Using PHP/Python to verify ECDSA signature - php

Question

I write the code to generate ECDSA signature on Android using spongycastle lib. Then I send the sign string and public-key to server (Ubuntu 16.04) and try to use php and python to verify this sign.
I test verify on my android app. It worked well.
I use php-openssl extension and with Python I use ecdsa 0.13. But, both of this failed. I try again, using openssl command and it can't verify too.
I don't know, where I am wrong.
Why is the ECDSA verification failing?
Here is my code:
Generate signature (android):
ECNamedCurveParameterSpec spec = ECNamedCurveTable.getParameterSpec("prime256v1");
try {
KeyPairGenerator g = KeyPairGenerator.getInstance("ECDSA","SC");
g.initialize(spec, new SecureRandom());
KeyPair keyPair = g.generateKeyPair();
privateKey = keyPair.getPrivate();
publicKey = keyPair.getPublic();
///write public key to pem file
......
FileOutputStream fileOutputStream1 = new FileOutputStream(file1);
StringWriter writer1 = new StringWriter();
PemWriter pemWriter1 = new PemWriter(writer1);
pemWriter1.writeObject(new PemObject("PUBLIC KEY",publicKey.getEncoded()));
pemWriter1.flush();
pemWriter1.close();
String publickeyPem = writer1.toString();
fileOutputStream1.write(publickeyPem.getBytes());
fileOutputStream1.close();
} catch (Exception e) {
e.printStackTrace();}
......
//Sign and veryfied
String chuoi = txtChuoi.getText().toString();
byte[] chuoiInput = chuoi.getBytes("UTF-8");
Signature sig = Signature.getInstance("NONEwithECDSA","SC");
sig.initSign(privateKey);
sig.update(chuoiInput);
///SIGN
byte[] signatureBytes = sig.sign()
txtMaHoa.setText(Base64.encodeToString(signatureBytes,Base64.DEFAULT));
sig.initVerify(publicKey);
sig.update(chuoiInput);
///VERIFIED
txtGiaiMa.setText(sig.verify(signatureBytes)+"");
///Write string sign in txtMahoa to file
.......
Output I have Signature and publickey are:
(Signature string) MEYCIQC7Hz631IFGsUOogcRLeN99uM9hWgLr+LGzuJvR/6nBrgIhAMXgZcvXyMRCAELXlNNS1a9j iAT1x0q2C5Mdu+2aZKtN
(Publickey)
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEj07XEM+ulPyrdsfAf9prN2L2dNUd /Yy0rABcFdueAwYUf86f8Cc93Ws6sxzIvf2iKOapFby7EjHewjhLM/z7Qg==
-----END PUBLIC KEY-----
Verify using PHP:
$pubkeyid = openssl_pkey_get_public("/var/www/html/ca.pem");
$data = "nguyen tran thanh Lam";
$signature =
"MEYCIQC7Hz631IFGsUOogcRLeN99uM9hWgLr+LGzuJvR/6nBrgIhAMXgZcvXyMRCAELXlNNS1a9jiAT1x0q2C5Mdu+2aZKtN";
$ok = openssl_verify($data, $signature, $pubkeyid);
if ($ok == 1) {
echo "good";
} elseif ($ok == 0) {
echo "bad";
} else {
echo "ugly, error checking signature";
}
?>

Answer 1

Comment: ... but the verify function don't return anything. So I not sure
If crypto.verify(... don't throw an Error, this means Verify is OK. See updated Code below.
Verify with using WRONG Certificat, Signature or Data.
Comment: what do you think about add base64.b64decode. ... because in android code I have this linetxtMaHoa.setText(Base64.encodeToString(signatureBytes,Ba‌​se64.DEFAULT));
PEM is already base64, check if the above .setText(Base64... can omitted. For now I have updated the Code below with base64.b64decode.
Question: Example ---- b"sha256"? "b" is a binary (built-in funtion or I must convert string sha256 to binary?)
Works for me only as String (digest-names), for example:
import pem, base64
from OpenSSL import crypto
signature = b"MEYCIQC7Hz631IFGsUOogcRLeN99uM9hWgLr+LGzuJvR/6nBrgIhAMXgZcvXyMRCAELXlNNS1a9jiAT1x0q2C5Mdu+2aZKtN"
# As Creator of the Signatur do additional base64 encoding!
signature = base64.b64decode(signature)
data = "nguyen tran thanh Lam"
certificate = pem.parse_file('Android.pem')[0]
cert = crypto.load_certificate(crypto.FILETYPE_PEM, certificate.as_bytes())
try:
crypto.verify(cert=cert, signature=signature, data=data, digest='sha256')
except crypto.Error as exp:
print('crypto.Error:{}'.format(exp.args))
>>>crypto.Error:([('', 'ECDSA_do_verify', 'bad signature')],)
Note: Throws crypto.Error because not using the certificate which created the signature.
OpenSSL.crypto.verify(certificate, signature, data, digest)
Verify the signature for a data string.
certificate is a X509 instance corresponding to the private key which generated the signature.
signature is a str instance giving the signature itself.
data is a str instance giving the data to which the signature applies.
digest is a str instance naming the message digest type of the signature, for example b"sha256".
New in version 0.11.