## table of contents

BF_ENCRYPT(3SSL) | OpenSSL | BF_ENCRYPT(3SSL) |

# NAME¶

BF_set_key, BF_encrypt, BF_decrypt, BF_ecb_encrypt, BF_cbc_encrypt, BF_cfb64_encrypt, BF_ofb64_encrypt, BF_options - Blowfish encryption# SYNOPSIS¶

#include <openssl/blowfish.h> void BF_set_key(BF_KEY *key, int len, const unsigned char *data); void BF_ecb_encrypt(const unsigned char *in, unsigned char *out, BF_KEY *key, int enc); void BF_cbc_encrypt(const unsigned char *in, unsigned char *out, long length, BF_KEY *schedule, unsigned char *ivec, int enc); void BF_cfb64_encrypt(const unsigned char *in, unsigned char *out, long length, BF_KEY *schedule, unsigned char *ivec, int *num, int enc); void BF_ofb64_encrypt(const unsigned char *in, unsigned char *out, long length, BF_KEY *schedule, unsigned char *ivec, int *num); const char *BF_options(void); void BF_encrypt(BF_LONG *data, const BF_KEY *key); void BF_decrypt(BF_LONG *data, const BF_KEY *key);

# DESCRIPTION¶

This library implements the Blowfish cipher, which was invented and described by Counterpane (see http://www.counterpane.com/blowfish.html ).Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data. It uses a variable size key, but typically, 128 bit (16 byte) keys are considered good for strong encryption. Blowfish can be used in the same modes as DES (see des_modes(7)). Blowfish is currently one of the faster block ciphers. It is quite a bit faster than DES, and much faster than IDEA or RC2.

Blowfish consists of a key setup phase and the actual encryption or decryption phase.

**BF_set_key()** sets up the **BF_KEY** **key** using the
**len** bytes long key at **data**.

**BF_ecb_encrypt()** is the basic Blowfish encryption and
decryption function. It encrypts or decrypts the first 64 bits of **in**
using the key **key**, putting the result in **out**. **enc**
decides if encryption (**BF_ENCRYPT**) or decryption (**BF_DECRYPT**)
shall be performed. The vector pointed at by **in** and **out** must
be 64 bits in length, no less. If they are larger, everything after the
first 64 bits is ignored.

The mode functions **BF_cbc_encrypt()**,
**BF_cfb64_encrypt()** and **BF_ofb64_encrypt()** all operate on
variable length data. They all take an initialization vector **ivec**
which needs to be passed along into the next call of the same function for
the same message. **ivec** may be initialized with anything, but the
recipient needs to know what it was initialized with, or it won't be able to
decrypt. Some programs and protocols simplify this, like SSH, where
**ivec** is simply initialized to zero. **BF_cbc_encrypt()** operates
on data that is a multiple of 8 bytes long, while **BF_cfb64_encrypt()**
and **BF_ofb64_encrypt()** are used to encrypt an variable number of
bytes (the amount does not have to be an exact multiple of 8). The purpose
of the latter two is to simulate stream ciphers, and therefore, they need
the parameter **num**, which is a pointer to an integer where the current
offset in **ivec** is stored between calls. This integer must be
initialized to zero when **ivec** is initialized.

**BF_cbc_encrypt()** is the Cipher Block Chaining function for
Blowfish. It encrypts or decrypts the 64 bits chunks of **in** using the
key **schedule**, putting the result in **out**. **enc** decides if
encryption (BF_ENCRYPT) or decryption (BF_DECRYPT) shall be performed.
**ivec** must point at an 8 byte long initialization vector.

**BF_cfb64_encrypt()** is the CFB mode for Blowfish with 64 bit
feedback. It encrypts or decrypts the bytes in **in** using the key
**schedule**, putting the result in **out**. **enc** decides if
encryption (**BF_ENCRYPT**) or decryption (**BF_DECRYPT**) shall be
performed. **ivec** must point at an 8 byte long initialization vector.
**num** must point at an integer which must be initially zero.

**BF_ofb64_encrypt()** is the OFB mode for Blowfish with 64 bit
feedback. It uses the same parameters as **BF_cfb64_encrypt()**, which
must be initialized the same way.

**BF_encrypt()** and **BF_decrypt()** are the lowest level
functions for Blowfish encryption. They encrypt/decrypt the first 64 bits of
the vector pointed by **data**, using the key **key**. These functions
should not be used unless you implement 'modes' of Blowfish. The alternative
is to use **BF_ecb_encrypt()**. If you still want to use these functions,
you should be aware that they take each 32-bit chunk in host-byte order,
which is little-endian on little-endian platforms and big-endian on
big-endian ones.

# RETURN VALUES¶

None of the functions presented here return any value.# NOTE¶

Applications should use the higher level functions EVP_EncryptInit(3) etc. instead of calling these functions directly.# SEE ALSO¶

EVP_EncryptInit(3), des_modes(7)# COPYRIGHT¶

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

2019-05-30 | 1.1.1c |