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crypto.go
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crypto.go
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package crypto
/*
* Copyright 2020-2021 Aldelo, LP
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import (
"crypto"
"crypto/aes"
"crypto/cipher"
"crypto/hmac"
"crypto/md5"
"crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"io"
"strings"
"golang.org/x/crypto/bcrypt"
"golang.org/x/crypto/scrypt"
util "github.com/aldelo/common"
"github.com/aldelo/common/ascii"
)
// ================================================================================================================
// KEY HELPERS
// ================================================================================================================
// Generate32ByteRandomKey will generate a random 32 byte key based on passphrase and random salt,
// passphrase does not need to be any specific length
func Generate32ByteRandomKey(passphrase string) (string, error) {
// validate passphrase
if len(passphrase) == 0 {
return "", errors.New("Passphrase is Required")
}
// generate salt
salt := make([]byte, 32)
// populate salt
if _, err1 := io.ReadFull(rand.Reader, salt); err1 != nil {
return "", err1
}
// generate key
key, err2 := scrypt.Key([]byte(passphrase), salt, 32768, 8, 1, 32)
if err2 != nil {
return "", err2
}
return util.ByteToHex(key), nil
}
// ================================================================================================================
// MD5 HELPERS
// ================================================================================================================
// Md5 hashing
func Md5(data string, salt string) string {
b := []byte(data + salt)
return fmt.Sprintf("%X", md5.Sum(b))
}
// ================================================================================================================
// SHA256 HELPERS
// ================================================================================================================
// Sha256 hashing (always 64 bytes output)
func Sha256(data string, salt string) string {
b := []byte(data + salt)
return fmt.Sprintf("%X", sha256.Sum256(b))
}
// ================================================================================================================
// BCRYPT HELPERS
// ================================================================================================================
// PasswordHash uses BCrypt to hash the given password and return a corresponding hash,
// suggested cost = 13 (440ms),
// if cost is left as 0, then default 13 is assumed
func PasswordHash(password string, cost int) (string, error) {
if cost <= 0 {
cost = 13
} else if cost < 12 {
cost = 12
} else if cost > 31 {
cost = 31
}
b, err := bcrypt.GenerateFromPassword([]byte(password), cost)
if err != nil {
return "", err
}
return string(b), nil
}
// PasswordVerify uses BCrypt to verify the input password against a prior hash version to see if match
func PasswordVerify(password string, hash string) (bool, error) {
err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
if err != nil {
return false, err
}
return true, nil
}
// ================================================================================================================
// AES-GCM HELPERS
// ================================================================================================================
// AesGcmEncrypt will encrypt using aes gcm 256 bit,
// passphrase must be 32 bytes, if over 32 bytes, it be truncated,
// encrypted data is represented in hex value
func AesGcmEncrypt(data string, passphrase string) (string, error) {
// ensure data has value
if len(data) == 0 {
return "", errors.New("Data to Encrypt is Required")
}
// ensure passphrase is 32 bytes
// note: passphrase is just ascii, not hex, client should not convert to hex
if len(passphrase) < 32 {
return "", errors.New("Passphrase Must Be 32 Bytes")
}
// cut the passphrase to 32 bytes only
passphrase = util.Left(passphrase, 32)
// convert data and passphrase into byte array
text := []byte(data)
key := []byte(passphrase)
// generate a new aes cipher using the 32 bytes key
c, err1 := aes.NewCipher(key)
// on error stop
if err1 != nil {
return "", err1
}
// using gcm (Galois/Counter Mode) for symmetric key cryptographic block ciphers
// https://en.wikipedia.org/wiki/Galois/Counter_Mode
gcm, err2 := cipher.NewGCM(c)
// on error stop
if err2 != nil {
return "", err2
}
// create a new byte array the size of the nonce,
// which must be passed to Seal
nonce := make([]byte, gcm.NonceSize())
// populate our nonce with a cryptographically secure random sequence
if _, err3 := io.ReadFull(rand.Reader, nonce); err3 != nil {
return "", err3
}
// encrypt our text using Seal function,
// Seal encrypts and authenticates plaintext,
// authenticates the additional data and appends the result to dst,
// returning the updated slice,
// the nonce must be NonceSize() bytes long and unique for all time, for a given key
// return util.ByteToHex(gcm.Seal(nonce, nonce, text, nil)), nil
return util.ByteToHex(gcm.Seal(nonce, nonce, text, nil)), nil
}
// AesGcmDecrypt will decrypt using aes gcm 256 bit,
// passphrase must be 32 bytes, if over 32 bytes, it be truncated
func AesGcmDecrypt(data string, passphrase string) (string, error) {
// ensure data has value
if len(data) == 0 {
return "", errors.New("Data to Decrypt is Required")
}
// ensure passphrase is 32 bytes
// note: passphrase is just ascii, not hex, client should not convert to hex
if len(passphrase) < 32 {
return "", errors.New("Passphrase Must Be 32 Bytes")
}
// cut the passphrase to 32 bytes only
passphrase = util.Left(passphrase, 32)
// convert data and passphrase into byte array
text, err := util.HexToByte(data)
if err != nil {
return "", err
}
key := []byte(passphrase)
// create aes cipher
c, err1 := aes.NewCipher(key)
// on error stop
if err1 != nil {
return "", err1
}
// create gcm (Galois/Counter Mode) to decrypt
gcm, err2 := cipher.NewGCM(c)
// on error stop
if err2 != nil {
return "", err2
}
// create nonce
nonceSize := gcm.NonceSize()
if len(text) < nonceSize {
return "", errors.New("Cipher Text Smaller Than Nonce Size")
}
// get cipher text
nonce, text := text[:nonceSize], text[nonceSize:]
// decrypt cipher text
plaintext, err3 := gcm.Open(nil, nonce, text, nil)
// on error stop
if err3 != nil {
return "", err3
}
// return decrypted text
return string(plaintext), nil
}
// ================================================================================================================
// AES-CFB HELPERS
// ================================================================================================================
// AesCfbEncrypt will encrypt using aes cfb 256 bit,
// passphrase must be 32 bytes, if over 32 bytes, it be truncated,
// encrypted data is represented in hex value
func AesCfbEncrypt(data string, passphrase string) (string, error) {
// ensure data has value
if len(data) == 0 {
return "", errors.New("Data to Encrypt is Required")
}
// ensure passphrase is 32 bytes
if len(passphrase) < 32 {
return "", errors.New("Passphrase Must Be 32 Bytes")
}
// cut the passphrase to 32 bytes only
passphrase = util.Left(passphrase, 32)
// convert data and passphrase into byte array
text := []byte(data)
key := []byte(passphrase)
// generate a new aes cipher using the 32 bytes key
c, err1 := aes.NewCipher(key)
// on error stop
if err1 != nil {
return "", err1
}
// iv needs to be unique, but doesn't have to be secure,
// its common to put it at the beginning of the cipher text
cipherText := make([]byte, aes.BlockSize+len(text))
iv := cipherText[:aes.BlockSize]
if _, err2 := io.ReadFull(rand.Reader, iv); err2 != nil {
return "", err2
}
// encrypt
stream := cipher.NewCFBEncrypter(c, iv)
stream.XORKeyStream(cipherText[aes.BlockSize:], text)
// return encrypted data
return util.ByteToHex(cipherText), nil
}
// AesCfbDecrypt will decrypt using aes cfb 256 bit,
// passphrase must be 32 bytes, if over 32 bytes, it be truncated
func AesCfbDecrypt(data string, passphrase string) (string, error) {
// ensure data has value
if len(data) == 0 {
return "", errors.New("Data to Decrypt is Required")
}
// ensure passphrase is 32 bytes
if len(passphrase) < 32 {
return "", errors.New("Passphrase Must Be 32 Bytes")
}
// cut the passphrase to 32 bytes only
passphrase = util.Left(passphrase, 32)
// convert data and passphrase into byte array
text, err := util.HexToByte(data)
if err != nil {
return "", err
}
key := []byte(passphrase)
// create aes cipher
c, err1 := aes.NewCipher(key)
// on error stop
if err1 != nil {
return "", err1
}
// ensure cipher block size appropriate
if len(text) < aes.BlockSize {
return "", errors.New("Cipher Text Block Size Too Short")
}
// iv needs to be unique, doesn't have to secured,
// it's common to put iv at the beginning of the cipher text
iv := text[:aes.BlockSize]
text = text[aes.BlockSize:]
// decrypt
stream := cipher.NewCFBDecrypter(c, iv)
// XORKeyStream can work in-place if two arguments are the same
stream.XORKeyStream(text, text)
// return decrypted data
return string(text), nil
}
// ================================================================================================================
// AES-CBC HELPERS
// ================================================================================================================
// AesCbcEncrypt will encrypt using aes cbc 256 bit,
// passphrase must be 32 bytes, if over 32 bytes, it be truncated,
// encrypted data is represented in hex value
func AesCbcEncrypt(data string, passphrase string) (string, error) {
// ensure data has value
if len(data) == 0 {
return "", errors.New("Data to Encrypt is Required")
}
// ensure passphrase is 32 bytes
if len(passphrase) < 32 {
return "", errors.New("Passphrase Must Be 32 Bytes")
}
// cut the passphrase to 32 bytes only
passphrase = util.Left(passphrase, 32)
// in cbc, data must be in block size of aes (multiples of 16 bytes),
// otherwise padding needs to be performed
if len(data)%aes.BlockSize != 0 {
// pad with blank spaces up to 16 bytes
data = util.Padding(data, util.NextFixedLength(data, aes.BlockSize), true, ascii.AsciiToString(ascii.NUL))
}
// convert data and passphrase into byte array
text := []byte(data)
key := []byte(passphrase)
// generate a new aes cipher using the 32 bytes key
c, err1 := aes.NewCipher(key)
// on error stop
if err1 != nil {
return "", err1
}
// iv needs to be unique, but doesn't have to be secure,
// its common to put it at the beginning of the cipher text
cipherText := make([]byte, aes.BlockSize+len(text))
// create iv, length must be equal to block size
iv := cipherText[:aes.BlockSize]
if _, err2 := io.ReadFull(rand.Reader, iv); err2 != nil {
return "", err2
}
// encrypt
mode := cipher.NewCBCEncrypter(c, iv)
mode.CryptBlocks(cipherText[aes.BlockSize:], text)
// return encrypted data
return util.ByteToHex(cipherText), nil
}
// AesCbcDecrypt will decrypt using aes cbc 256 bit,
// passphrase must be 32 bytes, if over 32 bytes, it be truncated
func AesCbcDecrypt(data string, passphrase string) (string, error) {
// ensure data has value
if len(data) == 0 {
return "", errors.New("Data to Decrypt is Required")
}
// ensure passphrase is 32 bytes
if len(passphrase) < 32 {
return "", errors.New("Passphrase Must Be 32 Bytes")
}
// cut the passphrase to 32 bytes only
passphrase = util.Left(passphrase, 32)
// convert data and passphrase into byte array
text, err := util.HexToByte(data)
if err != nil {
return "", err
}
key := []byte(passphrase)
// create aes cipher
c, err1 := aes.NewCipher(key)
// on error stop
if err1 != nil {
return "", err1
}
// ensure cipher block size appropriate
if len(text) < aes.BlockSize {
return "", errors.New("Cipher Text Block Size Too Short")
}
// iv needs to be unique, doesn't have to secured,
// it's common to put iv at the beginning of the cipher text
iv := text[:aes.BlockSize]
text = text[aes.BlockSize:]
// cbc mode always work in whole blocks
if len(text)%aes.BlockSize != 0 {
return "", errors.New("Cipher Text Must Be In Multiple of Block Size")
}
// decrypt
mode := cipher.NewCBCDecrypter(c, iv)
mode.CryptBlocks(text, text)
// return decrypted data
return strings.ReplaceAll(string(text[:]), ascii.AsciiToString(ascii.NUL), ""), nil
}
// ================================================================================================================
// HMAC HELPERS
// ================================================================================================================
// AppendHmac will calculate the hmac for the given encrypted data based on the given key,
// and append the Hmac to the end of the encrypted data and return the newly assembled encrypted data with hmac
// key must be 32 bytes
func AppendHmac(encryptedData string, key string) (string, error) {
// ensure data has value
if len(encryptedData) == 0 {
return "", errors.New("Data is Required")
}
// ensure key is 32 bytes
if len(key) < 32 {
return "", errors.New("Key Must Be 32 Bytes")
}
data := []byte(encryptedData)
// cut the key to 32 bytes only
key = util.Left(key, 32)
// new hmac
macProducer := hmac.New(sha256.New, []byte(key))
macProducer.Write(data)
// generate mac
strMac := util.ByteToHex(macProducer.Sum(nil))
mac := []byte(strMac)
// append and return
return string(append(data, mac...)), nil
}
// ValidateHmac will verify if the appended hmac validates against the message based on the given key,
// and parse the hmac out and return the actual message if hmac validation succeeds,
// if hmac validation fails, then blank is returned and the error contains the failure reason
func ValidateHmac(encryptedDataWithHmac string, key string) (string, error) {
// ensure data has value
if len(encryptedDataWithHmac) <= 64 { // hex is 2x the byte, so 32 normally is now 64
return "", errors.New("Data with HMAC is Required")
}
// ensure key is 32 bytes
if len(key) < 32 {
return "", errors.New("Key Must Be 32 Bytes")
}
// cut the key to 32 bytes only
key = util.Left(key, 32)
// data to byte
data := []byte(encryptedDataWithHmac)
// parse message
message := data[:len(data)-64]
mac, err := util.HexToByte(string(data[len(data)-64:]))
if err != nil {
return "", err
}
// new mac
macProducer := hmac.New(sha256.New, []byte(key))
macProducer.Write(message)
// get calculated mac
calculatedMac := macProducer.Sum(nil)
if hmac.Equal(mac, calculatedMac) {
// hmac match, return encrypted data without hmac
return string(message), nil
}
// if process gets here, then hmac failed
return "", errors.New("HMAC Verification Failed")
}
// ================================================================================================================
// RSA HELPERS
// ================================================================================================================
// RsaCreateKey generates the private and public key pair,
// expressed in hex code value
func RsaCreateKey() (privateKey string, publicKey string, err error) {
// generate new private key
rsaKey, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
return "", "", err
}
// get the public key
rsaPublicKey := &rsaKey.PublicKey
// get private key in bytes
bytesPrivateKey := pem.EncodeToMemory(&pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: x509.MarshalPKCS1PrivateKey(rsaKey)})
// get public key in bytes
bytesPublicKey := pem.EncodeToMemory(&pem.Block{
Type: "RSA PUBLIC KEY",
Bytes: x509.MarshalPKCS1PublicKey(rsaPublicKey)})
// return result
return util.ByteToHex(bytesPrivateKey), util.ByteToHex(bytesPublicKey), nil
}
// rsaPrivateKeyFromHex converts hex string private key into rsa private key object
func rsaPrivateKeyFromHex(privateKeyHex string) (*rsa.PrivateKey, error) {
// convert hex to bytes
bytesPrivateKey, err := util.HexToByte(privateKeyHex)
if err != nil {
return nil, err
}
// convert byte to object
block, _ := pem.Decode(bytesPrivateKey)
if block == nil {
return nil, errors.New("RSA Private Key From Hex Fail: " + "Pem Block Nil")
}
enc := x509.IsEncryptedPEMBlock(block)
b := block.Bytes
if enc {
b, err = x509.DecryptPEMBlock(block, nil)
if err != nil {
return nil, err
}
}
// parse key
key, err1 := x509.ParsePKCS1PrivateKey(b)
if err1 != nil {
return nil, err1
}
// return private key
return key, nil
}
// rsaPrivateKeyFromPem converts pkcs1 string private key into rsa private key object
func rsaPrivateKeyFromPem(privateKeyPem string) (*rsa.PrivateKey, error) {
block, _ := pem.Decode([]byte(privateKeyPem))
if block == nil {
return nil, errors.New("RSA Private Key From Pem Fail: " + "Pem Block Nil")
}
if key, err := x509.ParsePKCS1PrivateKey(block.Bytes); err != nil {
return nil, err
} else {
return key, nil
}
}
// rsaPublicKeyFromHex converts hex string public key into rsa public key object
func rsaPublicKeyFromHex(publicKeyHex string) (*rsa.PublicKey, error) {
// convert hex to bytes
bytesPublicKey, err := util.HexToByte(publicKeyHex)
if err != nil {
return nil, err
}
// convert byte to object
block, _ := pem.Decode(bytesPublicKey)
if block == nil {
return nil, errors.New("RSA Public Key From Hex Fail: " + "Pem Block Nil")
}
enc := x509.IsEncryptedPEMBlock(block)
b := block.Bytes
if enc {
b, err = x509.DecryptPEMBlock(block, nil)
if err != nil {
return nil, err
}
}
// parse key
key, err1 := x509.ParsePKCS1PublicKey(b)
if err1 != nil {
return nil, err1
}
// return public key
return key, nil
}
// rsaPublicKeyFromPem converts certificate string public key into rsa public key object
func rsaPublicKeyFromPem(publicKeyPem string) (*rsa.PublicKey, error) {
block, _ := pem.Decode([]byte(publicKeyPem))
if block == nil {
return nil, errors.New("RSA Public Key From Pem Fail: " + "Pem Block Nil")
}
if key, err := x509.ParsePKIXPublicKey(block.Bytes); err != nil {
return nil, err
} else {
return key.(*rsa.PublicKey), nil
}
}
// RsaPublicKeyEncrypt will encrypt given data using rsa public key,
// encrypted data is represented in hex value
//
// publicKeyHexOrPem = can be either HEX or PEM
func RsaPublicKeyEncrypt(data string, publicKeyHexOrPem string) (string, error) {
// data must not exceed 214 bytes
if len(data) > 214 {
return "", errors.New("RSA Public Key Encrypt Data Must Not Exceed 214 Bytes")
}
if len(data) == 0 {
return "", errors.New("Data To Encrypt is Required")
}
// get public key
var publicKey *rsa.PublicKey
var err error
if util.Left(publicKeyHexOrPem, 26) == "-----BEGIN PUBLIC KEY-----" && util.Right(publicKeyHexOrPem, 24) == "-----END PUBLIC KEY-----" {
// get public key from pem
publicKey, err = rsaPublicKeyFromPem(publicKeyHexOrPem)
} else {
// get public key from hex
publicKey, err = rsaPublicKeyFromHex(publicKeyHexOrPem)
}
if err != nil {
return "", err
}
// convert data into byte array
msg := []byte(data)
// create hash
hash := sha256.New()
// encrypt
cipherText, err1 := rsa.EncryptOAEP(hash, rand.Reader, publicKey, msg, nil)
if err1 != nil {
return "", err1
}
// return encrypted value
return util.ByteToHex(cipherText), nil
}
// RsaPrivateKeyDecrypt will decrypt rsa public key encrypted data using its corresponding rsa private key
//
// privateKeyHexOrPem = can be either HEX or PEM
func RsaPrivateKeyDecrypt(data string, privateKeyHexOrPem string) (string, error) {
// data to decrypt must exist
if len(data) == 0 {
return "", errors.New("Data To Decrypt is Required")
}
// get private key
var privateKey *rsa.PrivateKey
var err error
if util.Left(privateKeyHexOrPem, 27) == "-----BEGIN PRIVATE KEY-----" && util.Right(privateKeyHexOrPem, 25) == "-----END PRIVATE KEY-----" {
// get private key from pem text
privateKey, err = rsaPrivateKeyFromPem(privateKeyHexOrPem)
} else {
// get private key from hex
privateKey, err = rsaPrivateKeyFromHex(privateKeyHexOrPem)
}
if err != nil {
return "", err
}
// convert hex data into byte array
msg, err1 := util.HexToByte(data)
if err1 != nil {
return "", err1
}
// create hash
hash := sha256.New()
// decrypt
plainText, err2 := rsa.DecryptOAEP(hash, rand.Reader, privateKey, msg, nil)
if err2 != nil {
return "", err2
}
// return decrypted value
return string(plainText), nil
}
// RsaPrivateKeySign will sign the plaintext data using the given private key,
// NOTE: data must be plain text before encryption as signature verification is against plain text data
// signature is returned via hex
//
// privateKeyHexOrPem = can be either HEX or PEM
func RsaPrivateKeySign(data string, privateKeyHexOrPem string) (string, error) {
// data is required
if len(data) == 0 {
return "", errors.New("Data To Sign is Required")
}
// get private key
var privateKey *rsa.PrivateKey
var err error
if util.Left(privateKeyHexOrPem, 27) == "-----BEGIN PRIVATE KEY-----" && util.Right(privateKeyHexOrPem, 25) == "-----END PRIVATE KEY-----" {
// get private key from pem text
privateKey, err = rsaPrivateKeyFromPem(privateKeyHexOrPem)
} else {
privateKey, err = rsaPrivateKeyFromHex(privateKeyHexOrPem)
}
if err != nil {
return "", err
}
// convert data to byte array
msg := []byte(data)
// define hash
h := sha256.New()
h.Write(msg)
d := h.Sum(nil)
signature, err1 := rsa.SignPKCS1v15(rand.Reader, privateKey, crypto.SHA256, d)
if err1 != nil {
return "", err1
}
// return signature
return util.ByteToHex(signature), nil
}
// RsaPublicKeyVerify will verify the plaintext data using the given public key,
// NOTE: data must be plain text before encryption as signature verification is against plain text data
// if verification is successful, nil is returned, otherwise error is returned
//
// publicKeyHexOrPem = can be either HEX or PEM
func RsaPublicKeyVerify(data string, publicKeyHexOrPem string, signatureHex string) error {
// data is required
if len(data) == 0 {
return errors.New("Data To Verify is Required")
}
// get public key
var publicKey *rsa.PublicKey
var err error
if util.Left(publicKeyHexOrPem, 26) == "-----BEGIN PUBLIC KEY-----" && util.Right(publicKeyHexOrPem, 24) == "-----END PUBLIC KEY-----" {
// get public key from pem
publicKey, err = rsaPublicKeyFromPem(publicKeyHexOrPem)
} else {
// get public key from hex
publicKey, err = rsaPublicKeyFromHex(publicKeyHexOrPem)
}
if err != nil {
return err
}
// convert data to byte array
msg := []byte(data)
// define hash
h := sha256.New()
h.Write(msg)
d := h.Sum(nil)
sig, _ := util.HexToByte(signatureHex)
err1 := rsa.VerifyPKCS1v15(publicKey, crypto.SHA256, d, sig)
if err1 != nil {
return err1
}
// verified
return nil
}
// RsaPublicKeyEncryptAndPrivateKeySign will encrypt given data using recipient's rsa public key,
// and then using sender's rsa private key to sign,
// NOTE: data represents the plaintext data,
// encrypted data and signature are represented in hex values
//
// recipientPublicKeyHexOrPem = can be either HEX or PEM
// senderPrivateKeyHexOrPem = can be either HEX or PEM
func RsaPublicKeyEncryptAndPrivateKeySign(data string, recipientPublicKeyHexOrPem string, senderPrivateKeyHexOrPem string) (encryptedData string, signature string, err error) {
encryptedData, err = RsaPublicKeyEncrypt(data, recipientPublicKeyHexOrPem)
if err != nil {
encryptedData = ""
return "", "", err
}
signature, err = RsaPrivateKeySign(data, senderPrivateKeyHexOrPem)
if err != nil {
encryptedData = ""
signature = ""
return "", "", err
}
// return success values
return encryptedData, signature, nil
}
// RsaPrivateKeyDecryptAndPublicKeyVerify will decrypt given data using recipient's rsa private key,
// and then using sender's rsa public key to verify if the signature given is a match,
// NOTE: data represents the encrypted data
//
// recipientPrivateKeyHexOrPem = can be either HEX or PEM
// senderPublicKeyHexOrPem = can be either HEX or PEM
func RsaPrivateKeyDecryptAndPublicKeyVerify(data string, recipientPrivateKeyHexOrPem string, signatureHex string, senderPublicKeyHexOrPem string) (plaintext string, verified bool, err error) {
plaintext, err = RsaPrivateKeyDecrypt(data, recipientPrivateKeyHexOrPem)
if err != nil {
plaintext = ""
return "", false, err
}
err = RsaPublicKeyVerify(plaintext, senderPublicKeyHexOrPem, signatureHex)
if err != nil {
plaintext = ""
verified = false
return "", false, err
}
// return success values
return plaintext, true, nil
}
// ================================================================================================================
// RSA+AES DYNAMIC ENCRYPT/DECRYPT HELPERS
// ================================================================================================================
// RsaAesPublicKeyEncryptAndSign is a simplified wrapper method to generate a random AES key, then encrypt plainText using AES GCM,
// and then sign plain text data using sender's private key,
// and then using recipient's public key to encrypt the dynamic aes key,
// and finally compose the encrypted payload that encapsulates a full envelop:
// <STX>RsaPublicKeyEncryptedAESKeyData + AesGcmEncryptedPayload(PlainTextData<VT>SenderPublicKey<VT>PlainTextDataSignature)<ETX>
//
// warning: VT is used in encrypted payload as separator, make sure to escape VT if it is to be used inside the plainTextData <<< IMPORTANT
//
// recipientPublicKeyHexOrPem = can be either HEX or PEM
// senderPublicKeyHexOrPem = can be either HEX or PEM
// senderPrivateKeyHexOrPem = can be either HEX or PEM
func RsaAesPublicKeyEncryptAndSign(plainText string, recipientPublicKeyHexOrPem string, senderPublicKeyHexOrPem string, senderPrivateKeyHexOrPem string) (encryptedData string, err error) {
// validate inputs
if util.LenTrim(plainText) == 0 {
return "", errors.New("Data To Encrypt is Required")
}
if util.LenTrim(recipientPublicKeyHexOrPem) == 0 {
return "", errors.New("Recipient Public Key is Required")
}
if util.LenTrim(senderPublicKeyHexOrPem) == 0 {
return "", errors.New("Sender Public Key is Required")
}
if util.LenTrim(senderPrivateKeyHexOrPem) == 0 {
return "", errors.New("Sender Private Key is Required")
}
//
// generate random aes key for data encryption during this session
//
aesKey, err1 := Generate32ByteRandomKey(Sha256(util.NewUUID(), util.CurrentDateTime()))
if err1 != nil {
return "", errors.New("Dynamic AES New Key Error: " + err1.Error())
}
//
// rsa sender private key sign plain text data
//
signature, err2 := RsaPrivateKeySign(plainText, senderPrivateKeyHexOrPem)
if err2 != nil {
return "", errors.New("Dynamic AES Siganture Error: " + err2.Error())
}
//
// encrypt plain text data using aes key with aes gcm,
// note: payload format = plainText<VT>senderPublicKeyHex<VT>plainTextSignature
//
aesEncryptedData, err3 := AesGcmEncrypt(plainText+ascii.AsciiToString(ascii.VT)+senderPublicKeyHexOrPem+ascii.AsciiToString(ascii.VT)+signature, aesKey)
if err3 != nil {
return "", errors.New("Dynamic AES Data Encrypt Error: " + err3.Error())
}
//
// now protect the aesKey with recipient's public key using rsa encrypt
//
aesEncryptedKey, err4 := RsaPublicKeyEncrypt(aesKey, recipientPublicKeyHexOrPem)
if err4 != nil {
return "", errors.New("Dynamic AES Key Encrypt Error: " + err4.Error())
}
//
// compose output encrypted payload
// note: aesEncryptedKey_512_Bytes_Always + aesEncryptedData_Variable_Bytes + 64BytesRecipientPublicKeyHashWithSalt of 'TPK@2019' (TPK@2019 doesn't represent anything, just for backward compatibility in prior encrypted data)
// parse first 512 bytes of payload = aes encrypted key (use recipient rsa private key to decrypt)