iOS开发之Objective-c的MD5/SHA1加密算法的实现

Objective-c实现MD5和SHA1算法相对还是比较简单的，可以直接调用系统的C/C++共享库来实现调用
MD5即Message Digest Algorithm 5（信息-摘要算法 5），用于确保信息传输完整一致。是计算机广泛使用的杂凑算法之一
SHA即Secure Hash Algorithm（安全散列算法) 是美国国家安全局 (NSA) 设计，美国国家标准与技术研究院 (NIST) 发布的一系列密码散列函数。


使用方式如下:
MD5加密方式

-(NSString *) md5
{
    const charchar *cStr = [self UTF8String];
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( cStr, strlen(cStr), digest );

    NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];

    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];

    return output;
}
SHA1加密方式
  - (NSString *) sha1:(NSString *)input{    const char *cstr = [input cStringUsingEncoding:NSUTF8StringEncoding];    NSData *data = [NSData dataWithBytes:cstr length:input.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;}
当然也可以结合BASE64来使用,这里的BASE64编码使用 GTMBase64实现，需要导入

- (NSString *) sha1_base64
{
    const charchar *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;
}

- (NSString *) md5_base64
{
    const charchar *cStr = [self UTF8String];
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( cStr, strlen(cStr), digest );

    NSData * base64 = [[NSData alloc]initWithBytes:digest length:CC_MD5_DIGEST_LENGTH];
    base64 = [GTMBase64 encodeData:base64];

    NSString * output = [[NSString alloc] initWithData:base64 encoding:NSUTF8StringEncoding];
    return output;
}
通过拓展NSString，实现完整功能，全部代码

@interface NSString (encrypto)
- (NSString *) md5;
- (NSString *) sha1;
- (NSString *) sha1_base64;
- (NSString *) md5_base64;
- (NSString *) base64;

@end
@implementation NSString (encrypto)
- (NSString*) sha1
{
    const charchar *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;
}

-(NSString *) md5
{
    const charchar *cStr = [self UTF8String];
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( cStr, strlen(cStr), digest );

    NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];

    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];

    return output;
}

- (NSString *) sha1_base64
{
    const charchar *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;
}

- (NSString *) md5_base64
{
    const charchar *cStr = [self UTF8String];
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( cStr, strlen(cStr), digest );

    NSData * base64 = [[NSData alloc]initWithBytes:digest length:CC_MD5_DIGEST_LENGTH];
    base64 = [GTMBase64 encodeData:base64];

    NSString * output = [[NSString alloc] initWithData:base64 encoding:NSUTF8StringEncoding];
    return output;
}

- (NSString *) base64
{
    NSData * data = [self dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
    data = [GTMBase64 encodeData:data];
    NSString * output = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    return output;
}
@end
实现时候不要忘记导入CC相关的库的头文件
CommonCrypto/CommonDigest.h