1 files changed, 13 insertions, 5 deletions
diff --git a/src/crypto/chacha20.h b/src/crypto/chacha20.h
index a305977bcd..5a4674f4a8 100644
--- a/src/crypto/chacha20.h
+++ b/src/crypto/chacha20.h
@@ -8,7 +8,8 @@
 #include <stdint.h>
 #include <stdlib.h>
 
-/** A PRNG class for ChaCha20. */
+/** A class for ChaCha20 256-bit stream cipher developed by Daniel J. Bernstein
+    https://cr.yp.to/chacha/chacha-20080128.pdf */
 class ChaCha20
 {
 private:
@@ -17,10 +18,17 @@ private:
 public:
     ChaCha20();
     ChaCha20(const unsigned char* key, size_t keylen);
-    void SetKey(const unsigned char* key, size_t keylen);
-    void SetIV(uint64_t iv);
-    void Seek(uint64_t pos);
-    void Output(unsigned char* output, size_t bytes);
+    void SetKey(const unsigned char* key, size_t keylen); //!< set key with flexible keylength; 256bit recommended */
+    void SetIV(uint64_t iv); // set the 64bit nonce
+    void Seek(uint64_t pos); // set the 64bit block counter
+
+    /** outputs the keystream of size <bytes> into <c> */
+    void Keystream(unsigned char* c, size_t bytes);
+
+    /** enciphers the message <input> of length <bytes> and write the enciphered representation into <output>
+     *  Used for encryption and decryption (XOR)
+     */
+    void Crypt(const unsigned char* input, unsigned char* output, size_t bytes);
 };
 
 #endif // BITCOIN_CRYPTO_CHACHA20_H