diff --git a/src/main/java/net/oauth/jsontoken/crypto/RsaSHA1Verifier.java b/src/main/java/net/oauth/jsontoken/crypto/RsaSHA1Verifier.java
deleted file mode 100644
index 5f9d379..0000000
--- a/src/main/java/net/oauth/jsontoken/crypto/RsaSHA1Verifier.java
+++ /dev/null
@@ -1,43 +0,0 @@
-package net.oauth.jsontoken.crypto;
-
-import java.security.InvalidKeyException;
-import java.security.NoSuchAlgorithmException;
-import java.security.PublicKey;
-import java.security.Signature;
-import java.security.SignatureException;
-
-public class RsaSHA1Verifier implements Verifier {
-
-  private final PublicKey verificationKey;
-  private final Signature signer;
-
-  /**
-   * Public Constructor.
-   *
-   * @param verificationKey the key used to verify the signature.
-   */
-  public RsaSHA1Verifier(PublicKey verificationKey) {
-    this.verificationKey = verificationKey;
-    try {
-      this.signer = Signature.getInstance("SHA1withRSA");
-      this.signer.initVerify(verificationKey);
-    } catch (NoSuchAlgorithmException e) {
-      throw new IllegalStateException("platform is missing RSAwithSHA1 signature alg", e);
-    } catch (InvalidKeyException e) {
-      throw new IllegalStateException("key is invalid", e);
-    }
-  }
-
-  @Override
-  public void verifySignature(byte[] source, byte[] signature) throws SignatureException {
-    try {
-      signer.initVerify(verificationKey);
-    } catch (InvalidKeyException e) {
-      throw new RuntimeException("key someone become invalid since calling the constructor");
-    }
-    signer.update(source);
-    if (!signer.verify(signature)) {
-      throw new SignatureException("signature did not verify");
-    }
-  }
-}
diff --git a/src/main/java/net/oauth/jsontoken/crypto/SignatureAlgorithm.java b/src/main/java/net/oauth/jsontoken/crypto/SignatureAlgorithm.java
index 4cc77be..c5bf63c 100644
--- a/src/main/java/net/oauth/jsontoken/crypto/SignatureAlgorithm.java
+++ b/src/main/java/net/oauth/jsontoken/crypto/SignatureAlgorithm.java
@@ -17,9 +17,23 @@
 
 /** Enum of the signature algorithms supported by this package. */
 public enum SignatureAlgorithm {
+  /** HMAC with SHA-256 */
   HS256("SHA256"),
+  /**
+   * HMAC with SHA-1
+   *
+   * @deprecated SHA-1 is vulnerable to collision attacks
+   */
+  @Deprecated
   HS1("SHA1"),
+  /** RSA with SHA-256 */
   RS256("SHA256"),
+  /**
+   * RSA with SHA-1
+   *
+   * @deprecated SHA-1 is vulnerable to collision attacks
+   */
+  @Deprecated
   RS1("SHA1");
 
   private final String hashAlg;