mirror of https://github.com/mitchell/selfpass.git
100 lines
2.0 KiB
Go
100 lines
2.0 KiB
Go
package crypto
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"fmt"
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"io"
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"github.com/cloudflare/redoctober/padding"
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)
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func GenerateKeyFromPassword(pass []byte) ([]byte, error) {
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if len(pass) < 8 {
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return nil, fmt.Errorf("master password must be at least 8 characters")
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}
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for idx := 0; len(pass) < 32; idx++ {
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pass = append(pass, pass[idx])
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if idx == len(pass) {
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idx = 0
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}
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}
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return pass, nil
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}
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func CombinePasswordAndKey(pass, key []byte) ([]byte, error) {
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if len(pass) < 8 {
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return nil, fmt.Errorf("master password must be at least 8 characters")
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}
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if len(key) != 16 {
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return nil, fmt.Errorf("key was not of length 16")
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}
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for idx := 0; len(pass) < 16; idx++ {
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pass = append(pass, pass[idx])
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}
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return append(pass[:16], key...), nil
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}
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func CBCEncrypt(key []byte, plaintext []byte) ([]byte, error) {
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if len(key) != 32 {
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return nil, fmt.Errorf("key is not 32 bytes")
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}
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plaintext = padding.AddPadding(plaintext)
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if len(plaintext)%aes.BlockSize != 0 {
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return nil, fmt.Errorf("plaintext is not a multiple of the block size")
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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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ciphertext := make([]byte, aes.BlockSize+len(plaintext))
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iv := ciphertext[:aes.BlockSize]
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if _, err := io.ReadFull(rand.Reader, iv); err != nil {
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return nil, err
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}
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mode := cipher.NewCBCEncrypter(block, iv)
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mode.CryptBlocks(ciphertext[aes.BlockSize:], plaintext)
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return ciphertext, nil
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}
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func CBCDecrypt(key []byte, ciphertext []byte) ([]byte, error) {
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if len(key) != 32 {
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return nil, fmt.Errorf("key is not 32 bytes")
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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, err
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}
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iv := ciphertext[:aes.BlockSize]
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ciphertext = ciphertext[aes.BlockSize:]
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if len(ciphertext)%aes.BlockSize != 0 {
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return nil, fmt.Errorf("ciphertext is not a multiple of the block size")
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}
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mode := cipher.NewCBCDecrypter(block, iv)
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mode.CryptBlocks(ciphertext, ciphertext)
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return padding.RemovePadding(ciphertext)
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}
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