iOS AES加密解密实现方法

使用方法 先导入头文件 #import "NSData+AES.h"

//AES测试
//用来密钥
NSString *key = @"123456";
//用来发送的原始数据
NSString *secret = @"I Love You";
//数据转码
NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];
//用密钥加密
NSData *cipher = [plain AES256EncryptWithKey:key];

//输出测试
NSLog(@"%@",[cipher newStringInBase64FromData]);
printf("%s\n", [[cipher description] UTF8String]);
//打印出null,这是因为没有解密
NSLog(@"%@", [[NSString alloc] initWithData:cipher encoding:NSUTF8StringEncoding]);

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

自建NSData类别 命名AES

NSData+AES.h

#import <Foundation/Foundation.h>

@interface NSData (AES)

- (NSData *)AES256EncryptWithKey:(NSString *)key;   //加密

- (NSData *)AES256DecryptWithKey:(NSString *)key;   //解密

- (NSString *)newStringInBase64FromData;            //追加64编码

+ (NSString*)base64encode:(NSString*)str;           //同上64编码

@end

NSData+AES.m

#import "NSData+AES.h"
#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonCryptor.h>

static char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

@implementation NSData (AES)

- (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 [NSData 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 [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }

    free(buffer); //free the buffer;
    return nil;
}

- (NSString *)newStringInBase64FromData            //追加64编码
{
    NSMutableString *dest = [[NSMutableString alloc] initWithString:@""];
    unsigned char * working = (unsigned char *)[self bytes];
    int srcLen = [self length];
    for (int i=0; i<srcLen; i += 3) {
        for (int nib=0; nib<4; nib++) {
            int byt = (nib == 0)?0:nib-1;
            int ix = (nib+1)*2;
            if (i+byt >= srcLen) break;
            unsigned char curr = ((working[i+byt] << (8-ix)) & 0x3F);
            if (i+nib < srcLen) curr |= ((working[i+nib] >> ix) & 0x3F);
            [dest appendFormat:@"%c", base64[curr]];
        }
    }
    return dest;
}

+ (NSString*)base64encode:(NSString*)str
{
    if ([str length] == 0)
        return @"";
    const char *source = [str UTF8String];
    int strlength  = strlen(source);
    char *characters = malloc(((strlength + 2) / 3) * 4);
    if (characters == NULL)
        return nil;
    NSUInteger length = 0;
    NSUInteger i = 0;
    while (i < strlength) {
        char buffer[3] = {0,0,0};
        short bufferLength = 0;
        while (bufferLength < 3 && i < strlength)
            buffer[bufferLength++] = source[i++];
        characters[length++] = base64[(buffer[0] & 0xFC) >> 2];
        characters[length++] = base64[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];
        if (bufferLength > 1)
            characters[length++] = base64[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];
        else characters[length++] = ‘=‘;
        if (bufferLength > 2)
            characters[length++] = base64[buffer[2] & 0x3F];
        else characters[length++] = ‘=‘;
    }
    NSString *g = [[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES];
    return g;
}

@end