I'm trying to calculate the hash over a public key on both iOS (Swift) and macOS (terminal & OpenSSL), but both platforms export the key in a slightly different format.
My Swift code extracts the sequence containing both the modulus and exponent (according to Apple this is the PKCS#1 container).
let export = SecKeyCopyExternalRepresentation(publicKey, nil)! as Data
let hash = SHA256.hash(data: export)
// SHA256 digest: 57fc8238c609045b7c0b546f58d5f797ebec4e39eff481459edfb67bd850834d
print(hash)
Now when I do similar things with the terminal I get a different output.
openssl rsa -pubin -outform DER | openssl dgst -sha256
# writing RSA key
# 0ee9c99ef4ca3316e90dde23925bc9a670fa309d6f4663bb5d42050b5089b086
The latter one is cause by OpenSSL wrapping the output in a fuller structured ASN.1 container.
SEQUENCE (ASN.1 container)
SEQUENCE
OID (RSA algorithm)
NULL
BITSTRING
SEQUENCE (iOS container)
INTEGER (Modulus)
INTEGER (Exponent)
How can I use OpenSSL to export the key into only the sequence iOS expects, so the has will be the same for both commands?
It turns out OpenSSL has an undocumented parameter -RSAPublicKey_out that outputs the same data that SecKeyCopyExternalRepresentation does.
openssl rsa -pubin -RSAPublicKey_out -outform DER | openssl dgst -sha256
This provides the same digest for both iOS and macOS
Related
I use the following command in Powershell to sign a base64 encoded string. It is reading currently from a file. Can I also let it directly take it from a variable?
openssl dgst -sha256 -sign jwtRS256.key -binary $payload | openssl enc -base64 -
It works if I use the following:
openssl dgst -sha256 -sign jwtRS256.key -binary payload.b64 | openssl enc -base64 -A
Maybe it is very simple or it is not possible what I try to achieve.
This line is part of some steps that I try to follow to sign a concatenate of header.payload for JWT geneartion by using openssl.
I have the command openssl dgst -sha256 -binary _your_file_path_ | openssl enc -base64 I use in terminal to get an output for a jar file that matches what AWS Lambda uses to hash.
I want to program that in Java, but I am having trouble understanding exactly what is going on in that line, so that I can go through each step in my code. Obviously, there is mode than just hashing in SHA256, because when I do that the output does not match.
Could someone help explain the steps that line is completing in a simple way for me?
You need to break the command down to understand what is going on.
The first part of the command:
openssl dgst -sha256 -binary <file> gives you a SHA256 binary checksum for the file.
The second part of the command:
openssl enc -base64 encodes the SHA256 binary checksum to Base64.
So to replicate in Java, you just need to carry out those same steps:
Calculate a SHA256 binary checksum.
Base64 encode the SHA256 binary checksum.
Without you posting the command you used to try and get a SHA256 checksum separately to the command you did post, I'm guessing the reason you were probably getting a different hash is because by default a checksum seems to output in hexadecimal.
See my example below and how the results are completely different.
# Hexadecimal
$ openssl dgst -sha256 data.csv
SHA256(data.csv)= 114811b0b8998cb9853a5379598021410feddf69bb2ee7b7145d052a7e9b5d45
# Binary (note the usage of the -binary flag)
$ openssl dgst -sha256 -binary data.csv
H:SyY!Ai.]*~]E
If you then Base64 encode the hexadecimal checksum above, and the binary one, you'll also get two completely different results, as you can see below.
# Hexadecimal
$ printf 114811b0b8998cb9853a5379598021410feddf69bb2ee7b7145d052a7e9b5d45 | openssl enc -base64
MTE0ODExYjBiODk5OGNiOTg1M2E1Mzc5NTk4MDIxNDEwZmVkZGY2OWJiMmVlN2I3
MTQ1ZDA1MmE3ZTliNWQ0NQ==
# Binary
$ printf 'H:SyY!Ai.]*~]E' | openssl enc -base64
SDpTeVkhQWkuXSp+XUU=
For those, who TLDR. To get the same result as in this cat FILENAME.js | openssl dgst -sha256 -binary | openssl base64 -A command you should do the following conversions:
1) your content -> sha256 (you'll get the hexadecimal number, not a text)
2) hexadecimal -> binary
3) binary -> base64
I need to generate a development key hash for my facebook app, so I downloaded openssl x64 for windows from (https://code.google.com/archive/p/openssl-for-windows/downloads) and used
keytool -exportcert -alias androiddebugkey -keystore %HOMEPATH%\.android\debug.keystore | openssl sha1 -binary | openssl base64
But this generates a 27 character encoding; I need a 28 character one. The paths for my openssl and debug.keystore are correct, but it still does not generate a correct length hash.
My hash ended with a '=', which I misconstrued as part of the code. With the other 27 characters, that resulted in 28 characters.
Does anyone knows how the dgst function of the Openssl library manage the input value? I mean, it considers the input value as ASCII characters or in any other charset encoding?
I'm trying to input hexadecimal values but can't find how to do this:
$echo -n "FFFF" | openssl dgst -sha256
The result is different from the obtained by other ways (e.g. Java's MessageDigest) with the hexadecimal number '0xFFFF' as input.
Normally dgst takes ASCII input, to get hash of 0xFFFF try:
printf "\xFF\xFF" | openssl dgst -sha256
The result should be: ca2fd00fa001190744c15c317643ab092e7048ce086a243e2be9437c898de1bb
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I am new to perl so this might be very basic, but i am finding no way around this problem. I am trying to sign my data which has to be send over https connection using my ssh private key(id_rsa). I am not able to do so using perl and i am at it for days. Please someone show me a possible way to do so. If any more info is needed please ask me. Thanks in advance
My code as asked is
#!/usr/bin/perl
use File::Slurp qw(read_file);
use Crypt::OpenSSL::RSA;
use MIME::Base64 qw( decode_base64 encode_base64 );
my $keystring = read_file( 'id_rsa' );
my $privatekey = Crypt::OpenSSL::RSA->new_private_key($keystring);
$privatekey->use_pkcs1_padding();
my $datatosign = "hello";
my $signature = $privatekey->sign($datatosign);
my $base64 = encode_base64($signature);
print "$base64";
The error coming on running it is RSA.xs:178: OpenSSL error: unsupported encryption at test.pl line 7.
NOTE: As discussed in the comments, I am using a passphrase protected id_rsa.
So, leaving out the perl, and just doing this by hand with openssl
Checking the key:
ssh-keygen -t rsa -f test_id
openssl rsa -in test_id -check
RSA key ok
So we do have a 'valid' RSA private key there, which we should be able to use for encrpyting.
Generating a comparison key
However if you use openssl to generate a key pair
openssl genrsa -out openssl_gen_rsa
openssl rsa -in openssl_gen_rsa -pubout -out openssl_gen_rsa.out
Looks like the command you need is:
openssl rsautl -inkey test_id -in test_file.txt -encrypt -out test_file.enc
(That encrypts with the private key, so you'd decrypt with the public key - that's actually pretty similar to signing - normally you wouldn't do this).
The problem is - if you compare your generated -public- keys they don't match. test_id.pub looks like (Yes, this is the real one, and no, I did only use it for testing!)
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDKfjRD+Gb5EE+SgOy7eoT0siQaAqfSY7KI2wkdrdygnJ+ccW/uMCtCVPhpz00u3EW2Gz1WI DteLKppjvUem1lKb8Tt2EWBQGyFOYKp44r3AJZgTcxLeDdqSUoiPsjWf1aUqy2Z1fBgtG+QOa7bpA8km6CbsORYX/TVg4B6vvdkkH K8WcmzBBF3rGsTCM3VXPp56bPoMCbwCsXvIjejmq+JdGHyxUmCxe1PrPyvmoYX3OUqpFBYIjeLWGDI9EXS6jA/r7viIAxdllvulPg IJ+4mdYzKN+T1ME0X0c+ZdFTMdeUnB9/TZmJr1j8Q/4SQm+3J9CiwtVXKxdkDsDObkcDp root#raspberrypi
Where my generated key file looks like:
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDG8i33AuEp1wqbJgkEsnOmQim3
QT76B/oxsVGfJEDX3h4A6CD+ypBbfhhIn0GlfHanYvcGlpOJIlk3fzspbZNeoPJS
T4a0zQ0z8uJkugl8utyl9WR4tpgBRmzXZ42T/f4QSNqjDxUidRp5zPnXs9aRDtWb
XptswiGL3eVHMpbSnwIDAQAB
-----END PUBLIC KEY-----
I can use my generated pair (encrypting using public key, decrypting using private):
openssl rsautl -inkey openssl_gen_rsa.out -pubin -in test_file.txt -encrypt -out test_file.enc2
openssl rsautl -inkey openssl_gen_rsa -in test_file.enc2 -decrypt
This works.
Turning your OpenSSH private key into an RSA public key
So if we run your ssh private key through openssl:
openssl rsa -in test_id -pubout -out test_id.openssl.pub
We get:
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAyn40Q/hm+RBPkoDsu3qE
9LIkGgKn0mOyiNsJHa3coJyfnHFv7jArQlT4ac9NLtxFths9ViA7XiyqaY71HptZ
Sm/E7dhFgUBshTmCqeOK9wCWYE3MS3g3aklKIj7I1n9WlKstmdXwYLRvkDmu26QP
JJugm7DkWF/01YOAer73ZJByvFnJswQRd6xrEwjN1Vz6eemz6DAm8ArF7yI3o5qv
iXRh8sVJgsXtT6z8r5qGF9zlKqRQWCI3i1hgyPRF0uowP6+74iAMXZZb7pT4CCfu
JnWMyjfk9TBNF9HPmXRUzHXlJwff02Zia9Y/EP+EkJvtyfQosLVVysXZA7Azm5HA
6QIDAQAB
-----END PUBLIC KEY-----
Which isn't even a remotely similar encoding to the id_rsa.pub file - and I think therefore why you have this problem.
openssl rsautl -inkey test_id.openssl.pub -pubin -in test_file.txt -encrypt -out test_file.openssl.pub.enc
Now works, and you can decrypt it using your test_id private key:
openssl rsautl -inkey test_id -in test_file.openssl.pub.enc -decrypt
So yes - for some reason the public key generated by ssh-keygen isn't the same format as openssl is expecting, so it's not going to work.
using an openssh key to verify
Anyway, back to your original example - using the private key to generate a signature:
openssl rsautl -sign -inkey test_id -in test_file.txt -out test_file.sig
openssl rsautl -verify -in test_file.sig -inkey test_id.openssl.pub -pubin
But the verify step won't work using the generated ssh key.
So does this answer your question as to whether it's possible? I'm afraid I don't know how the ssh public key differs from a 'normal' rsa public key.
I suspect your code therefore doesn't even need to be as complicated as it - I don't think you need to pkcs pad your key file.
E.g.
#!/usr/bin/perl
use strict;
use warnings;
use File::Slurp qw(read_file);
use Crypt::OpenSSL::RSA;
use MIME::Base64 qw( decode_base64 encode_base64 );
my $keystring = read_file ('test_id');
my $privatekey = Crypt::OpenSSL::RSA->new_private_key($keystring);
my $datatosign = "hello";
my $signature = $privatekey->sign($datatosign);
my $base64 = encode_base64($signature);
print "Signature:\n";
print "$base64";
my $public_key_text = $privatekey-> get_public_key_string();
print "Public Key:\n";
print $public_key_text;
my $rsa_pub = Crypt::OpenSSL::RSA->new_public_key ( $public_key_text );
print "Signed correctly\n" if ($rsa_pub->verify($datatosign, decode_base64($base64)));
This seems to work. (note lack of pkcs padding line).
Encrypted private key (passphrase)
Following from comments:
If your id_rsa has a passphrase set you'll have something like this:
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-128-CBC,B44716076DD8B7D2B5E909BB8F70B48B
You can decrypt this by hand using openssl again:
openssl rsa -in test_id.enc
Enter pass phrase for test_id.enc:
Or:
openssl rsa -in test_id.enc -passin pass:testpass
I'm less sure how you do this using Crypt::OpenSSL::RSA - there doesn't seem to be any option to specify a passphrase to a private key.
I think you therefore need to use Crypt::CBC to decrypt the private key first. I can't test this, because I've got a load of dependencies to install.
A bit of googling suggests that you might be able to use Crypt::PK::RSA instead.
And as an alernative - use IPC::Open2 and start an openssl process to do the things without using libraries at all.
e.g.
my $keystring = `openssl rsa -passin pass:testpass -in test_id.enc`;
Not very nice, but it'll work. (and test it does actually work)