Digest sha256 returns gibberish

invalid_logic has asked for the wisdom of the Perl Monks concerning the following question:

I was able to get Digest::SHA working but it's returning gibberish. I'm not sure why. $data1 and $data2 are byte strings in hex. There is no '0x' preceeding the byte strings.

    $digest = sha256_hex($data1 . $data2);
        $digest2 = sha256($data1 . $data2);
[download]

With '$digest' I get a valid result, but with 'digest2' I get gibberish.

print "This is a hexdigest->" . $digest, "\n";
print "This is a digest->" . $digest2, "\n";
This is a digest->&#65533;&#65533;j6&#65533;&#65533;U&#981;&#65533;&#
+65533;Y&#65533;b&#65533;S&#65533;A&#65533;&#65533;i&#65533;6&#65533;&
+#1142;&#65533;,
[download]

What did I do wrong?

Comment on Digest sha256 returns gibberish Select or Download Code

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Re: Digest sha256 returns gibberish by Athanasius (Archbishop) on Aug 08, 2012 at 03:16 UTC
From Digest¹: binary This is the most compact form, but it is not well suited for printing or embedding in places that can't handle arbitrary data. Consider using `sha256_base64`, or stick with `sha256_hex`: `#! perl use strict; use warnings; use Digest::SHA qw(sha256_hex sha256_base64); my $data1 = '0123456789ABCDEF'; my $data2 = 'FEDCBA9876543210'; my $digest1 = sha256_hex ($data1 . $data2); my $digest3 = sha256_base64($data1 . $data2); print "This is a hexdigest->" . $digest1, "\n"; print "This is a base64digest->" . $digest3, "\n";` [download] Output: `This is a hexdigest->b4a5e0ad9fce13bf90bcb09147ba9200431389e28fa40eaa2 +a0dcd41d6544470 This is a base64digest->tKXgrZ/OE7+QvLCRR7qSAEMTieKPpA6qKg3NQdZURHA` [download] What output format do you need? ¹ Referencing Digest, because SHA says: “The programming interface is easy to use: it’s the same one found in CPAN’s Digest module.” Athanasius <°(((>< contra mundum	[reply] [d/l] [select]
Re^2: Digest sha256 returns gibberish by invalid_logic (Initiate) on Aug 08, 2012 at 03:50 UTC
I'm hashing in order to verify pre-existing hash values that were generated with C++. The process and each steps results are documented but I'm following along in perl. So whatever the result I get, should match the authors examples. The following is the concatenated result: `800C28FCA386C7A227600B2FE50B7CAE11EC86D3BF1FBE471BE89827E19D72AA1D` Which needs to match the following string after hashing with sha256*: `8147786C4D15106333BF278D71DADAF1079EF2D2440A4DDE37D747DED5403592` I've tried with sha256_base64 and it doesn't match.	[reply] [d/l] [select]
Re^3: Digest sha256 returns gibberish by Athanasius (Archbishop) on Aug 08, 2012 at 04:51 UTC
Using the online SHA-256 hash calculator at http://www.xorbin.com/tools/sha256-hash-calculator, the hash of: `800C28FCA386C7A227600B2FE50B7CAE11EC86D3BF1FBE471BE89827E19D72AA1D` [download] is given as: `e2e4146a36e9c455cf95a4f259f162c353cd419cc3fd0e69ae36d7d1b6cd2c09` [download] which is the exact result returned by `Digest::SHA::sha256_hex`: `This is a hexdigest->e2e4146a36e9c455cf95a4f259f162c353cd419cc3fd0e69a +e36d7d1b6cd2c09` [download] Where did you get the expected result beginning `81477...`? Update 1: Same result at http://hash.online-convert.com/sha256-generator. Update 2: ++aitap for the solution below. Athanasius <°(((>< contra mundum	[reply] [d/l] [select]
Re^4: Digest sha256 returns gibberish by invalid_logic (Initiate) on Aug 08, 2012 at 05:09 UTC
Re^3: Digest sha256 returns gibberish by aitap (Curate) on Aug 08, 2012 at 07:33 UTC
You need to calculate sha256 on the binary form of this data, not on the hexademical string: `$ perl '-MDigest::SHA "sha256_hex"' -E'say sha256_hex(pack("H*","800C2 +8FCA386C7A227600B2FE50B7CAE11EC86D3BF1FBE471BE89827E19D72AA1D"))' 8147786c4d15106333bf278d71dadaf1079ef2d2440a4dde37d747ded5403592` [download] Sorry if my advice was wrong.	[reply] [d/l]

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