.Encode(b); err != nil { |
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return err |
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} |
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return nil |
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}
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