func (alg *AesGcm) Encrypt(aad, plainText, cek []byte) (iv, cipherText, authTag []byte, err error) {
cekSizeBits := len(cek) << 3
if cekSizeBits != alg.keySizeBits {
return nil, nil, nil, errors.New(fmt.Sprintf("AesGcm.Encrypt(): expected key of size %v bits, but was given %v bits.", alg.keySizeBits, cekSizeBits))
}
if iv, err = arrays.Random(12); err != nil {
return nil, nil, nil, err
}
var block cipher.Block
if block, err = aes.NewCipher(cek); err != nil {
return nil, nil, nil, err
}
var aesgcm cipher.AEAD
if aesgcm, err = cipher.NewGCM(block); err != nil {
return nil, nil, nil, err
}
cipherWithTag := aesgcm.Seal(nil, iv, plainText, aad)
cipherText = cipherWithTag[:len(cipherWithTag)-aesgcm.Overhead()]
authTag = cipherWithTag[len(cipherWithTag)-aesgcm.Overhead():]
return iv, cipherText, authTag, nil
}
func (alg *AesCbcHmac) Encrypt(aad, plainText, cek []byte) (iv, cipherText, authTag []byte, err error) {
cekSizeBits := len(cek) << 3
if cekSizeBits != alg.keySizeBits {
return nil, nil, nil, errors.New(fmt.Sprintf("AesCbcHmac.Encrypt(): expected key of size %v bits, but was given %v bits.", alg.keySizeBits, cekSizeBits))
}
hmacKey := cek[0 : len(cek)/2]
aesKey := cek[len(cek)/2:]
if iv, err = arrays.Random(16); err != nil {
return nil, nil, nil, err
}
var block cipher.Block
if block, err = aes.NewCipher(aesKey); err != nil {
return nil, nil, nil, err
}
padded := padding.AddPkcs7(plainText, 16)
cipherText = make([]byte, len(padded), cap(padded))
mode := cipher.NewCBCEncrypter(block, iv)
mode.CryptBlocks(cipherText, padded)
authTag = alg.computeAuthTag(aad, iv, cipherText, hmacKey)
return iv, cipherText, authTag, nil
}
func (alg *AesGcmKW) WrapNewKey(cekSizeBits int, key interface{}, header map[string]interface{}) (cek []byte, encryptedCek []byte, err error) {
if kek, ok := key.([]byte); ok {
kekSizeBits := len(kek) << 3
if kekSizeBits != alg.keySizeBits {
return nil, nil, errors.New(fmt.Sprintf("AesGcmKW.WrapNewKey(): expected key of size %v bits, but was given %v bits.", alg.keySizeBits, kekSizeBits))
}
if cek, err = arrays.Random(cekSizeBits >> 3); err != nil {
return nil, nil, err
}
var iv []byte
if iv, err = arrays.Random(12); err != nil {
return nil, nil, err
}
var block cipher.Block
if block, err = aes.NewCipher(kek); err != nil {
return nil, nil, err
}
var aesgcm cipher.AEAD
if aesgcm, err = cipher.NewGCM(block); err != nil {
return nil, nil, err
}
cipherWithTag := aesgcm.Seal(nil, iv, cek, nil)
cipherText := cipherWithTag[:len(cipherWithTag)-aesgcm.Overhead()]
authTag := cipherWithTag[len(cipherWithTag)-aesgcm.Overhead():]
header["iv"] = base64url.Encode(iv)
header["tag"] = base64url.Encode(authTag)
return cek, cipherText, nil
}
return nil, nil, errors.New("AesGcmKW.WrapNewKey(): expected key to be '[]byte' array")
}
func (alg *RsaOaep) WrapNewKey(cekSizeBits int, key interface{}, header map[string]interface{}) (cek []byte, encryptedCek []byte, err error) {
if pubKey, ok := key.(*rsa.PublicKey); ok {
if cek, err = arrays.Random(cekSizeBits >> 3); err == nil {
encryptedCek, err = rsa.EncryptOAEP(alg.sha(), rand.Reader, pubKey, cek, nil)
return
}
return nil, nil, err
}
return nil, nil, errors.New("RsaOaep.WrapNewKey(): expected key to be '*rsa.PublicKey'")
}
func (alg *AesKW) WrapNewKey(cekSizeBits int, key interface{}, header map[string]interface{}) (cek []byte, encryptedCek []byte, err error) {
if kek, ok := key.([]byte); ok {
kekSizeBits := len(kek) << 3
if kekSizeBits != alg.keySizeBits {
return nil, nil, errors.New(fmt.Sprintf("AesKW.WrapNewKey(): expected key of size %v bits, but was given %v bits.", alg.keySizeBits, kekSizeBits))
}
if cek, err = arrays.Random(cekSizeBits >> 3); err == nil {
encryptedCek, err = aes.KeyWrap(cek, kek)
return
}
return nil, nil, err
}
return nil, nil, errors.New("AesKW.WrapNewKey(): expected key to be '[]byte' array")
}
func (alg *Pbse2HmacAesKW) WrapNewKey(cekSizeBits int, key interface{}, header map[string]interface{}) (cek []byte, encryptedCek []byte, err error) {
if passphrase, ok := key.(string); ok {
algId := []byte(header["alg"].(string))
iterationCount := 8192
var saltInput []byte
if saltInput, err = arrays.Random(12); err != nil {
return nil, nil, err
}
header["p2c"] = iterationCount
header["p2s"] = base64url.Encode(saltInput)
salt := arrays.Concat(algId, []byte{0}, saltInput)
kek := kdf.DerivePBKDF2([]byte(passphrase), salt, iterationCount, alg.keySizeBits, alg.prf())
return alg.aesKW.WrapNewKey(cekSizeBits, kek, header)
}
return nil, nil, errors.New("Pbse2HmacAesKW.WrapNewKey(): expected key to be 'string' array")
}
