iOS開發之Objective-c的MD5/SHA1加密算法的實現

Objective-c 實現 MD5 和 SHA1 算法相對還是比較簡單的，可以直接調用系統的 C/C++ 共享庫來實現調用
MD5 即 Message Digest Algorithm 5（信息 - 摘要算法 5），用於確保信息傳輸完整一致。是計算機廣泛使用的雜湊算法之一
SHA 即 Secure Hash Algorithm（安全散列算法) 是美國國家安全局 (NSA) 設計，美國國家標準與技術研究院 (NIST) 發布的一系列密碼散列函數。

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 = \[NSMutableString stringWithCapacity:CC\_MD5\_DIGEST\_LENGTH \* 2\];

for(int i = 0; i < CC\_MD5\_DIGEST\_LENGTH; i++)
    \[output appendFormat:@"%02x", digest\[i\]\];

return output;

}

SHA1 加密方式

- (NSString*) sha1
{
const char *cstr = [self cStringUsingEncoding];
NSData *data = [NSData dataWithBytes length.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;

}

當然也可以結合 BASE64 來使用，這裡的 BASE64 編碼使用 GTMBase64 實現，需要導入

- (NSString *) sha1_base64
{
const char *cstr = [self cStringUsingEncoding];
NSData *data = [NSData dataWithBytes length.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 length_MD5_DIGEST_LENGTH];
base64 = [GTMBase64 encodeData];

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

通過拓展 NSString，實現完整功能，全部代碼

@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];
NSData *data = [NSData dataWithBytes length.length];

uint8_t digest[CC_SHA1_DIGEST_LENGTH];

CC_SHA1(data.bytes, data.length, digest);

NSMutableString* output = [NSMutableString stringWithCapacity_SHA1_DIGEST_LENGTH * 2];

for(int i = 0; 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 = \[NSMutableString stringWithCapacity:CC\_MD5\_DIGEST\_LENGTH \* 2\];

for(int i = 0; i < CC\_MD5\_DIGEST\_LENGTH; i++)
    \[output appendFormat:@"%02x", digest\[i\]\];

return output;

}

(NSString *) sha1_base64
{
const char *cstr = [self cStringUsingEncoding];
NSData *data = [NSData dataWithBytes length.length];

uint8_t digest[CC_SHA1_DIGEST_LENGTH];

CC_SHA1(data.bytes, data.length, digest);

NSData * base64 = [[NSData alloc]initWithBytes length_SHA1_DIGEST_LENGTH];
base64 = [GTMBase64 encodeData];

NSString * output = [[NSString alloc] initWithData encoding];
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 length_MD5_DIGEST_LENGTH];
base64 = [GTMBase64 encodeData];

NSString * output = [[NSString alloc] initWithData encoding];
return output;
}
(NSString *) base64
{
NSData * data = [self dataUsingEncoding allowLossyConversion];
data = [GTMBase64 encodeData];
NSString * output = [[NSString alloc] initWithData encoding];
return output;
}
@end

實現時不要忘記導入 CC 相關的庫的頭文件
CommonCrypto/CommonDigest.h