QCA

rsatest.cpp
1 /*
2  Copyright (C) 2003 Justin Karneges <[email protected]>
3  Copyright (C) 2005 Brad Hards <[email protected]>
4 
5  Permission is hereby granted, free of charge, to any person obtaining a copy
6  of this software and associated documentation files (the "Software"), to deal
7  in the Software without restriction, including without limitation the rights
8  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9  copies of the Software, and to permit persons to whom the Software is
10  furnished to do so, subject to the following conditions:
11 
12  The above copyright notice and this permission notice shall be included in
13  all copies or substantial portions of the Software.
14 
15  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18  AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
19  AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
20  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 */
22 
23 #include <QCoreApplication>
24 #include <QtCrypto>
25 
26 #include <iostream>
27 
28 #ifdef QT_STATICPLUGIN
29 #include "import_plugins.h"
30 #endif
31 
32 int main(int argc, char **argv)
33 {
34  // The Initializer object sets things up, and also
35  // does cleanup when it goes out of scope
37 
38  QCoreApplication app(argc, argv);
39 
40  // we use the first argument if provided, or
41  // use "hello" if no arguments
42  QCA::SecureArray arg = (argc >= 2) ? argv[1] : "hello";
43 
44  // We demonstrate PEM usage here, so we need to test for
45  // supportedIOTypes, not just supportedTypes
46  if (!QCA::isSupported("pkey") || !QCA::PKey::supportedIOTypes().contains(QCA::PKey::RSA))
47  std::cout << "RSA not supported!\n";
48  else {
49  // When creating a public / private key pair, you make the
50  // private key, and then extract the public key component from it
51  // Using RSA is very common, however DSA can provide equivalent
52  // signature/verification. This example applies to DSA to the
53  // extent that the operations work on that key type.
54 
55  // QCA provides KeyGenerator as a convenient source of new keys,
56  // however you could also import an existing key instead.
58  if (seckey.isNull()) {
59  std::cout << "Failed to make private RSA key" << std::endl;
60  return 1;
61  }
62 
63  QCA::PublicKey pubkey = seckey.toPublicKey();
64 
65  // check if the key can encrypt
66  if (!pubkey.canEncrypt()) {
67  std::cout << "Error: this kind of key cannot encrypt" << std::endl;
68  return 1;
69  }
70 
71  // encrypt some data - note that only the public key is required
72  // you must also choose the algorithm to be used
73  QCA::SecureArray result = pubkey.encrypt(arg, QCA::EME_PKCS1_OAEP);
74  if (result.isEmpty()) {
75  std::cout << "Error encrypting" << std::endl;
76  return 1;
77  }
78 
79  // output the encrypted data
80  QString rstr = QCA::arrayToHex(result.toByteArray());
81  std::cout << "\"" << arg.data() << "\" encrypted with RSA is \"";
82  std::cout << qPrintable(rstr) << "\"" << std::endl;
83 
84  // save the private key - in a real example, make sure this goes
85  // somewhere secure and has a good pass phrase
86  // You can use the same technique with the public key too.
87  QCA::SecureArray passPhrase = "pass phrase";
88  seckey.toPEMFile(QStringLiteral("keyprivate.pem"), passPhrase);
89 
90  // Read that key back in, checking if the read succeeded
91  QCA::ConvertResult conversionResult;
92  QCA::PrivateKey privateKey =
93  QCA::PrivateKey::fromPEMFile(QStringLiteral("keyprivate.pem"), passPhrase, &conversionResult);
94  if (!(QCA::ConvertGood == conversionResult)) {
95  std::cout << "Private key read failed" << std::endl;
96  }
97 
98  // now decrypt that encrypted data using the private key that
99  // we read in. The algorithm is the same.
100  QCA::SecureArray decrypt;
101  if (0 == privateKey.decrypt(result, &decrypt, QCA::EME_PKCS1_OAEP)) {
102  std::cout << "Error decrypting.\n";
103  return 1;
104  }
105 
106  // output the resulting decrypted string
107  std::cout << "\"" << qPrintable(rstr) << "\" decrypted with RSA is \"";
108  std::cout << decrypt.data() << "\"" << std::endl;
109 
110  // Some private keys can also be used for producing signatures
111  if (!privateKey.canSign()) {
112  std::cout << "Error: this kind of key cannot sign" << std::endl;
113  return 1;
114  }
115  privateKey.startSign(QCA::EMSA3_MD5);
116  privateKey.update(arg); // just reuse the same message
117  QByteArray argSig = privateKey.signature();
118 
119  // instead of using the startSign(), update(), signature() calls,
120  // you may be better doing the whole thing in one go, using the
121  // signMessage call. Of course you need the whole message in one
122  // hit, which may or may not be a problem
123 
124  // output the resulting signature
125  rstr = QCA::arrayToHex(argSig);
126  std::cout << "Signature for \"" << arg.data() << "\" using RSA, is ";
127  std::cout << "\"" << qPrintable(rstr) << "\"" << std::endl;
128 
129  // to check a signature, we must check that the key is
130  // appropriate
131  if (pubkey.canVerify()) {
132  pubkey.startVerify(QCA::EMSA3_MD5);
133  pubkey.update(arg);
134  if (pubkey.validSignature(argSig)) {
135  std::cout << "Signature is valid" << std::endl;
136  } else {
137  std::cout << "Bad signature" << std::endl;
138  }
139  }
140 
141  // We can also do the verification in a single step if we
142  // have all the message
143  if (pubkey.canVerify() && pubkey.verifyMessage(arg, argSig, QCA::EMSA3_MD5)) {
144  std::cout << "Signature is valid" << std::endl;
145  } else {
146  std::cout << "Signature could not be verified" << std::endl;
147  }
148  }
149 
150  return 0;
151 }
ConvertResult
Return value from a format conversion.
Generic private key.
PrivateKey createRSA(int bits, int exp=65537, const QString &provider=QString())
Generate an RSA key of the specified length.
void startVerify(SignatureAlgorithm alg, SignatureFormat format=DefaultFormat)
Initialise the signature verification process.
void update(const MemoryRegion &a)
Update the signature process.
Conversion succeeded, results should be valid.
bool canSign() const
Test if this key can be used for signing.
char * data()
Pointer to the data in the secure array.
bool canVerify() const
Test if the key can be used for verifying signatures.
QByteArray toByteArray() const
Copy the contents of the secure array out to a standard QByteArray.
QCA_EXPORT bool isSupported(const char *features, const QString &provider=QString())
Test if a capability (algorithm) is available.
void startSign(SignatureAlgorithm alg, SignatureFormat format=DefaultFormat)
Initialise the message signature process.
Optimal asymmetric encryption padding (PKCS#1, Version 2.0)
Definition: qca_publickey.h:57
QByteArray signature()
The resulting signature.
MD5, with EMSA3 (ie PKCS#1 Version 1.5) encoding (this is the usual RSA algorithm) ...
Definition: qca_publickey.h:78
bool decrypt(const SecureArray &in, SecureArray *out, EncryptionAlgorithm alg)
Decrypt the message.
bool toPEMFile(const QString &fileName, const SecureArray &passphrase=SecureArray(), PBEAlgorithm pbe=PBEDefault) const
Export the key in Privacy Enhanced Mail (PEM) format to a file.
QCA_EXPORT QString arrayToHex(const QByteArray &array)
Convert a byte array to printable hexadecimal representation.
QCA_EXPORT void init()
Initialise QCA.
bool isNull() const
Test if the key is null (empty)
bool verifyMessage(const MemoryRegion &a, const QByteArray &sig, SignatureAlgorithm alg, SignatureFormat format=DefaultFormat)
Single step message verification.
Secure array of bytes.
Definition: qca_tools.h:316
Class for generating asymmetric key pairs.
PublicKey toPublicKey() const
Interpret this key as a PublicKey.
bool validSignature(const QByteArray &sig)
Check the signature is valid for the message.
Convenience method for initialising and cleaning up QCA.
Definition: qca_core.h:659
bool isEmpty() const
Test if the array contains any bytes.
Generic public key.
static QList< Type > supportedIOTypes(const QString &provider=QString())
Test what types of keys are supported for IO operations.
static PrivateKey fromPEMFile(const QString &fileName, const SecureArray &passphrase=SecureArray(), ConvertResult *result=nullptr, const QString &provider=QString())
Import the key in Privacy Enhanced Mail (PEM) format from a file.
SecureArray encrypt(const SecureArray &a, EncryptionAlgorithm alg)
Encrypt a message using a specified algorithm.
void update(const MemoryRegion &a)
Update the signature verification process with more data.
bool canEncrypt() const
Test if this key can be used for encryption.
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