The ciphers are different, but on the same principle: the characters in each are either single digits or combinations of two or three digits, standing some of them for letters, others for syllables or words, - the number of distinct characters which had to be deciphered being thus very considerable.
Both ciphers perhaps mean only "a very great number," and Fleischer (De glossas Habichtianis, p. 4) has shown that 1001 is certainly used in this sense.
To regard these letters as ciphers is a precarious hypothesis, for the simple reason that cryptography is not to be looked for in the very infancy of Arabic writing.
If they are actually ciphers, the multiplicity of possible explanations at once precludes the hope of a plausible interpretation.
In tables of logarithms of numbers to base io the mantissa only is in general tabulated, as the characteristic of the logarithm of a number can always be written down at sight, the rule being that, if the number is greater than unity, the characteristic is less by unity than the number of digits in the integral portion of it, and that if the number is less than unity the characteristic is negative, and is greater by unity than the number of ciphers between the decimal point and the first significant figure.