diff --git a/src/base64.cpp b/src/base64.cpp
new file mode 100644
index 0000000..2592887
--- /dev/null
+++ b/src/base64.cpp
@@ -0,0 +1,138 @@
+#include <base64.hpp>
+#include <cassert>
+
+namespace base64
+{
+bool base64_encode(const gsl::cstring_span<> &input, std::string &output)
+{
+    static const char encoding_data[] =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+    unsigned int input_length = input.size();
+
+    // allocate space for output string
+    output.clear();
+    output.reserve(((input_length + 2) / 3) * 4);
+
+    // for each 3-bytes sequence from the input, extract 4 6-bits sequences and
+    // encode using
+    // encoding_data lookup table.
+    // if input do not contains enough chars to complete 3-byte sequence,use pad
+    // char '='
+    for (unsigned int i = 0; i < input_length; i++) {
+        int base64code0 = 0;
+        int base64code1 = 0;
+        int base64code2 = 0;
+        int base64code3 = 0;
+
+        base64code0 = (input[i] >> 2) & 0x3f;  // 1-byte 6 bits
+        output += encoding_data[base64code0];
+        base64code1 = (input[i] << 4) & 0x3f;  // 1-byte 2 bits +
+
+        if (++i < input_length) {
+            base64code1 |= (input[i] >> 4) & 0x0f;  // 2-byte 4 bits
+            output += encoding_data[base64code1];
+            base64code2 = (input[i] << 2) & 0x3f;  // 2-byte 4 bits +
+
+            if (++i < input_length) {
+                base64code2 |= (input[i] >> 6) & 0x03;  // 3-byte 2 bits
+                base64code3 = input[i] & 0x3f;          // 3-byte 6 bits
+                output += encoding_data[base64code2];
+                output += encoding_data[base64code3];
+            } else {
+                output += encoding_data[base64code2];
+                output += '=';
+            }
+        } else {
+            output += encoding_data[base64code1];
+            output += '=';
+            output += '=';
+        }
+    }
+
+    return true;
+}
+
+
+bool base64_decode(const gsl::cstring_span<> &input, std::string &output) 
+{
+  static const char nop = -1;
+  static const char decoding_data[] = {
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, 62,  nop,
+      nop, nop, 63,  52,  53,  54,  55,  56,  57,  58,  59,  60,  61,  nop, nop,
+      nop, nop, nop, nop, nop, 0,   1,   2,   3,   4,   5,   6,   7,   8,   9,
+      10,  11,  12,  13,  14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,
+      25,  nop, nop, nop, nop, nop, nop, 26,  27,  28,  29,  30,  31,  32,  33,
+      34,  35,  36,  37,  38,  39,  40,  41,  42,  43,  44,  45,  46,  47,  48,
+      49,  50,  51,  nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop, nop,
+      nop};
+
+  unsigned int input_length = input.size();
+
+  // allocate space for output string
+  output.clear();
+  output.reserve(((input_length + 2) / 3) * 4);
+
+  // for each 4-bytes sequence from the input, extract 4 6-bits sequences by
+  // droping first two bits
+  // and regenerate into 3 8-bits sequence
+
+  for (unsigned int i = 0; i < input_length; i++) {
+    char base64code0;
+    char base64code1;
+    char base64code2 = 0; // initialized to 0 to suppress warnings
+    char base64code3;
+
+    base64code0 = decoding_data[static_cast<int>(input[i])];
+    if (base64code0 == nop) // non base64 character
+      return false;
+    if (!(++i < input_length)) // we need at least two input bytes for first
+                               // byte output
+      return false;
+    base64code1 = decoding_data[static_cast<int>(input[i])];
+    if (base64code1 == nop) // non base64 character
+      return false;
+
+    output += ((base64code0 << 2) | ((base64code1 >> 4) & 0x3));
+
+    if (++i < input_length) {
+      char c = input[i];
+      if (c == '=') { // padding , end of input
+        assert((base64code1 & 0x0f) == 0);
+        return true;
+      }
+      base64code2 = decoding_data[static_cast<int>(input[i])];
+      if (base64code2 == nop) // non base64 character
+        return false;
+
+      output += ((base64code1 << 4) & 0xf0) | ((base64code2 >> 2) & 0x0f);
+    }
+
+    if (++i < input_length) {
+      char c = input[i];
+      if (c == '=') { // padding , end of input
+        assert((base64code2 & 0x03) == 0);
+        return true;
+      }
+      base64code3 = decoding_data[static_cast<int>(input[i])];
+      if (base64code3 == nop) // non base64 character
+        return false;
+
+      output += (((base64code2 << 6) & 0xc0) | base64code3);
+    }
+  }
+
+  return true;
+}
+
+}
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