85 lines
2.4 KiB
Go
85 lines
2.4 KiB
Go
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package util
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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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"encoding/base64"
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"errors"
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"fmt"
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)
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func ConvertToBase64(input []byte) (string, error) {
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if input == nil {
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return "", errors.New("cannot convert to base64 with nil input")
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}
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return base64.URLEncoding.EncodeToString(input), nil
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}
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func ConvertFromBase64(input string) ([]byte, error) {
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if input == "" {
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return nil, errors.New("cannot convert from base64 with blank input")
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}
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return base64.URLEncoding.DecodeString(input)
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}
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// EncryptAndEncode encrypts an input with a secret key and returns the base64 encoded and encrypted string
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func EncryptAndEncode(input string, secretKey string) (string, error) {
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var err error
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var block cipher.Block
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if block, err = aes.NewCipher([]byte(secretKey)); err != nil {
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return "", fmt.Errorf("cannot create cipher for encrypting: %w", err)
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}
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var gcm cipher.AEAD
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if gcm, err = cipher.NewGCM(block); err != nil {
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return "", fmt.Errorf("cannot create gcm for encrypting: %w", err)
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}
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nonce := make([]byte, gcm.NonceSize())
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if _, err = rand.Read(nonce); err != nil {
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return "", fmt.Errorf("cannot read nonce for encrypting: %w", err)
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}
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ciphertext := gcm.Seal(nonce, nonce, []byte(input), nil)
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var encoded string
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if encoded, err = ConvertToBase64(ciphertext); err != nil {
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return "", fmt.Errorf("cannot encode encrypted input: %w", err)
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}
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return encoded, nil
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}
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// DecryptAndDecode decodes and decrypts a given base64 string and returns the decrypted plain text
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func DecryptAndDecode(base64Encoded string, secretKey string) (string, error) {
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var decoded []byte
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var err error
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if decoded, err = ConvertFromBase64(base64Encoded); err != nil {
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return "", fmt.Errorf("cannot decode encoded input: %w", err)
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}
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decodedCipherText := string(decoded)
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var block cipher.Block
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if block, err = aes.NewCipher([]byte(secretKey)); err != nil {
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return "", fmt.Errorf("cannot create cipher for decrypting: %w", err)
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}
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var gcm cipher.AEAD
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if gcm, err = cipher.NewGCM(block); err != nil {
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return "", fmt.Errorf("cannot create gcm for decrypting: %w", err)
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}
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nonceSize := gcm.NonceSize()
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nonce, decodedCipherText := decodedCipherText[:nonceSize], decodedCipherText[nonceSize:]
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var plaintext []byte
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if plaintext, err = gcm.Open(nil, []byte(nonce), []byte(decodedCipherText), nil); err != nil {
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return "", fmt.Errorf("cannot decrypt: %w", err)
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}
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return string(plaintext), nil
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}
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