【iOS】加密算法整理

1、MD5:

- (NSString *)getMd5_32Bit {
    const char *cStr = [self UTF8String];
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( cStr, strlen(cStr), digest);
    NSMutableString *result = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [result appendFormat:@"%02x", digest[i]];
    return result;
}

2、AED:

- (NSData *)AES256EncryptWithKey:(NSString *)key {
    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 {
    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, kCCOptionECBMode|kCCOptionPKCS7Padding, keyPtr, kCCBlockSizeAES128, NULL, [self bytes], dataLength, buffer, bufferSize, &numBytesDecrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }
    
    free(buffer);
    return nil;
}

3、DES

+ (NSString *)TripleDES:(NSString *)plainText encryptOrDecrypt:(CCOperation)encryptOrDecrypt
                withKey:(NSString *)DESKEY  {
    const void *vPlainText;
    size_t plainTextBufferSize;
    if (encryptOrDecrypt == kCCDecrypt) {
        NSData *EncryptData = [GTMBase64 decodeData:[plainText dataUsingEncoding:NSUTF8StringEncoding]];
        plainTextBufferSize = [EncryptData length];
        vPlainText = [EncryptData bytes];
    } else {
        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 moveBytes = 0;
    
    bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
    bufferPtr =  malloc(bufferPtrSize * sizeof(uint8_t));
    memset((void *)bufferPtr, 0x0, bufferPtrSize);
    
    const void *vkey = (const void *)[DESKEY UTF8String];
    ccStatus = CCCrypt(encryptOrDecrypt, kCCAlgorithm3DES, kCCOptionECBMode|kCCOptionPKCS7Padding, vkey, kCCKeySize3DES, nil, vPlainText, plainTextBufferSize, (void *)bufferPtr, bufferPtrSize, &moveBytes);
  
    NSString *result;
    if (encryptOrDecrypt == kCCDecrypt) {
        result = [[NSString alloc] initWithData:[NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)moveBytes] encoding:NSUTF8StringEncoding];
    } else {
        NSData *data = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger) moveBytes];
        result = [GTMBase64 stringByEncodingData:data];
    }
    
    return result;
}

注意引入头文件：#import <CommonCrypto/CommonCrypto.h>