iphone加密算法AES

NSData+AESTest.h 代码：

@interface NSData (AESTest)
- (NSData*)AES256EncryptWithKey:(NSString*)key;
- (NSData*)AES256DecryptWithKey:(NSString*)key;
@end

NSData+AESTest.m 代码：

#import <CommonCrypto/CommonCryptor.h
#import "NSData+ AESTest.h"
 @implementation NSData (AESAdditions)
- (NSData*)AES256EncryptWithKey:(NSString*)key {
    // 'key' should be 32 bytes for AES256, will be null-padded otherwise
    char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused)
    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
 
    // fetch key data
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
 
    NSUInteger dataLength = [self length];
 
    //See the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That's why we need to add the size of one block here
    size_t bufferSize           = dataLength + kCCBlockSizeAES128;
    void* buffer                = malloc(bufferSize);
 
    size_t numBytesEncrypted    = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                          keyPtr, kCCKeySizeAES256,
                                          NULL /* initialization vector (optional) */,
                                          [self bytes], dataLength, /* input */
                                          buffer, bufferSize, /* output */
                                          &numBytesEncrypted);
 
    if (cryptStatus == kCCSuccess)
    {
        //the returned NSData takes ownership of the buffer and will free it on deallocation
        return [NSMutableData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }
 
    free(buffer); //free the buffer;
    return nil;
}

- (NSData*)AES256DecryptWithKey:(NSString*)key {
    // 'key' should be 32 bytes for AES256, will be null-padded otherwise
    char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused)
    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
 
    // fetch key data
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
 
    NSUInteger dataLength = [self length];
 
    //See the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That's why we need to add the size of one block here
    size_t bufferSize           = dataLength + kCCBlockSizeAES128;
    void* buffer                = malloc(bufferSize);
 
    size_t numBytesDecrypted    = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                          keyPtr, kCCKeySizeAES256,
                                          NULL /* initialization vector (optional) */,
                                          [self bytes], dataLength, /* input */
                                          buffer, bufferSize, /* output */
                                          &numBytesDecrypted);
 
    if (cryptStatus == kCCSuccess)
    {
        //the returned NSData takes ownership of the buffer and will free it on deallocation
        return [NSMutableData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }
 
    free(buffer); //free the buffer;
    return nil;
}
@end

测试代码

#import "NSData+ AESTest.h"

int main (int argc, const char * argv[]) {
        NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

        NSString *key = @"my password";
        NSString *secret = @"text to encrypt";

        NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];
        NSData *cipher = [plain AES256EncryptWithKey:key];
        printf("%s/n", [[cipher description] UTF8String]);

        plain = [cipher AES256DecryptWithKey:key];
        printf("%s/n", [[plain description] UTF8String]);
        printf("%s/n", [[[NSString alloc] initWithData:plain encoding:NSUTF8StringEncoding] UTF8String]);

        [pool drain];
        return 0;
}

- (NSData*) encryptString:(NSString*)plaintext withKey:(NSString*)key {
        return [[plaintext dataUsingEncoding:NSUTF8StringEncoding] AES256EncryptWithKey:key];
}

- (NSString*) decryptData:(NSData*)ciphertext withKey:(NSString*)key {
        return [[[NSString alloc] initWithData:[ciphertext AES256DecryptWithKey:key]
                                      encoding:NSUTF8StringEncoding] autorelease];
}