Add Decrypt function

[Sean-Wang]

很好用的一个 RSA 第三方库，希望能够加上解密的功能。

[btnguyen2k]

Swift implementation, also has decryption function: https://github.com/btnguyen2k/swift-rsautils

[ideawu]

@btnguyen2k Can you add Objective-C version descryption function to this project?

[btnguyen2k]

@ideawu I have created a pull request for decryption function.

[coskungun]

how to decryption private key ?

[btnguyen2k]

@coskungun, private key is a bit more complicated than I thought. I have add function to decrypt with private key in my Swift version: https://github.com/btnguyen2k/swift-rsautils

Still, encryption with private key has not worked yet. I will be investigating this a few more days and will update the ObjC code latter.

[ideawu]

Thanks to @btnguyen2k , we have more functions now:

+ (NSString *)decryptString:(NSString *)str publicKey:(NSString *)pubKey;
+ (NSData *)decryptData:(NSData *)data publicKey:(NSString *)pubKey;
+ (NSString *)decryptString:(NSString *)str privateKey:(NSString *)privKey;
+ (NSData *)decryptData:(NSData *)data privateKey:(NSString *)privKey;

[coskungun]

@btnguyen2k thank you very much. =)

[thidayatullah]

@ideawu : I want to do testing but when I try to decrypt using private_key it return nil.

specifically on the method : + (NSData *)stripPrivateKeyHeader:(NSData *)d_key the data is there (610 bytes long) but it returns nil after being stripped.

[stdawn]

ios9 真机调试下，RSA加密会随机失败，怎么解决，static public func encryptWithRSAPublicKey(data: NSData, pubkeyBase64: String, keychainTag: String) -> NSData? 方法随机返回 nil