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diff --git a/librecrypt.7 b/librecrypt.7 new file mode 100644 index 0000000..7c577a4 --- /dev/null +++ b/librecrypt.7 @@ -0,0 +1,128 @@ +.TH LIBRECRYPT 7 LIBRECRYPT +.SH NAME +librecrypt - Offline-hardenable password hashing + +.SH SYNOPSIS +.ni +#include <librecrypt.h> +.fi +.PP +Link with +.IR -lrecrypt . +Static linking may require additional +flags depending on enabled hash algorithms. + +.SH DESCRIPTION +The +.B librecrypt +library provides a unified interface for +several password hash functions and the ability to chain +password hash functions so that a weaking hashed password +can be hardend, without knowing the plain-text password, +by hashing the hash with a stronger function. +.PP +.B librecrypt +extends +.BR crypt (3)\(aqs +password hash string syntax +by introducing the +.RB \(aq > \(aq +character to specifying chaining. +The left-most hash function is used on the plain-text +password, and the next to the right, is used on the binary +hash result, and so on, and only the final hash is stored +in the string: as part of the last +.RB \(aq > \(aq-delimited +section. +.PP +It also supports specifying a password hashing configuration +without specifying actual salt values, but instead how many +bytes of salt to generate. This done using asterisk-encoding: +an ASCII asterisk character +.RB (\(aq * \(aq) +followed by the number of +bytes encoded as a non-negative decimal number in ASCII. +.PP +The +.B librecrypt +library implements the following functions: +.sp +.SS Password hashing functions: +.TP +.BR librecrypt_crypt (3) +Compute password hash encoded in ASCII with settings +prefix. +.TP +.BR librecrypt_hash (3) +Compute password hash encoded in ASCII without +settings prefix. +.TP +.BR librecrypt_hash_binary (3) +Compute password hash in raw binary form. +.TP +.BR librecrypt_add_algorithm (3) +Append an algorithm chain to a password hash string. +.sp +.SS Password hashing configuration generation functions: +.TP +.BR librecrypt_test_supported (3) +Check whether an algorithm chain is supported. +.TP +.BR librecrypt_make_settings (3) +Generate a password hash settings string. +.TP +.BR librecrypt_realise_salts (3) +Realise asterisk-encoded random salts in a settings +string. +.sp +.SS Secure application helper functions: +.TP +.BR librecrypt_equal (3) +Compare strings in constant time. +.TP +.BR librecrypt_equal_binary (3) +Compare memory segments in constant time. +.TP +.BR librecrypt_wipe (3) +Securely erase a memory buffer. +.TP +.BR librecrypt_wipe_str (3) +Securely erase a string. +.sp +.SS Password hash string decomposition functions (ADVANCED): +.TP +.BR librecrypt_settings_prefix (3) +Get length of settings prefix in a password hash +string. +.TP +.BR librecrypt_chain_length (3) +Get number of algorithms in a chained password hash +string. +.TP +.BR librecrypt_decompose_chain (3) +Split a chained password hash string into algorithm +components. +.TP +.BR librecrypt_decompose_chain1 (3) +Replace algorithm link delimiters with null bytes. +.TP +.BR librecrypt_next_algorithm (3) +Iterate over algorithms in a chained password hash +string. +.sp +.SS Binary value encoding functions (ADVANCED): +.TP +.BR librecrypt_encode (3) +Encode binary salt or hash result into ASCII. +.TP +.BR librecrypt_decode (3) +Decode ASCII encoding of a salt or hash result into +binary. +.TP +.BR librecrypt_get_encoding (3) +Get encoding alphabet for the last algorithm in a +chain. + +.SH SEE ALSO +.BR crypt (3), +.BR crypt (5) |