iOS:Objective-c的MD5/SHA1加密算法的实现

介绍：

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。

链接：http://m.111cn.net/art-53370.htm

使用方式如下:
MD5加密方式

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

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

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

    return output;
}

SHA1加密方式

 - (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 * ];

    for(int i = ; 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

//结合base64的sha1加密
 - (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;
}

//结合base64的md5加密
- (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:CC_MD5_DIGEST_LENGTH];
    base64 = [GTMBase64 encodeData:base64];

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

例子一：通过类扩展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 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 * ];

    for(int i = ; i < CC_SHA1_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];

    return output;
}

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

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

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

    return output;
}

- (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;
}

- (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: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

注意：

1.实现时候不要忘记导入CC相关的库的头文件
CommonCrypto/CommonDigest.h

2.在实现时还需要依赖这三个文件：GTMBase64.h   GTMBase64.m   GTMDefines.h

这三个文件的链接：

第一个：http://code.google.com/p/google-toolbox-for-mac/source/browse/trunk/Foundation/?r=87

第二个：gtmbase64.zip

例子二：通过类扩展NSString，实现完整功能，全部代码

.h文件

#import <Foundation/Foundation.h>

@interface NSString (Hash)

@property (readonly) NSString *md5String;
@property (readonly) NSString *sha1String;
@property (readonly) NSString *sha256String;
@property (readonly) NSString *sha512String;

- (NSString *)hmacSHA1StringWithKey:(NSString *)key;
- (NSString *)hmacSHA256StringWithKey:(NSString *)key;
- (NSString *)hmacSHA512StringWithKey:(NSString *)key;

@end

.m文件

//
//  NSString+Hash.m
//
//  Created by Tom Corwine on 5/30/12.
//

#import "NSString+hash.h"

#import <CommonCrypto/CommonDigest.h>
#import <CommonCrypto/CommonHMAC.h>

@implementation NSString (Hash)

- (NSString *)md5String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_MD5_DIGEST_LENGTH];
    CC_MD5(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_MD5_DIGEST_LENGTH];
}

- (NSString *)sha1String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_SHA1_DIGEST_LENGTH];
    CC_SHA1(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_SHA1_DIGEST_LENGTH];
}

- (NSString *)sha256String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_SHA256_DIGEST_LENGTH];
    CC_SHA256(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_SHA256_DIGEST_LENGTH];
}

- (NSString *)sha512String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_SHA512_DIGEST_LENGTH];
    CC_SHA512(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_SHA512_DIGEST_LENGTH];
}

- (NSString *)hmacSHA1StringWithKey:(NSString *)key
{
    NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
    NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA1_DIGEST_LENGTH];
    CCHmac(kCCHmacAlgSHA1, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
    return [self stringFromBytes:(unsigned char *)mutableData.bytes length:mutableData.length];
}

- (NSString *)hmacSHA256StringWithKey:(NSString *)key
{
    NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
    NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA256_DIGEST_LENGTH];
    CCHmac(kCCHmacAlgSHA256, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
    return [self stringFromBytes:(unsigned char *)mutableData.bytes length:mutableData.length];
}

- (NSString *)hmacSHA512StringWithKey:(NSString *)key
{
    NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
    NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA512_DIGEST_LENGTH];
    CCHmac(kCCHmacAlgSHA512, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
    return [self stringFromBytes:(unsigned char *)mutableData.bytes length:mutableData.length];
}

#pragma mark - Helpers

- (NSString *)stringFromBytes:(unsigned char *)bytes length:(int)length
{
    NSMutableString *mutableString = @"".mutableCopy;
    for (int i = ; i < length; i++)
        [mutableString appendFormat:@"%02x", bytes[i]];
    return [NSString stringWithString:mutableString];
}

@end