Dear SCO Customer, The enclosed International Crypt Support Level Supplement (SLS) lng225 revision b is for use with SCO UNIX System V/386 and SCO XENIX System V Development Systems. This SLS provides the international version of the crypt(S) library. Note that decryption is not provided in this version of crypt(S). If decryption is attempted an error message is printed. Please see the enclosed manual page for crypt(S) for more details. SLS lng225 will install on machines running: SCO XENIX Operating System Release 2.2 and later; SCO XENIX Development System Release 2.2 and later; SCO UNIX System V/386 Release 3.2 Operating System Version 1.0 and later; SCO UNIX System V/386 Release 3.2 Development System Version 1.0. It includes Small, Medium and Large model OMF format libraries and both OMF and COFF format 386 libraries. To install this SLS lng225 revision b, take the following steps: (1) Reboot your system and enter System Maintenance Mode. (2) Insert the enclosed disk in the primary floppy drive and close the door. (3) If you are installing on SCO XENIX type "/etc/install". If you are installing on SCO UNIX System V/386, type "/etc/xinstall". (4) Follow the instructions on the screen. If you have any further questions please contact your supplier. Yours sincerely, Technical Support Department. ref: lng225 rev b CRYPT(S) UNIX System V CRYPT(S) Name crypt - password and file encryption functions Syntax cc [flag ...] file ... -lcrypt char *crypt (key, salt) char *key, *salt; void setkey (key) char *key; void encrypt (block, flag) char *block; int flag; char *des_crypt (key, salt) char *key, *salt; void des_setkey (key) char *key; void des_encrypt (block, flag) char *block; int flag; int run_setkey (p, key) int p[2]; char *key; int run_crypt (offset, buffer, count, p) long offset; char *buffer; unsigned int count; int p[2]; int crypt_close(p) int p[2]; Description des_crypt is the password encryption function. It is based on a one-way hashing encryption algorithm with variations intended (among other things) to frustrate use of hardware implementations of a key search. key is a user's typed password. salt is a two-character string chosen from the set [a-zA-Z0-9./]. This string is used to perturb the hashing algorithm in one of 4096 different ways, after which the password is used as the key to encrypt repeatedly a constant string. The returned value points to the encrypted password. The first two characters are the salt itself. The des_setkey and des_encrypt entries provide (rather primitive) access to the actual hashing algorithm. The argument of des_setkey is a character array of length 64 containing only the characters with numerical value 0 and 1. If this string is divided into groups of 8, the low-order bit in each group is ignored; this gives a 56-bit key which is set into the machine. This is the key that will be used with the hashing algorithm to encrypt the string block with the function des_encrypt. The argument to the des_encrypt entry is a character array of length 64 containing only the characters with numerical value 0 and 1. The argument array is modified in place to a similar array representing the bits of the argument after having been subjected to the hashing algorithm using the key set by des_setkey. If edflag is zero, the argument is encrypted; if non-zero, it is decrypted. Note that decryption is not provided in the international version of crypt(S). If decryption is attempted with the international version of des_encrypt, an error message is printed. crypt, setkey, and encrypt are front-end routines that invoke des_crypt, des_setkey, and des_encrypt respectively. The routines run_setkey and run_crypt are designed for use by applications that need cryptographic capabilities (such as ed(C) and vi(C)) that must be compatible with the crypt(C) user-level utility. run_setkey establishes a two- way pipe connection with crypt(C), using key as the password argument. run_crypt takes a block of characters and transforms the cleartext or ciphertext using crypt(C). Offset is the relative byte position from the beginning of the file that the block of text provided in block is coming from. count is the number of characters in block, and connection is an array containing indices to a table of input and output file streams. When encryption is finished, crypt_close is used to terminate the connection with crypt(C). run_setkey returns -1 if a connection with crypt(C) cannot be established. This will occur on international versions of the UNIX system where crypt(C) is not available. If a null key is passed to run_setkey, 0 is returned. Otherwise, 1 is returned. run_crypt returns -1 if it cannot write output or read input from the pipe attached to crypt. Otherwise it returns 0. See Also crypt(S), getpass(S), passwd(F), crypt(C), login(M), passwd(C) Diagnostics In the international version of crypt(S), a flag argument of 1 to des_encrypt is not accepted, and an error message is printed. Note The return value in crypt points to static data that are overwritten by each call. Standards Conformance crypt is conformant with: AT&T SVID Issue 2, Select Code 307-127; and The X/Open Portability Guide II of January 1987.