diff --git a/decrepit/CMakeLists.txt b/decrepit/CMakeLists.txt
index b43fea7..a486c1b 100644
--- a/decrepit/CMakeLists.txt
+++ b/decrepit/CMakeLists.txt
@@ -1,9 +1,11 @@
 add_subdirectory(cast)
 add_subdirectory(blowfish)
+add_subdirectory(bio)
 
 add_library(
   decrepit
 
-  $<TARGET_OBJECTS:cast>
+  $<TARGET_OBJECTS:bio_decrepit>
   $<TARGET_OBJECTS:blowfish>
+  $<TARGET_OBJECTS:cast>
 )
diff --git a/decrepit/bio/CMakeLists.txt b/decrepit/bio/CMakeLists.txt
new file mode 100644
index 0000000..3da5e5c
--- /dev/null
+++ b/decrepit/bio/CMakeLists.txt
@@ -0,0 +1,9 @@
+include_directories(. ../../include)
+
+add_library(
+  bio_decrepit
+
+  OBJECT
+
+  base64_bio.c
+)
diff --git a/decrepit/bio/base64_bio.c b/decrepit/bio/base64_bio.c
new file mode 100644
index 0000000..2056138
--- /dev/null
+++ b/decrepit/bio/base64_bio.c
@@ -0,0 +1,536 @@
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.] */
+
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <openssl/base64.h>
+#include <openssl/bio.h>
+#include <openssl/buffer.h>
+#include <openssl/evp.h>
+#include <openssl/mem.h>
+
+
+#define B64_BLOCK_SIZE 1024
+#define B64_BLOCK_SIZE2 768
+#define B64_NONE 0
+#define B64_ENCODE 1
+#define B64_DECODE 2
+#define EVP_ENCODE_LENGTH(l) (((l+2)/3*4)+(l/48+1)*2+80)
+
+typedef struct b64_struct {
+  int buf_len;
+  int buf_off;
+  int tmp_len; /* used to find the start when decoding */
+  int tmp_nl;  /* If true, scan until '\n' */
+  int encode;
+  int start; /* have we started decoding yet? */
+  int cont;  /* <= 0 when finished */
+  EVP_ENCODE_CTX base64;
+  char buf[EVP_ENCODE_LENGTH(B64_BLOCK_SIZE) + 10];
+  char tmp[B64_BLOCK_SIZE];
+} BIO_B64_CTX;
+
+static int b64_new(BIO *bio) {
+  BIO_B64_CTX *ctx;
+
+  ctx = OPENSSL_malloc(sizeof(*ctx));
+  if (ctx == NULL) {
+    return 0;
+  }
+
+  memset(ctx, 0, sizeof(*ctx));
+
+  ctx->cont = 1;
+  ctx->start = 1;
+
+  bio->init = 1;
+  bio->ptr = (char *)ctx;
+  return 1;
+}
+
+static int b64_free(BIO *bio) {
+  if (bio == NULL) {
+    return 0;
+  }
+  OPENSSL_free(bio->ptr);
+  bio->ptr = NULL;
+  bio->init = 0;
+  bio->flags = 0;
+  return 1;
+}
+
+static int b64_read(BIO *b, char *out, int outl) {
+  int ret = 0, i, ii, j, k, x, n, num, ret_code = 0;
+  BIO_B64_CTX *ctx;
+  uint8_t *p, *q;
+
+  if (out == NULL) {
+    return 0;
+  }
+  ctx = (BIO_B64_CTX *) b->ptr;
+
+  if (ctx == NULL || b->next_bio == NULL) {
+    return 0;
+  }
+
+  BIO_clear_retry_flags(b);
+
+  if (ctx->encode != B64_DECODE) {
+    ctx->encode = B64_DECODE;
+    ctx->buf_len = 0;
+    ctx->buf_off = 0;
+    ctx->tmp_len = 0;
+    EVP_DecodeInit(&ctx->base64);
+  }
+
+  /* First check if there are bytes decoded/encoded */
+  if (ctx->buf_len > 0) {
+    assert(ctx->buf_len >= ctx->buf_off);
+    i = ctx->buf_len - ctx->buf_off;
+    if (i > outl) {
+      i = outl;
+    }
+    assert(ctx->buf_off + i < (int)sizeof(ctx->buf));
+    memcpy(out, &ctx->buf[ctx->buf_off], i);
+    ret = i;
+    out += i;
+    outl -= i;
+    ctx->buf_off += i;
+    if (ctx->buf_len == ctx->buf_off) {
+      ctx->buf_len = 0;
+      ctx->buf_off = 0;
+    }
+  }
+
+  /* At this point, we have room of outl bytes and an empty buffer, so we
+   * should read in some more. */
+
+  ret_code = 0;
+  while (outl > 0) {
+    if (ctx->cont <= 0) {
+      break;
+    }
+
+    i = BIO_read(b->next_bio, &(ctx->tmp[ctx->tmp_len]),
+                 B64_BLOCK_SIZE - ctx->tmp_len);
+
+    if (i <= 0) {
+      ret_code = i;
+
+      /* Should we continue next time we are called? */
+      if (!BIO_should_retry(b->next_bio)) {
+        ctx->cont = i;
+        /* If buffer empty break */
+        if (ctx->tmp_len == 0) {
+          break;
+        } else {
+          /* Fall through and process what we have */
+          i = 0;
+        }
+      } else {
+        /* else we retry and add more data to buffer */
+        break;
+      }
+    }
+    i += ctx->tmp_len;
+    ctx->tmp_len = i;
+
+    /* We need to scan, a line at a time until we have a valid line if we are
+     * starting. */
+    if (ctx->start && (BIO_test_flags(b, BIO_FLAGS_BASE64_NO_NL))) {
+      /* ctx->start = 1; */
+      ctx->tmp_len = 0;
+    } else if (ctx->start) {
+      q = p = (uint8_t *)ctx->tmp;
+      num = 0;
+      for (j = 0; j < i; j++) {
+        if (*(q++) != '\n') {
+          continue;
+        }
+
+        /* due to a previous very long line, we need to keep on scanning for a
+         * '\n' before we even start looking for base64 encoded stuff. */
+        if (ctx->tmp_nl) {
+          p = q;
+          ctx->tmp_nl = 0;
+          continue;
+        }
+
+        k = EVP_DecodeUpdate(&(ctx->base64), (uint8_t *)ctx->buf, &num, p,
+                             q - p);
+
+        if (k <= 0 && num == 0 && ctx->start) {
+          EVP_DecodeInit(&ctx->base64);
+        } else {
+          if (p != (uint8_t *)&(ctx->tmp[0])) {
+            i -= (p - (uint8_t *)&(ctx->tmp[0]));
+            for (x = 0; x < i; x++) {
+              ctx->tmp[x] = p[x];
+            }
+          }
+          EVP_DecodeInit(&ctx->base64);
+          ctx->start = 0;
+          break;
+        }
+        p = q;
+      }
+
+      /* we fell off the end without starting */
+      if (j == i && num == 0) {
+        /* Is this is one long chunk?, if so, keep on reading until a new
+         * line. */
+        if (p == (uint8_t *)&(ctx->tmp[0])) {
+          /* Check buffer full */
+          if (i == B64_BLOCK_SIZE) {
+            ctx->tmp_nl = 1;
+            ctx->tmp_len = 0;
+          }
+        } else if (p != q) { /* finished on a '\n' */
+          n = q - p;
+          for (ii = 0; ii < n; ii++) {
+            ctx->tmp[ii] = p[ii];
+          }
+          ctx->tmp_len = n;
+        }
+        /* else finished on a '\n' */
+        continue;
+      } else {
+        ctx->tmp_len = 0;
+      }
+    } else if (i < B64_BLOCK_SIZE && ctx->cont > 0) {
+      /* If buffer isn't full and we can retry then restart to read in more
+       * data. */
+      continue;
+    }
+
+    if (BIO_test_flags(b, BIO_FLAGS_BASE64_NO_NL)) {
+      int z, jj;
+
+      jj = i & ~3; /* process per 4 */
+      z = EVP_DecodeBlock((uint8_t *)ctx->buf, (uint8_t *)ctx->tmp, jj);
+      if (jj > 2) {
+        if (ctx->tmp[jj - 1] == '=') {
+          z--;
+          if (ctx->tmp[jj - 2] == '=') {
+            z--;
+          }
+        }
+      }
+      /* z is now number of output bytes and jj is the number consumed. */
+      if (jj != i) {
+        memmove(ctx->tmp, &ctx->tmp[jj], i - jj);
+        ctx->tmp_len = i - jj;
+      }
+      ctx->buf_len = 0;
+      if (z > 0) {
+        ctx->buf_len = z;
+      }
+      i = z;
+    } else {
+      i = EVP_DecodeUpdate(&(ctx->base64), (uint8_t *)ctx->buf,
+                           &ctx->buf_len, (uint8_t *)ctx->tmp, i);
+      ctx->tmp_len = 0;
+    }
+    ctx->buf_off = 0;
+    if (i < 0) {
+      ret_code = 0;
+      ctx->buf_len = 0;
+      break;
+    }
+
+    if (ctx->buf_len <= outl) {
+      i = ctx->buf_len;
+    } else {
+      i = outl;
+    }
+
+    memcpy(out, ctx->buf, i);
+    ret += i;
+    ctx->buf_off = i;
+    if (ctx->buf_off == ctx->buf_len) {
+      ctx->buf_len = 0;
+      ctx->buf_off = 0;
+    }
+    outl -= i;
+    out += i;
+  }
+
+  BIO_copy_next_retry(b);
+  return ret == 0 ? ret_code : ret;
+}
+
+static int b64_write(BIO *b, const char *in, int inl) {
+  int ret = 0, n, i;
+  BIO_B64_CTX *ctx;
+
+  ctx = (BIO_B64_CTX *)b->ptr;
+  BIO_clear_retry_flags(b);
+
+  if (ctx->encode != B64_ENCODE) {
+    ctx->encode = B64_ENCODE;
+    ctx->buf_len = 0;
+    ctx->buf_off = 0;
+    ctx->tmp_len = 0;
+    EVP_EncodeInit(&(ctx->base64));
+  }
+
+  assert(ctx->buf_off < (int)sizeof(ctx->buf));
+  assert(ctx->buf_len <= (int)sizeof(ctx->buf));
+  assert(ctx->buf_len >= ctx->buf_off);
+
+  n = ctx->buf_len - ctx->buf_off;
+  while (n > 0) {
+    i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
+    if (i <= 0) {
+      BIO_copy_next_retry(b);
+      return i;
+    }
+    assert(i <= n);
+    ctx->buf_off += i;
+    assert(ctx->buf_off <= (int)sizeof(ctx->buf));
+    assert(ctx->buf_len >= ctx->buf_off);
+    n -= i;
+  }
+
+  /* at this point all pending data has been written. */
+  ctx->buf_off = 0;
+  ctx->buf_len = 0;
+
+  if (in == NULL || inl <= 0) {
+    return 0;
+  }
+
+  while (inl > 0) {
+    n = (inl > B64_BLOCK_SIZE) ? B64_BLOCK_SIZE : inl;
+
+    if (BIO_test_flags(b, BIO_FLAGS_BASE64_NO_NL)) {
+      if (ctx->tmp_len > 0) {
+        assert(ctx->tmp_len <= 3);
+        n = 3 - ctx->tmp_len;
+        /* There's a theoretical possibility of this. */
+        if (n > inl) {
+          n = inl;
+        }
+        memcpy(&(ctx->tmp[ctx->tmp_len]), in, n);
+        ctx->tmp_len += n;
+        ret += n;
+        if (ctx->tmp_len < 3) {
+          break;
+        }
+        ctx->buf_len = EVP_EncodeBlock((uint8_t *)ctx->buf, (uint8_t *)ctx->tmp,
+                                       ctx->tmp_len);
+        assert(ctx->buf_len <= (int)sizeof(ctx->buf));
+        assert(ctx->buf_len >= ctx->buf_off);
+
+        /* Since we're now done using the temporary buffer, the length should
+         * be zeroed. */
+        ctx->tmp_len = 0;
+      } else {
+        if (n < 3) {
+          memcpy(ctx->tmp, in, n);
+          ctx->tmp_len = n;
+          ret += n;
+          break;
+        }
+        n -= n % 3;
+        ctx->buf_len =
+            EVP_EncodeBlock((uint8_t *)ctx->buf, (const uint8_t *)in, n);
+        assert(ctx->buf_len <= (int)sizeof(ctx->buf));
+        assert(ctx->buf_len >= ctx->buf_off);
+        ret += n;
+      }
+    } else {
+      EVP_EncodeUpdate(&(ctx->base64), (uint8_t *)ctx->buf, &ctx->buf_len,
+                       (uint8_t *)in, n);
+      assert(ctx->buf_len <= (int)sizeof(ctx->buf));
+      assert(ctx->buf_len >= ctx->buf_off);
+      ret += n;
+    }
+    inl -= n;
+    in += n;
+
+    ctx->buf_off = 0;
+    n = ctx->buf_len;
+
+    while (n > 0) {
+      i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
+      if (i <= 0) {
+        BIO_copy_next_retry(b);
+        return ret == 0 ? i : ret;
+      }
+      assert(i <= n);
+      n -= i;
+      ctx->buf_off += i;
+      assert(ctx->buf_off <= (int)sizeof(ctx->buf));
+      assert(ctx->buf_len >= ctx->buf_off);
+    }
+    ctx->buf_len = 0;
+    ctx->buf_off = 0;
+  }
+  return ret;
+}
+
+static long b64_ctrl(BIO *b, int cmd, long num, void *ptr) {
+  BIO_B64_CTX *ctx;
+  long ret = 1;
+  int i;
+
+  ctx = (BIO_B64_CTX *)b->ptr;
+
+  switch (cmd) {
+    case BIO_CTRL_RESET:
+      ctx->cont = 1;
+      ctx->start = 1;
+      ctx->encode = B64_NONE;
+      ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
+      break;
+
+    case BIO_CTRL_EOF: /* More to read */
+      if (ctx->cont <= 0) {
+        ret = 1;
+      } else {
+        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
+      }
+      break;
+
+    case BIO_CTRL_WPENDING: /* More to write in buffer */
+      assert(ctx->buf_len >= ctx->buf_off);
+      ret = ctx->buf_len - ctx->buf_off;
+      if ((ret == 0) && (ctx->encode != B64_NONE) && (ctx->base64.num != 0)) {
+        ret = 1;
+      } else if (ret <= 0) {
+        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
+      }
+      break;
+
+    case BIO_CTRL_PENDING: /* More to read in buffer */
+      assert(ctx->buf_len >= ctx->buf_off);
+      ret = ctx->buf_len - ctx->buf_off;
+      if (ret <= 0) {
+        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
+      }
+      break;
+
+    case BIO_CTRL_FLUSH:
+    /* do a final write */
+    again:
+      while (ctx->buf_len != ctx->buf_off) {
+        i = b64_write(b, NULL, 0);
+        if (i < 0) {
+          return i;
+        }
+      }
+      if (BIO_test_flags(b, BIO_FLAGS_BASE64_NO_NL)) {
+        if (ctx->tmp_len != 0) {
+          ctx->buf_len = EVP_EncodeBlock((uint8_t *)ctx->buf,
+                                         (uint8_t *)ctx->tmp, ctx->tmp_len);
+          ctx->buf_off = 0;
+          ctx->tmp_len = 0;
+          goto again;
+        }
+      } else if (ctx->encode != B64_NONE && ctx->base64.num != 0) {
+        ctx->buf_off = 0;
+        EVP_EncodeFinal(&(ctx->base64), (uint8_t *)ctx->buf, &(ctx->buf_len));
+        /* push out the bytes */
+        goto again;
+      }
+      /* Finally flush the underlying BIO */
+      ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
+      break;
+
+    case BIO_C_DO_STATE_MACHINE:
+      BIO_clear_retry_flags(b);
+      ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
+      BIO_copy_next_retry(b);
+      break;
+
+    case BIO_CTRL_INFO:
+    case BIO_CTRL_GET:
+    case BIO_CTRL_SET:
+    default:
+      ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
+      break;
+  }
+  return ret;
+}
+
+static long b64_callback_ctrl(BIO *b, int cmd, bio_info_cb fp) {
+  long ret = 1;
+
+  if (b->next_bio == NULL) {
+    return 0;
+  }
+  switch (cmd) {
+    default:
+      ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
+      break;
+  }
+  return ret;
+}
+
+static int b64_puts(BIO *b, const char *str) {
+  return b64_write(b, str, strlen(str));
+}
+
+static const BIO_METHOD b64_method = {
+    BIO_TYPE_BASE64, "base64 encoding", b64_write, b64_read, b64_puts,
+    NULL /* gets */, b64_ctrl,          b64_new,   b64_free, b64_callback_ctrl,
+};
+
+const BIO_METHOD *BIO_f_base64(void) { return &b64_method; }
diff --git a/include/openssl/bio.h b/include/openssl/bio.h
index bb15591..a1ab699 100644
--- a/include/openssl/bio.h
+++ b/include/openssl/bio.h
@@ -727,6 +727,15 @@
 #define BIO_print_errors_fp ERR_print_errors_fp
 
 
+/* Deprecated functions. */
+
+/* Returns a filter |BIO| that base64-encodes data written into it, and decodes
+ * data read from it. |BIO_gets| is not supported. Call |BIO_flush| when done
+ * writing, to signal that no more data are to be encoded. The flag
+ * |BIO_FLAGS_BASE64_NO_NL| may be set to encode all the data on one line. */
+OPENSSL_EXPORT const BIO_METHOD *BIO_f_base64(void);
+
+
 /* Private functions */
 
 #define BIO_FLAGS_READ 0x01