+ (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;  

}  

+ (NSString *) md5:(NSString *) input  
{  
    const char *cStr = [input UTF8String];  
    unsigned char digest[16];  
    CC_MD5( cStr, strlen(cStr), digest ); // This is the md5 call  

    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;  

}  

需要导入头文件

#import <CommonCrypto/CommonDigest.h>

Resource Reference

• http://blog.csdn.net/matrixhero/article/details/8725460