Commit 8d41e6c4 authored by Nick Mathewson's avatar Nick Mathewson 🦀
Browse files

Support for encoding and decoding 256-bit digests in base64

parent 5ef97ddd

src/common/crypto.c

+38 −0
Original line number Diff line number Diff line
@@ -2274,6 +2274,44 @@ digest_from_base64(char *digest, const char *d64) 
#endif

}



/** Base-64 encode DIGEST256_LINE bytes from <b>digest</b>, remove the

 * trailing = and newline characters, and store the nul-terminated result in

 * the first BASE64_DIGEST256_LEN+1 bytes of <b>d64</b>.  */

int

digest256_to_base64(char *d64, const char *digest)

{

  char buf[256];

  base64_encode(buf, sizeof(buf), digest, DIGEST256_LEN);

  buf[BASE64_DIGEST256_LEN] = '\0';

  memcpy(d64, buf, BASE64_DIGEST256_LEN+1);

  return 0;

}



/** Given a base-64 encoded, nul-terminated digest in <b>d64</b> (without

 * trailing newline or = characters), decode it and store the result in the

 * first DIGEST256_LEN bytes at <b>digest</b>. */

int

digest256_from_base64(char *digest, const char *d64)

{

#ifdef USE_OPENSSL_BASE64

  char buf_in[BASE64_DIGEST256_LEN+3];

  char buf[256];

  if (strlen(d64) != BASE64_DIGEST256_LEN)

    return -1;

  memcpy(buf_in, d64, BASE64_DIGEST256_LEN);

  memcpy(buf_in+BASE64_DIGEST256_LEN, "=\n\0", 3);

  if (base64_decode(buf, sizeof(buf), buf_in, strlen(buf_in)) != DIGEST256_LEN)

    return -1;

  memcpy(digest, buf, DIGEST256_LEN);

  return 0;

#else

  if (base64_decode(digest, DIGEST256_LEN, d64, strlen(d64)) == DIGEST256_LEN)

    return 0;

  else

    return -1;

#endif

}



/** Implements base32 encoding as in rfc3548.  Limitation: Requires

 * that srclen*8 is a multiple of 5.

 */

src/common/crypto.h

+2 −0
Original line number Diff line number Diff line
@@ -211,6 +211,8 @@ int base32_decode(char *dest, size_t destlen, const char *src, size_t srclen); 


int digest_to_base64(char *d64, const char *digest);

int digest_from_base64(char *digest, const char *d64);

int digest256_to_base64(char *d64, const char *digest);

int digest256_from_base64(char *digest, const char *d64);



/** Length of RFC2440-style S2K specifier: the first 8 bytes are a salt, the

 * 9th describes how much iteration to do. */

src/test/test_crypto.c

+11 −0
Original line number Diff line number Diff line
@@ -472,6 +472,17 @@ test_crypto_formats(void) 


  test_assert(digest_from_base64(data3, "###") < 0);



  /* Encoding SHA256 */

  crypto_rand(data2, DIGEST256_LEN);

  memset(data2, 100, 1024);

  digest256_to_base64(data2, data1);

  test_eq(BASE64_DIGEST256_LEN, strlen(data2));

  test_eq(100, data2[BASE64_DIGEST256_LEN+2]);

  memset(data3, 99, 1024);

  test_eq(digest256_from_base64(data3, data2), 0);

  test_memeq(data1, data3, DIGEST256_LEN);

  test_eq(99, data3[DIGEST256_LEN+1]);



  /* Base32 tests */

  strlcpy(data1, "5chrs", 1024);

  /* bit pattern is:  [35 63 68 72 73] ->