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Add support for DER-to-ECDSA signature formatting in AwsKmsSign #28

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Merged
ievgeniiskliarenko merged 2 commits into from
Jan 30, 2026
Merged

Add support for DER-to-ECDSA signature formatting in AwsKmsSign #28

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af57ca4
Add support for DER-to-ECDSA signature formatting in `AwsKmsSign`
ievgeniiskliarenko Jan 30, 2026
dbdc49a
Update vicephp/Virtue-JWT/src/JWT/Algorithms/AwsKmsSign.php
ievgeniiskliarenko Jan 30, 2026
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28 changes: 25 additions & 3 deletions vicephp/Virtue-JWT/src/JWT/Algorithms/AwsKmsSign.php
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
namespace Virtue\JWT\Algorithms;

use Virtue\Aws\KmsClient;
use Virtue\Encoding\ASN1;
use Virtue\JWT\Algorithm;
use Virtue\JWT\SignFailed;
use Virtue\JWT\SignsToken;
Expand Down Expand Up @@ -45,12 +46,33 @@ public function sign(string $msg): string
}

$result = $this->client->sign([
'Message' => $msg,
'MessageType' => 'RAW',
'Message' => $msg,
'MessageType' => 'RAW',
'SigningAlgorithm' => $this->signingAlgorithms[$this->name]
]);

Assert::string($result['Signature'], 'Issue when signing the message');
return $result['Signature'];
$signature = $result['Signature'];

$ecPadding = [
'ES256' => 32,
'ES384' => 48,
'ES512' => 66,
];
if (array_key_exists($this->name, $ecPadding)) {
$block = ASN1::decode($signature);
assert($block->type() == ASN1::SEQUENCE);

$block = ASN1::decode($block->bytes());
assert($block->type() == ASN1::INTEGER);
$r = str_pad(ltrim($block->bytes(), "\00"), $ecPadding[$this->name], "\00", STR_PAD_LEFT);

$block = ASN1::decode($block->rest());
assert($block->type() == ASN1::INTEGER);
$s = str_pad(ltrim($block->bytes(), "\00"), $ecPadding[$this->name], "\00", STR_PAD_LEFT);
$signature = $r . $s;
}

return $signature;
}
}
113 changes: 113 additions & 0 deletions vicephp/Virtue-JWT/tests/JWT/Algorithms/AwsKmsSignTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
use Mockery as M;
use PHPUnit\Framework\TestCase;
use Virtue\Aws\KmsClient;
use Virtue\Encoding\ASN1;
use Virtue\JWT\SignFailed;

class AwsKmsSignTest extends TestCase
Expand Down Expand Up @@ -57,4 +58,116 @@ public function testSingMessage(): void

$this->assertEquals('<signature>', $signature);
}

public function testSignMessageES256(): void
{
$message = 'message';
$r = str_repeat("\x01", 32);
$s = str_repeat("\x02", 32);
$derSignature = ASN1::seq(ASN1::uint($r), ASN1::uint($s))->encode();

$handler = new MockHandler();
$handler->append(function (CommandInterface $cmd) use ($derSignature) {
$this->assertEquals('ECDSA_SHA_256', $cmd->offsetGet('SigningAlgorithm'));
return new Result(['Signature' => $derSignature]);
});

$client = new KmsClient('key/alias', [
'version' => 'latest',
'region' => 'eu-west-1',
'handler' => $handler,
'credentials' => ['key' => '', 'secret' => '']
]);

$signer = new AwsKmsSign('ES256', $client);
$signature = $signer->sign($message);

$this->assertEquals($r . $s, $signature);
$this->assertEquals(64, strlen($signature));
}

public function testSignMessageES384WithPadding(): void
{
$message = 'message';
// ES384 expects 48 bytes for each component
$r = str_repeat("\x01", 30); // Needs padding
$s = str_repeat("\x02", 48);
$derSignature = ASN1::seq(ASN1::uint($r), ASN1::uint($s))->encode();

$handler = new MockHandler();
$handler->append(function (CommandInterface $cmd) use ($derSignature) {
$this->assertEquals('ECDSA_SHA_384', $cmd->offsetGet('SigningAlgorithm'));
return new Result(['Signature' => $derSignature]);
});

$client = new KmsClient('key/alias', [
'version' => 'latest',
'region' => 'eu-west-1',
'handler' => $handler,
'credentials' => ['key' => '', 'secret' => '']
]);

$signer = new AwsKmsSign('ES384', $client);
$signature = $signer->sign($message);

$expectedR = str_pad($r, 48, "\x00", STR_PAD_LEFT);
$this->assertEquals($expectedR . $s, $signature);
$this->assertEquals(96, strlen($signature));
}

public function testSignMessageES512(): void
{
$message = 'message';
// ES512 expects 66 bytes for each component
$r = str_repeat("\x01", 66);
$s = str_repeat("\x02", 66);
$derSignature = ASN1::seq(ASN1::uint($r), ASN1::uint($s))->encode();

$handler = new MockHandler();
$handler->append(function (CommandInterface $cmd) use ($derSignature) {
$this->assertEquals('ECDSA_SHA_512', $cmd->offsetGet('SigningAlgorithm'));
return new Result(['Signature' => $derSignature]);
});

$client = new KmsClient('key/alias', [
'version' => 'latest',
'region' => 'eu-west-1',
'handler' => $handler,
'credentials' => ['key' => '', 'secret' => '']
]);

$signer = new AwsKmsSign('ES512', $client);
$signature = $signer->sign($message);

$this->assertEquals($r . $s, $signature);
$this->assertEquals(132, strlen($signature));
}

public function testSignMessageES256WithNegativeIntegers(): void
{
$message = 'message';
// 0x80 is 128, which is negative in 8-bit signed integer
$r = "\x80" . str_repeat("\x01", 31);
$s = "\x80" . str_repeat("\x02", 31);
// ASN1::uint should add a leading \00 if the high bit is set
$derSignature = ASN1::seq(ASN1::uint($r), ASN1::uint($s))->encode();

$handler = new MockHandler();
$handler->append(function (CommandInterface $cmd) use ($derSignature) {
return new Result(['Signature' => $derSignature]);
});

$client = new KmsClient('key/alias', [
'version' => 'latest',
'region' => 'eu-west-1',
'handler' => $handler,
'credentials' => ['key' => '', 'secret' => '']
]);

$signer = new AwsKmsSign('ES256', $client);
$signature = $signer->sign($message);

$this->assertEquals($r . $s, $signature);
$this->assertEquals(64, strlen($signature));
}
}