-int writeBase64 (unsigned char *, size_t, unsigned char *);
-int writeBase64raw (unsigned char *, size_t, unsigned char *);
+int writeBase64 (const unsigned char *, size_t, unsigned char *);
+int writeBase64raw (const unsigned char *, size_t, unsigned char *);
+
+/*
+ * encoded - the string to be decoded
+ * decoded - the decoded bytes
+ * len - number of decoded bytes
+ * skip-crs - non-zero for text content, and for which CR's should be
+ * skipped
+ * digest - for an MD5 digest, it can be null
+ */
+int decodeBase64 (const char *encoded, unsigned char **decoded, size_t *len,
+ int skip_crs, unsigned char *digest);
+
+void hexify (const unsigned char *, size_t, char **);