base64 and sha1 on iPhone

Lets be straight: here are two functions to add to your code to have base64 and hexadecimal version of the sha1 hash of an NSString.

To use it, simply copy the code in your class and use as this:

#import <CommonCrypto/CommonDigest.h>
...
NSString *b64_hash = [self b64_sha1:@"some NSString to be sha1'ed"];
...
NSString *hex_hash = [self hex_sha1:@"some NSString to be sha1'ed"];

The base64 algorithm must be programmed by hand on iPhone!


- (unsigned char *)sha1:(NSString *)baseString result:(unsigned char *)result {
    char *c_baseString=(char *)[baseString UTF8String];
    CC_SHA1(c_baseString, strlen(c_baseString), result);
    return result;
}

- (NSString *)base64:(unsigned char *)result {
    NSString *password=[[NSString alloc] init];
    static const unsigned char cb64[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    for (int i=0; i<CC_SHA1_DIGEST_LENGTH; i+=3) {
        password=[password stringByAppendingFormat:@"%c%c%c%c",
            cb64[(result[i] &0xFC)>>2],
            cb64[((result[i] & 0x03) << 4)
                | ((result[i + 1] & 0xF0) >> 4)],
            cb64[((result[i + 1] & 0x0F) << 2)
                | ((result[i + 2] & 0xC0) >> 6)],
            cb64[result[i+2]&0x3F]
                ];            
    }
    return password;
}

- (NSString *)hexadecimalRepresentation:(unsigned char *)result {
    NSString *password=[[NSString alloc] init];
    for (int i=0; i<CC_SHA1_DIGEST_LENGTH; i++) {
        password=[password stringByAppendingFormat:@"%02x", result[i]];
    }
    return password;
}

- (NSString *)b64_sha1:(NSString *)inputString {
    unsigned char result[CC_SHA1_DIGEST_LENGTH+1];
    [self sha1:inputString result:result];
    return [self base64:result];
}

- (NSString *)hex_sha1:(NSString *)inputString {
    unsigned char result[CC_SHA1_DIGEST_LENGTH+1];
    [self sha1:inputString result:result];
    return [self hexadecimalRepresentation:result];
}

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Published on 2010-09-02
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Yann Esposito©
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