Add AuthzClientCryptoProvider for authorization client cryptographic operations

[ShashankFC]

Test 3

Summary by CodeRabbit

Release Notes

• New Features

  • Enhanced cryptographic support with ECDSA algorithm implementation for authorization client operations.
  • Improved crypto provider selection with priority ordering mechanism.

• Tests

  • Added test coverage for ECDSA algorithm variants (ES256, ES384, ES512).

• Chores

  • Added testing framework dependencies.

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Replicated from ai-code-review-evaluation/keycloak-coderabbit#3

[Copilot]

Pull request overview

This PR introduces cryptographic provider functionality for the authorization client, enabling it to handle ECDSA signature operations independently. The implementation adds a priority ordering mechanism to allow multiple crypto providers to coexist on the classpath.

Changes:

• Added AuthzClientCryptoProvider with ECDSA algorithm support and ASN.1 encoding/decoding utilities
• Implemented priority ordering for crypto provider selection based on the order() method
• Added comprehensive test coverage for ECDSA algorithms (ES256, ES384, ES512)

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
authz/client/src/main/java/org/keycloak/authorization/client/util/crypto/AuthzClientCryptoProvider.java	Implements new crypto provider with ECDSA operations for authorization client
authz/client/src/main/java/org/keycloak/authorization/client/util/crypto/ASN1Encoder.java	Provides ASN.1 DER encoding utilities for ECDSA signatures
authz/client/src/main/java/org/keycloak/authorization/client/util/crypto/ASN1Decoder.java	Provides ASN.1 DER decoding utilities for ECDSA signatures
authz/client/src/test/java/org/keycloak/authorization/client/test/ECDSAAlgorithmTest.java	Tests ECDSA algorithm variants with signature conversion operations
common/src/main/java/org/keycloak/common/crypto/CryptoProvider.java	Adds order() method to enable provider priority ordering
common/src/main/java/org/keycloak/common/crypto/CryptoIntegration.java	Updates provider detection to sort by order and handle multiple providers
crypto/default/src/main/java/org/keycloak/crypto/def/DefaultCryptoProvider.java	Implements order() returning 200
crypto/fips1402/src/main/java/org/keycloak/crypto/fips/FIPS1402Provider.java	Implements order() returning 200
crypto/elytron/src/main/java/org/keycloak/crypto/elytron/WildFlyElytronProvider.java	Implements order() returning 200
authz/client/src/main/resources/META-INF/services/org.keycloak.common.crypto.CryptoProvider	Registers AuthzClientCryptoProvider as a service provider
authz/client/src/main/java/org/keycloak/authorization/client/AuthzClient.java	Initializes crypto integration on client creation
authz/client/pom.xml	Adds JUnit and Hamcrest test dependencies

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[Copilot]

String concatenation inside a loop should use StringBuilder.append() without the + operator. Replace with builder.append(foundProviders.get(i).getClass().getName()).append(\", \").

[Copilot]

Lines 114-115 create encoder instances that are never used, resulting in dead code. These lines should be removed as the actual encoding is performed in lines 117-121.

Suggested change

	ASN1Encoder.create().write(rBigInteger);
	ASN1Encoder.create().write(sBigInteger);