diff --git a/bundleplugin/src/main/java/aQute/libg/cryptography/Digest.java b/bundleplugin/src/main/java/aQute/libg/cryptography/Digest.java
new file mode 100644
index 0000000..f70caa0
--- /dev/null
+++ b/bundleplugin/src/main/java/aQute/libg/cryptography/Digest.java
@@ -0,0 +1,25 @@
+package aQute.libg.cryptography;
+
+import aQute.lib.hex.*;
+
+public abstract class Digest {
+	final byte[]	digest;
+
+	protected Digest(byte[] checksum, int width) {
+		this.digest = checksum;
+		if (digest.length != width)
+			throw new IllegalArgumentException("Invalid width for digest: " + digest.length
+					+ " expected " + width);
+	}
+
+
+	public byte[] digest() {
+		return digest;
+	}
+
+	@Override public String toString() {
+		return String.format("%s(d=%s)", getAlgorithm(), Hex.toHexString(digest));
+	}
+
+	public abstract String getAlgorithm();
+}