chore: split sha256 in base sha class

1 files changed, 57 insertions, 0 deletions

diff --git a/include/sha.h b/include/sha.h
new file mode 100644
index 0000000..255c769
--- /dev/null
+++ b/include/sha.h
@@ -0,0 +1,57 @@
+// This file is part of a crypto library, exam for the Algorithms class.
+// All of these files are under MIT license.
+//
+// SHA declaration document:
+// https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf
+
+#ifndef HMACSHA256_SHA_H_
+#define HMACSHA256_SHA_H_
+
+#include<cstdint>
+#include<array>
+
+namespace hmacsha256 {
+class SHA {
+public:
+    SHA() {
+        digest_ = new uint8_t[32];
+    }
+
+    ~SHA() {
+        delete digest_;
+    }
+
+    // get digest as array of bytes
+    virtual uint8_t* digest() = 0;
+
+    virtual std::string hexdigest() = 0;
+protected:
+    uint8_t* digest_;
+
+    // work variables: a, b, c, d, e, f, g, h
+    uint32_t vars_[8];
+
+    // data message, in bytes
+    // M,  "message to be hashed"
+    uint8_t message_[64];
+
+    // length L of the original message
+    uint32_t message_l_;
+
+    // lenght of bits
+    uint64_t bit_len_;
+
+    // the constructor
+    virtual void init(const uint8_t* data, uint32_t length) = 0;
+
+    // padding
+    virtual void pad() = 0;
+
+    // main function
+    virtual void transform() = 0;
+};
+
+
+} // namespace hmacsha256
+
+#endif // HMACSHA256_SHA_H_