diff --git a/src/borg/crypto/low_level.pyx b/src/borg/crypto/low_level.pyx
index 6db9778009..da06c73e20 100644
--- a/src/borg/crypto/low_level.pyx
+++ b/src/borg/crypto/low_level.pyx
@@ -134,25 +134,12 @@ import struct
 
 _int = struct.Struct('>I')
 _long = struct.Struct('>Q')
-_2long = struct.Struct('>QQ')
 
 bytes_to_int = lambda x, offset=0: _int.unpack_from(x, offset)[0]
 bytes_to_long = lambda x, offset=0: _long.unpack_from(x, offset)[0]
 long_to_bytes = lambda x: _long.pack(x)
 
 
-def bytes16_to_int(b, offset=0):
-    h, l = _2long.unpack_from(b, offset)
-    return (h << 64) + l
-
-
-def int_to_bytes16(i):
-    max_uint64 = 0xffffffffffffffff
-    l = i & max_uint64
-    h = (i >> 64) & max_uint64
-    return _2long.pack(h, l)
-
-
 def num_cipher_blocks(length, blocksize=16):
     """Return the number of cipher blocks required to encrypt/decrypt <length> bytes of data.
 
diff --git a/src/borg/selftest.py b/src/borg/selftest.py
index 619edb8fea..e8605f7cb3 100644
--- a/src/borg/selftest.py
+++ b/src/borg/selftest.py
@@ -30,7 +30,7 @@
     ChunkerTestCase,
 ]
 
-SELFTEST_COUNT = 38
+SELFTEST_COUNT = 37
 
 
 class SelfTestResult(TestResult):
diff --git a/src/borg/testsuite/crypto.py b/src/borg/testsuite/crypto.py
index a60ab2fb3a..a4e822c5df 100644
--- a/src/borg/testsuite/crypto.py
+++ b/src/borg/testsuite/crypto.py
@@ -2,7 +2,7 @@
 
 from ..crypto.low_level import AES256_CTR_HMAC_SHA256, AES256_GCM, AES256_OCB, CHACHA20_POLY1305, UNENCRYPTED, \
                                IntegrityError, blake2b_256, hmac_sha256, openssl10
-from ..crypto.low_level import bytes_to_long, bytes_to_int, long_to_bytes, bytes16_to_int, int_to_bytes16
+from ..crypto.low_level import bytes_to_long, bytes_to_int, long_to_bytes
 from ..crypto.low_level import hkdf_hmac_sha512
 
 from . import BaseTestCase
@@ -20,12 +20,6 @@ def test_bytes_to_long(self):
         self.assert_equal(bytes_to_long(b'\0\0\0\0\0\0\0\1'), 1)
         self.assert_equal(long_to_bytes(1), b'\0\0\0\0\0\0\0\1')
 
-    def test_bytes16_to_int(self):
-        self.assert_equal(bytes16_to_int(b'\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1'), 1)
-        self.assert_equal(int_to_bytes16(1), b'\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1')
-        self.assert_equal(bytes16_to_int(b'\0\0\0\0\0\0\0\1\0\0\0\0\0\0\0\0'), 2 ** 64)
-        self.assert_equal(int_to_bytes16(2 ** 64), b'\0\0\0\0\0\0\0\1\0\0\0\0\0\0\0\0')
-
     def test_UNENCRYPTED(self):
         iv = b''  # any IV is ok, it just must be set and not None
         data = b'data'