How to create a RSA public key from a unsigned char * modulus and exponent 65537(RSA_F4)
Date : March 29 2020, 07:55 AM
Does that help I'm trying generate a rsa public key from a modulus type char[], and I now the exponent is RSA_F4(65537); But when I'm trying generate my public key using this values for "n" and "e", the RSA_public_encrypt, return 1; , You probably want something that looks more like: RSA *pubkey = RSA_new();
int len = BN_hex2bn(&pubkey>n, (const char *)p);
if (len == 0  p[len])
fprintf(stderr, "'%s' does not appear to be a valid modulus\n", p);
BN_hex2bn(&pubkey>e, "010001");
if (RSA_public_encrypt(....) <= 0)

Extracting modulus and exponent from public key using Openssl and C++
Tag : cpp , By : mikhaelrasputin
Date : March 29 2020, 07:55 AM
seems to work fine So I'm currently studying how networking works. I've got a bunch of packets from wireshark which I have already copied in buffers(only the content, without header. Wireshark>Follow TPC Stream>C arrays). I can understand the protocol but in the 3rd packet it requires a key exchange. After some googling I found that I need RSA encryption. It sends me a public key + token. And I shoud return encrypted shared key(just generated) and encrypted token which I received earlier. , The data you posted is an ASN.1 encoded (DER) RSA public key: $ openssl ssl rsa inform der pubin text < 12120862.key
PublicKey: (1024 bit)
Modulus:
00:81:1f:1d:00:7e:d0:c7:e2:2f:31:3d:0d:f0:a8:
ab:c1:ea:66:ba:af:1d:a4:eb:b3:fd:51:58:1c:1d:
81:ae:f0:99:9e:5c:26:67:b5:41:14:28:79:c0:29:
e5:56:96:06:b7:4b:a0:c9:7f:41:46:9a:7e:85:10:
a0:91:ea:58:bd:78:78:6d:3c:07:2a:3d:61:f3:ed:
42:8b:1e:dc:6d:2d:21:41:7a:e8:15:51:0d:75:84:
be:20:8c:76:43:8b:4b:67:6b:49:09:e9:20:a1:11:
53:a0:d9:30:b1:c2:27:a6:09:e1:56:36:ed:7e:9b:
23:e2:df:5b:bd:c5:66:ca:c5
Exponent: 65537 (0x10001)
writing RSA key
BEGIN PUBLIC KEY
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCBHx0AftDH4i8xPQ3wqKvB6ma6
rx2k67P9UVgcHYGu8JmeXCZntUEUKHnAKeVWlga3S6DJf0FGmn6FEKCR6li9eHht
PAcqPWHz7UKLHtxtLSFBeugVUQ11hL4gjHZDi0tna0kJ6SChEVOg2TCxwiemCeFW
Nu1+myPi31u9xWbKxQIDAQAB
END PUBLIC KEY

Generating an RSA KeyPair and extracting modulus and exponent from Public Key in Android
Date : March 29 2020, 07:55 AM
This might help you There was no native Android method to solve my problem. In order to extract the modulus and exponent of the generated Public Key, I used the following code, which takes an Android Public Key as Input and returns it in the .NET XML Format: public static String getPublicKeyAsXml(PublicKey publicKey) throws Exception
{
KeyFactory kf = KeyFactory.getInstance("RSA");
RSAPublicKeySpec ks = kf.getKeySpec(publicKey, RSAPublicKeySpec.class);
BigInteger modulus = ks.getModulus();
BigInteger exponent = ks.getPublicExponent();
byte[] modByte = modulus.toByteArray();
byte[] expByte = exponent.toByteArray();
modByte = testBytes(modByte);
expByte = testBytes(expByte);
String encodedModulus = Base64.encodeToString(modByte, Base64.NO_WRAP);
String encodedExponent = Base64.encodeToString(expByte, Base64.NO_WRAP);
String publicKeyAsXML = "<RSAKeyValue>" +
"<Modulus>" + encodedModulus + "</Modulus>" +
"<Exponent>" + encodedExponent + "</Exponent>" +
"</RSAKeyValue>";
return publicKeyAsXML;
}

Extract modulus n, private exponent and public exponent in Python cryptography library
Date : March 29 2020, 07:55 AM
I wish this help you I am using Python cryptography library and I need to encrypt something with RSA. It all works great, except one thing. , You can access using public_numbers() and private_numbers() public_key.public_numbers()
private_key.private_numbers()
In [13]: [a for a in dir(public_key) if not a.startswith("_")]
Out[13]: ['encrypt', 'key_size', 'public_bytes', 'public_numbers', 'verifier']
In [14]: [a for a in dir(private_key) if not a.startswith("_")]
Out[14]:
['decrypt',
'key_size',
'private_bytes',
'private_numbers',
'public_key',
'signer']
In [15]: [a for a in dir(private_key.private_numbers()) if not a.startswith("_")]
Out[15]: ['d', 'dmp1', 'dmq1', 'iqmp', 'p', 'private_key', 'public_numbers', 'q']
In [16]: [a for a in dir(public_key.public_numbers()) if not a.startswith("_")]
Out[16]: ['e', 'n', 'public_key']
In [17]: [a for a in dir(private_key.private_numbers().public_numbers) if not a.startswith("_")]
Out[17]: ['e', 'n', 'public_key']

How to store modulus, public exponent and private exponent securely on Android?
Date : March 29 2020, 07:55 AM

