52 lines
1.4 KiB
Go
52 lines
1.4 KiB
Go
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package secretbox
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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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"crypto/sha256"
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"errors"
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"fmt"
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)
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func Encrypt(master, plaintext string) ([]byte, error) {
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block, err := aes.NewCipher(deriveKey(master))
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if err != nil {
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return nil, fmt.Errorf("create secret cipher: %w", err)
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}
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aead, err := cipher.NewGCM(block)
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if err != nil {
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return nil, fmt.Errorf("create secret AEAD: %w", err)
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}
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nonce := make([]byte, aead.NonceSize())
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if _, err := rand.Read(nonce); err != nil {
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return nil, fmt.Errorf("generate secret nonce: %w", err)
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}
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return aead.Seal(nonce, nonce, []byte(plaintext), []byte("go-loose-oidc-v1")), nil
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}
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func Decrypt(master string, ciphertext []byte) (string, error) {
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block, err := aes.NewCipher(deriveKey(master))
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if err != nil {
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return "", fmt.Errorf("create secret cipher: %w", err)
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}
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aead, err := cipher.NewGCM(block)
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if err != nil {
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return "", fmt.Errorf("create secret AEAD: %w", err)
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}
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if len(ciphertext) < aead.NonceSize() {
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return "", errors.New("encrypted secret is truncated")
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}
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nonce, sealed := ciphertext[:aead.NonceSize()], ciphertext[aead.NonceSize():]
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plaintext, err := aead.Open(nil, nonce, sealed, []byte("go-loose-oidc-v1"))
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if err != nil {
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return "", errors.New("encrypted secret cannot be opened")
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}
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return string(plaintext), nil
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}
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func deriveKey(master string) []byte {
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sum := sha256.Sum256([]byte("go-loose/oidc/" + master))
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return sum[:]
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}
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