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I have a windows application (Visual Studio is used) that uses Microsoft CryptoAPI. Now it is required to develop a Mac OS X application, that is capable to read data, encrypted by the WinApp, and encrypt data on Mac OS X, that will be decrypted by the WinApp. Encryption/decription in the WinApp initialized in the such way:

::CryptAcquireContext(&m_hCryptProv, NULL, MS_DEF_PROV, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
::CryptCreateHash(m_hCryptProv, CALG_MD5, 0, 0, &m_hCryptHash);
::CryptHashData(m_hCryptHash, pbtPSW, dwPSWLen, 0);
::CryptDeriveKey(m_hCryptProv, CALG_RC4, m_hCryptHash, 0, &m_hCryptKey);

And for encryption/decription the following is used:

::CryptEncrypt(m_hCryptKey, 0, TRUE, 0, pBuf, &dwCnt, dwLen);
::CryptDecrypt(m_hCryptKey, 0, TRUE, 0, pBuf, &dwCnt);

As I understand, I need to find a library that implements MD5 hashing plus RC4 encoding/decoding. It seems that there are a number of such libraries. For example: matrixSSL, OpenSSL. But using of the libraries for my puproses is not obvious (especially taking into account, that I am not familiar with Sequrity/Crypting APIs). Could somebody recommend a particular ciphering library? May be there are code examples for my task?

ADDITION:

It seems the main problem is that I need a portable analog of the ::CryptDeriveKey, that is compatible with Microsoft version (i.e. generates the same key). Does anybody know a such one? Or an algorithm of creating a key by the ::CryptDeriveKey?

pnuts
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VitalyVal
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  • Hmm, you are going to port cryptography-related code without even understanding what the source does. Doesn't make much sense from security point of view ... – Eugene Mayevski 'Callback Jan 27 '11 at 13:13
  • Eugene, what I would like to do - replace original CryptoAPI functions with analogs from a portable library. And it is desirable, that this job takes as small time as possible. This is not a sequrity critical application, and the encryption/decryption is simply a small and not very important part. – VitalyVal Jan 27 '11 at 13:51
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    it doesn't matter, hos important security is. You just won't make it right without understanding what you are doing. – Eugene Mayevski 'Callback Jan 27 '11 at 15:04

1 Answers1

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I would recommend taking a look at the CyaSSL embedded SSL library. It supports the current standards up to TLS 1.2 and is very portable across operating systems. In particular, CyaSSL includes the CTaoCrypt cryptographic library which should let you perform the crypto operations you're looking for.

Some helpful documentation links for CyaSSL:

CTaoCrypt Usage Reference: http://yassl.com/yaSSL/Docs_CTaoCrypt_Usage_Reference.html
CyaSSL Docs Page: http://yassl.com/yaSSL/Docs.html

If you download CyaSSL, you'll find a Visual Studio project file to take a look at as well.

Regards,
Chris

Chrisc
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  • Thanks Chris. As I wrote in addition to original message, the main problem is to implement ::CryptDeriveKey exactly in the same way as the ::CryptDeriveKey work. Because of weak original approach, a key is not stored togather with encrypted file. So I need to reproduce procedure of generating the key (particulary ::CryptDeriveKey function). – VitalyVal Jan 28 '11 at 21:26