Decryption and Encryption

rand()

Generates a random number, returns an integer value between 0 and RAND_MAX(2^31-1).

Example

when HTTP_REQUEST {
    local rand_num = rand()
    debug("rand_num=%d\n",rand_num)
}

time()

Returns the current time as an integer, in Unix time format.

Example

when HTTP_REQUEST {
    local now = time()
    debug("time now = %d\n", now)
}

time_ms()

Returns the current time in million seconds, in Unix time format

Example

when HTTP_REQUEST {
    local now_ms = time_ms()
    debug("time now in million seconds = %d\n", now_ms)
}

ctime()

Returns the current time as a string, For instance Thu Apr 15 09:01:46 2024 CST +0800

Example

when HTTP_REQUEST {
    local now_str = ctime()
    debug("time now in string format:  %s\n", now_str)
}

md5(input_msg)

Calculates the MD5 hash of a given string input and returns the result as a string.

Example

The following is a helper function to convert byte string into hex representation.

function bytes2hex(bytestr)
    local hexString = ""
    for i = 1, string.len(bytestr) do
        hexString = hexString .. string.format("%02x", string.byte(bytestr, i))
    end
    return hexString
end
when HTTP_REQUEST {
    local md5_encrypted = md5_str("123")
    debug("length of md5_encrypted is %d \n", string.len(md5_encrypted))
    debug("encrypted md5 of string 123 is:  %s\n", bytes2hex(md5_encrypted))
}

md5_hex_str(input_msg)

Calculates the hex representation of the MD5 of a string, and returns the result as a string.

Example

when HTTP_REQUEST {
    local md5_encrypted_hex = md5_hex_str("123")
    debug("encrypted md5 of string 123 in hex representation is:  %s\n", md5_encrypted_hex)
}

sha1_str(input_msg)

Calculates the SHA1 of a string input, and returns the result as a string.

Example

The following is a helper function to convert byte string into hex representation.

function bytes2hex(bytestr)
    local hexString = ""
    for i = 1, string.len(bytestr) do
        hexString = hexString .. string.format("%02x", string.byte(bytestr, i))
    end
    return hexString
end
when HTTP_REQUEST {
    local sha1_123 = sha1_str("123")
    debug("length of sha1_123 is %d \n", string.len(sha1_123))
    debug("encrypted sha1 of string 123  is:  %s\n", bytes2hex(sha1_123))
}

sha1_123_hex(input_msg)

Calculates the hex representation of SHA1 of a string input, and returns the result as a string.

Example

when HTTP_REQUEST {
    local sha1_123_hex = sha1_hex_str("123")
    debug("encrypted sha1 of string 123 in hex representation is:  %s\n", sha1_123_hex)
}

sha256_str(input_msg)

Calculates the SHA256 of a string input, and returns the result as a string.

Example

The following is a helper function to convert byte string into hex representation.

function bytes2hex(bytestr)
    local hexString = ""
    for i = 1, string.len(bytestr) do
        hexString = hexString .. string.format("%02x", string.byte(bytestr, i))
    end
    return hexString
end
when HTTP_REQUEST {
    local sha256_123 = sha256_str("123")
    debug("length of sha256_123 is %d \n", string.len(sha256_123))
    debug("encrypted sha256 of string 123  is:  %s\n", bytes2hex(sha256_123))
}

sha256_hex_str(input_msg)

Calculates the hex representation of SHA1 of a string input, and return the result as a string.

Example

when HTTP_REQUEST {
    local sha256_123_hex = sha256_hex_str("123")
    debug("encrypted sha256 of string 123 in hex representation is:  %s\n", sha256_123_hex)
}

sha512_123(input_msg)

Calculates the SHA512 of a string input, and returns the result as a string.

Example

The following is a helper function to convert byte string into hex representation.

function bytes2hex(bytestr)
    local hexString = ""
    for i = 1, string.len(bytestr) do
        hexString = hexString .. string.format("%02x", string.byte(bytestr, i))
    end
    return hexString
end
when HTTP_REQUEST {
    local sha512_123 = sha512_str("123")
    debug("length of sha512_123 is %d \n", string.len(sha512_123))
    debug("encrypted sha512 of string 123  is:  %s\n", bytes2hex(sha512_123))
}

sha512_123_hex(input_msg)

Calculates the hex representation of SHA1 of a string input, and returns the result in string representation.

Example

when HTTP_REQUEST {
    local sha512_123_hex = sha512_hex_str("123")
    debug("encrypted sha512 of string 123 in hex representation is:  %s\n", sha512_123_hex)
}

base64_enc(input_msg)

Encodes a string input in base64 and outputs the results in string format.

Example

when HTTP_REQUEST {
    local b64_msg = base64_enc("https://www.base64encode.org/")
    debug("base64 encoded message is:  %s\n", b64_msg)
}

base64_dec(input_msg)

Decodes a base64 encoded string input and outputs the results in string format.

Example

when HTTP_REQUEST {
    local b64_dec_msg = base64_dec(b64_msg)
    debug("base64 decoded message is:  %s\n", b64_dec_msg)
}

base32_enc(input_msg)

Encodes a string input in base32 and outputs the results in string format.

Example

when HTTP_REQUEST {
    local b32_msg = base32_enc("https://www.base64encode.org/")
    debug("base32 encoded message is:  %s\n", b32_msg)
}

base32_dec(input_msg)

Decodes a base32 encoded string input and outputs the results in string format.

Example

when HTTP_REQUEST {
    local b32_dec_msg = base32_dec(b32_msg)
    debug("base32 decoded message is:  %s\n", b32_dec_msg)
}

htonl(input_msg)

Converts a long integer input into network byte order.

Example

when HTTP_REQUEST {
    local network_a  = htonl(32)
    debug("htonl of 32 is:  %s\n", network_a)
}

htons(input_msg)

Converts a short integer input into network byte order.

Example

when HTTP_REQUEST {
local network_a_short  = htons(32)
debug("htons of 32 is:  %s\n", network_a_short)
}

htons(input_msg)

Converts a long integer input into host byte order. Keep in mind, htonl(ntohl(x)) == x.

Example

when HTTP_REQUEST {
    local host_a = ntohl(network_a)
    debug("ntohl of network_a is:  %s\n", host_a)
}

host_a_short(input_msg)

Converts a short integer input into host byte order.

Example

when HTTP_REQUEST {
    local host_a_short = ntohs(network_a_short)
    debug("ntohs of network_a_short is:  %s\n", host_a_short)
}

to_hex(input_msg)

Converts a string to its hex representation.

Example

when HTTP_REQUEST {
    local hexit = to_hex("it")
    debug("hexit is:  %s\n", hexit)
}

crc32(input_msg)

Returns the crc32 check value of the string, return value is the crc32 code.

Example

when HTTP_REQUEST {
    local crc32_code = crc32("123456789")
    debug("CRC 32 code is:  %d\n", crc32_code)
}

key_gen(pass, salt, iter, key_len)

Derives an AES key from a password using a salt and iteration count as specified in RFC 2898 (Password-Based Key Derivation Function 2 with HMAC-SHA256).

Example

The following is a helper function to convert byte string into hex representation.

function bytes2hex(bytestr)
    local hexString = ""
    for i = 1, string.len(bytestr) do
       hexString = hexString .. string.format("%02x", string.byte(bytestr, i))
    end
    return hexString
end
when HTTP_REQUEST {
    local new_key = key_gen("pass", "salt", 32, 32)
    debug("new key is %s\n", bytes2hex(new_key))
}

aes_enc("your message", "paste your key here", Key Size)

Encrypts a string using AES algorithm.

Example

The following is a helper function to convert byte string into hex representation.

when HTTP_REQUEST {
    local aes_encrypted = aes_enc("your message", "paste your key here", 128)
    debug("encrypted in hex is %s, after b64 encoding %s\n", to_hex(aes_encrypted), base64_enc(aes_encrypted))
}

aes_decrypted("your message", "paste your key here", Key Size)

Decrypt a string using AES algorithm.

Example

when HTTP_REQUEST {
    local aes_decrypted = aes_dec(aes_encrypted, "paste your key here", 128);
    debug("decrypted msg is %s\n", aes_decrypted)
}

EVP_Digest(alg, str)

EVP_Digest(alg, str) EVP_Digest for one-shot digest calculation.

Example

when HTTP_REQUEST {
    local evpd = EVP_Digest("MD5", "your data")
    debug("the digest in hex is %s\n", bytes2hex(evpd))
}

HMAC(alg, "your data", "paste your key here")

HMAC message authentication code.

Example

when HTTP_REQUEST {
    local hm = HMAC("SHA256", "your data", "paste your key here")
    debug("the HMAC in hex is %s\n", bytes2hex(hm))
}

HMAC_verify(alg, msg, key, verify)

Checks if the signature is same as the current digest.

Example

when HTTP_REQUEST {
    local is_same = HMAC_verify("SHA256", "your data", "paste your key here", hm)
    if is_same then
        debug("HMAC verified\n")
    else
        debug("HMAC not verified\n")
    end
}

rand_hex(input)

Generates a random number in HEX.

Example

when HTTP_REQUEST {
    local rand_h = rand_hex(16);
    debug("the random hex number  is %s\n", rand_h);
}

rand_alphanum(input)

Generates a random alphabet+number sequence.

Example

when HTTP_REQUEST {
    local alphanumber = rand_alphanum(16);
    debug("the alphabet+number sequence  is %s\n", alphanumber);
}

rand_seq(input)

Generates a random number sequence.

Example

when HTTP_REQUEST {
    local randseq = rand_seq(16);
    debug("the random sequence is %s\n", to_hex(randseq));
}

url_encode(input)

Encodes the target URL (Converts URL into a valid ASCII format, will not replace space by "+" sign).

Example

when HTTP_REQUEST {
    local encoded_url = url_encode("https://docs.fortinet.com/product/fortiweb/7.4");
    debug("the encoded url is %s\n", encoded_url);
}

url_decode(input)

Decodes the encoding-URL into its original URL.

Example

when HTTP_REQUEST {
    local decoded_url = url_decode(encoded_url);
    debug("the decoded url is %s\n", decoded_url);
}