Uni/CSI-ES-2324
4
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

[PD1] decryptMessageContent implemented

Browse source 
needs testing
This commit is contained in:
Tiago Sousa 2024-04-19 19:52:23 +01:00
parent c131aa2aea
commit fb7a728aa4
Signed by: tiago
SSH key fingerprint: SHA256:odOD9vln9U7qNe1R8o3UCbE3jkQCkr5/q5mgd5hwua0
1 changed files with 31 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

24
Projs/PD1/internal/utils/cryptoUtils/cryptoUtils.go
View file

@ -179,8 +179,30 @@ func (k KeyStore) EncryptMessageContent(receiverCert *x509.Certificate, content
} }
func (k KeyStore) DecryptMessageContent(senderCert *x509.Certificate, cipherContent []byte) []byte { func (k KeyStore) DecryptMessageContent(senderCert *x509.Certificate, cipherContent []byte) []byte {
encryptedDataKey, encryptedMsg := unPair(cipherContent)
dataKey, err := rsa.DecryptOAEP(sha256.New(), rand.Reader, k.GetPrivKey(), encryptedDataKey, nil)
if err != nil {
log.Panicln("Could not decrypt dataKey: ", err)
}
// decrypt ciphertext
cipher, err := chacha20poly1305.New(dataKey)
if err != nil {
log.Panicln("Could not create cipher: ", err)
}
return nil nonce, ciphertext := encryptedMsg[:cipher.NonceSize()], encryptedMsg[cipher.NonceSize():]
contentAndSig, err := cipher.Open(nil, nonce, ciphertext, nil)
if err != nil {
log.Panicln("Could not decrypt ciphertext: ", err)
}
// check signature with sender public key
content, signature := unPair(contentAndSig)
hashedContent := sha256.Sum256(content)
senderKey := senderCert.PublicKey.(*rsa.PublicKey)
if err := rsa.VerifyPKCS1v15(senderKey, crypto.SHA256, hashedContent[:], signature); err != nil {
log.Panicln("Signature is not valid: ", err)
}
return content
} }
func pair(l []byte, r []byte) []byte { func pair(l []byte, r []byte) []byte {