Various encryption and decryption and codec for IOS development

Various encryption and decryption and codec for IOS development

1. AES encryption and decryption: Add NSData + AES to NSData

Add header file # import

-(NSData *) AES256EncryptWithKey :( NSString *) key {// Encryption

Char keyPtr [kCCKeySizeAES256 + 1];
Bzero (keyPtr, sizeof (keyPtr ));
[Key getCString: keyPtr maxLength: sizeof (keyPtr) encoding: NSUTF8StringEncoding];
NSUInteger dataLength = [self length];
Size_t bufferSize = dataLength + kCCBlockSizeAES128;
Void * buffer = malloc (bufferSize );
Size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt (kCCEncrypt, kCCAlgorithmAES128,
KCCOptionPKCS7Padding | kCCOptionECBMode,
KeyPtr, kCCBlockSizeAES128,
NULL,
[Self bytes], dataLength,
Buffer, bufferSize,
& NumBytesEncrypted );
If (cryptStatus = kCCSuccess ){
Return [NSData dataWithBytesNoCopy: buffer length: numBytesEncrypted];
}
Free (buffer );
Return nil;
}


-(NSData *) AES256DecryptWithKey :( NSString *) key {// decryption
Char keyPtr [kCCKeySizeAES256 + 1];
Bzero (keyPtr, sizeof (keyPtr ));
[Key getCString: keyPtr maxLength: sizeof (keyPtr) encoding: NSUTF8StringEncoding];
NSUInteger dataLength = [self length];
Size_t bufferSize = dataLength + kCCBlockSizeAES128;
Void * buffer = malloc (bufferSize );
Size_t numBytesDecrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt (kCCDecrypt, kCCAlgorithmAES128,
KCCOptionPKCS7Padding | kCCOptionECBMode,
KeyPtr, kCCBlockSizeAES128,
NULL,
[Self bytes], dataLength,
Buffer, bufferSize,
& NumBytesDecrypted );
If (cryptStatus = kCCSuccess ){
Return [NSData dataWithBytesNoCopy: buffer length: numBytesDecrypted];
}
Free (buffer );
Return nil;

}

 

2. base64 encoding/decoding reference

GTMDefines. h
GTMBase64.h
GTMBase64.m

 

3. Various encryption and digital summarization. Add category NSString + Encrypto to NSString

(1). MD5 digital digest

-(NSString *) md5 {

Const char * cStr = [self UTF8String];
Unsigned char result [16];
CC_MD5 (cStr, strlen (cStr), result );
Return [NSString stringWithFormat: @ % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X % 02X,
Result [0], result [1], result [2], result [3],
Result [4], result [5], result [6], result [7],
Result [8], result [9], result [10], result [11],
Result [12], result [13], result [14], result [15]
];
}

 

(2) SHA1 Abstract

 

- (NSString*) sha1{    const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];    NSData *data = [NSData dataWithBytes:cstr length:self.length];     uint8_t digest[CC_SHA1_DIGEST_LENGTH];     CC_SHA1(data.bytes, data.length, digest);     NSMutableString* output = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH * 2];     for(int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++)        [output appendFormat:@%02x, digest[i]];     return output;}

(3) base64 encoding

- (NSString *) base64{        NSData * data = [self dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];     data = [GTMBase64 encodeData:data];     NSString * output = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];     return output; }

(4) combination of SHA1 and base64

- (NSString *) sha1_base64{    const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];    NSData *data = [NSData dataWithBytes:cstr length:self.length];     uint8_t digest[CC_SHA1_DIGEST_LENGTH];     CC_SHA1(data.bytes, data.length, digest);     NSData * base64 = [[NSData alloc]initWithBytes:digest length:CC_SHA1_DIGEST_LENGTH];    base64 = [GTMBase64 encodeData:base64];     NSString * output = [[NSString alloc] initWithData:base64 encoding:NSUTF8StringEncoding];     return output; } 

(5) combination of MD5 and base64-(NSString *) md5_base64 {const char * cStr = [self UTF8String]; unsigned char digest [CC_MD5_DIGEST_LENGTH]; CC_MD5 (cStr, strlen (cStr ), digest); NSData * base64 = [[NSData alloc] initWithBytes: digest length: bytes]; base64 = [GTMBase64 encodeData: base64]; NSString * output = [[NSString alloc] initWithData: base64 encoding: NSUTF8StringEncoding]; return output ;}

 

4.3DES is a symmetric encryption method because the same key is used.

For information about encryption and decryption security, refer to google and baidu.

I am simply talking about a feasible solution in communication encryption.

The same 3DES encryption is basically uniform, and the system also provides APIs directly. The basic code is as follows:

// 3des encryption and decryption
+ (NSString *) TripleDES :( NSString *) plainText encryptOrDecrypt :( CCOperation) encryptOrDecrypt
{
Const void * vplainText;
Size_t plainTextBufferSize;

If (encryptOrDecrypt = kCCDecrypt) // decrypt
{
NSData * EncryptData = [GTMBase64 decodeData: [plainText dataUsingEncoding: NSUTF8StringEncoding];
PlainTextBufferSize = [EncryptData length];
VplainText = [EncryptData bytes];
}
Else // Encryption
{
NSData * data = [plainText dataUsingEncoding: NSUTF8StringEncoding];
PlainTextBufferSize = [data length];
VplainText = (const void *) [data bytes];
}

CCCryptorStatus ccStatus;
Uint8_t * bufferPtr = NULL;
Size_t bufferPtrSize = 0;
Size_t movedBytes = 0;

BufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES )&~ (KCCBlockSize3DES-1 );
BufferPtr = malloc (bufferPtrSize * sizeof (uint8_t ));
Memset (void *) bufferPtr, 0x0, bufferPtrSize );
// Memset (void *) iv, 0x0, (size_t) sizeof (iv ));

Const void * vkey = (const void *) [cipher ey UTF8String];
// NSString * initVec = @ init Vec;
// Const void * vinitVec = (const void *) [initVec UTF8String];
// Byte iv [] = {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
CcStatus = CCCrypt (encryptOrDecrypt,
KCCAlgorithm3DES,
KCCOptionPKCS7Padding | kCCOptionECBMode,
Vkey,
KCCKeySize3DES,
Nil,
VplainText,
PlainTextBufferSize,
(Void *) bufferPtr,
BufferPtrSize,
& MovedBytes );
// If (ccStatus = kCCSuccess) NSLog (@ SUCCESS );
/* Else if (ccStatus = kCC ParamError) return @ param error;
Else if (ccStatus = kCCBufferTooSmall) return @ buffer too small;
Else if (ccStatus = kCCMemoryFailure) return @ memory failure;
Else if (ccStatus = kCCAlignmentError) return @ ALIGNMENT;
Else if (ccStatus = kCCDecodeError) return @ decode error;
Else if (ccStatus = kCCUnimplemented) return @ UNIMPLEMENTED ;*/

NSString * result;

If (encryptOrDecrypt = kCCDecrypt)
{
Result = [[[NSString alloc] initWithData: [NSData dataWithBytes :( const void *) bufferPtr
Length :( NSUInteger) movedBytes]
Encoding: NSUTF8StringEncoding]
Autorelease];
}
Else
{
NSData * myData = [NSData dataWithBytes :( const void *) bufferPtr length :( NSUInteger) movedBytes];
Result = [GTMBase64 stringByEncodingData: myData];
}

Return result;
}