Convert NSData to String?

Question

I am storing a openssl private Key EVP_PKEY as nsdata. For this I am serializing into a byte stream using the code below

unsigned char *buf, *p;
int len;
len = i2d_PrivateKey(pkey, NULL);
buf = OPENSSL_malloc(len); 
p = buf;
i2d_PrivateKey(pkey, &p);

where pkey is of type EVP_PKEY. Then I am storing the bytes from buffer 'p' as an NSData using the line given below

NSData *keydata = [NSData dataWithBytes:P length:len];

Now I am converting it to a NSString using the code given below but when i print it into console its giving some other characters.

NSString *content =[ NSString stringWithCString:[keydata bytes] encoding:NSUTF8StringEncoding];

Could someone help?

Basically I want to store the EVP_PKEY into a sqlite database

am I on the right track? Thanks.

user_1446573 · Answer

Swift 3:

String(data: data, encoding: .utf8)

user_2789065 · Answer

A simple way to convert arbitrary NSData to NSString is to base64 encode it.

NSString *base64EncodedKey = [keydata base64EncodedStringWithOptions: NSDataBase64Encoding64CharacterLineLength];

You can then store it into your database for reuse later. Just decode it back to NSData.