1 files changed, 41 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/signers/DSAKCalculator.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/signers/DSAKCalculator.java
new file mode 100644
index 000000000..6c8e1dc8a
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/signers/DSAKCalculator.java
@@ -0,0 +1,41 @@
+package org.spongycastle.crypto.signers;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+/**
+ * Interface define calculators of K values for DSA/ECDSA.
+ */
+public interface DSAKCalculator
+{
+    /**
+     * Return true if this calculator is deterministic, false otherwise.
+     *
+     * @return true if deterministic, otherwise false.
+     */
+    boolean isDeterministic();
+
+    /**
+     * Non-deterministic initialiser.
+     *
+     * @param n the order of the DSA group.
+     * @param random a source of randomness.
+     */
+    void init(BigInteger n, SecureRandom random);
+
+    /**
+     * Deterministic initialiser.
+     *
+     * @param n the order of the DSA group.
+     * @param d the DSA private value.
+     * @param message the message being signed.
+     */
+    void init(BigInteger n, BigInteger d, byte[] message);
+
+    /**
+     * Return the next valid value of K.
+     *
+     * @return a K value.
+     */
+    BigInteger nextK();
+}