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Objective-C SHA1 Function for the iPhone

Here’s a nice little function that will generate an SHA-1 hash digest that will match what the php sha1() function will generate if you give it the same input:

#import

@implementation SHA1

+(NSString*) digest:(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;

}


@end

This entry was posted on Friday, September 25th, 2009 at 5:30 pm and is filed under Mobile Development, Software Development. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

One Response to “Objective-C SHA1 Function for the iPhone”

  1. Mark Lorenz Says:
    April 24th, 2010 at 2:13 pm

    The PHP SHA1() function uses ASCII encoding. You can verify this by digesting a string containing something like “Ň” with your code, and with PHPs SHA1(). As long as your input string is guaranteed to contain only ASCII characters it will work fine.

    I suggest updating the code to:
    -(NSString*) digest:(NSString*)input{
    NSData *data = [input dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
    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;
    }

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